Tire pressure for all around XC riding? - Page 2- Mtbr.com
Page 2 of 3 FirstFirst 123 LastLast
Results 201 to 400 of 507
  1. #201
    mtbr member
    Reputation:
    Join Date
    Jan 2012
    Posts
    38
    I'm 150 pounds, and ride a hardtail. 35-40 psi is perfect, things roll faster, and pinch flats almost never happen. If your skills are up to the decrease in traction, than its wll worth the extra pressure for low rolling resistance, and running less risk of fixing a flat tire (nothing slows you down more) Even with a tubless set up, ride at least 30 or more to avoid the bead rolling and breaking the seal.
    "I am hard at work right now, you just can't tell because I'm wearing an apron!"

    BikeFAT.com

  2. #202
    mtbr member
    Reputation:
    Join Date
    Oct 2011
    Posts
    27
    For those running tubeless this is Stan's recommended starting point: divide your weight by 7, then subtract one for front pressure, add 2 for rear. For me at 200 lbs that works out to 28 front and 31 rear.

    Note that this the recommended starting point and not a firm rule. I am running 23 front and 26 rear on Maxxis Ikon 2.2.

  3. #203
    mtbr member
    Reputation:
    Join Date
    Jul 2009
    Posts
    253
    I just checked my pressure. Did a ride today with the dogs so it was pretty slow paced. Pressures are read from Specialized floor pump with gauge.
    16psi front- felt a little low, bottomed the tire once but no flat.
    20 psi rear.
    WTB Exiwolf 2.35 on Velocity Blunts

  4. #204
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by mobius911 View Post
    For those running tubeless this is Stan's recommended starting point: divide your weight by 7, then subtract one for front pressure, add 2 for rear. For me at 200 lbs that works out to 28 front and 31 rear.

    Note that this the recommended starting point and not a firm rule. I am running 23 front and 26 rear on Maxxis Ikon 2.2.
    That formula does not take into account tire width, which is a big factor. When I run the formula for me, I get very close pressures to what I use on 26"/2.4" tires. But on my XC bike that uses 1.9 tires, I use 10-15 PSI more.

  5. #205
    mtbr member
    Reputation:
    Join Date
    Mar 2010
    Posts
    21

    215 lbs male

    I run 35 in front with 2.3's and 40 in back with 2.1

  6. #206
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    25
    I usually run 20-25 PSI in my rear 2.0 tire. Tubeless 29er. Yesterday I bent the hell out of my Stan's Crest wheel going through an armored creek crossing at average speed. I was pretty shocked. At a 140 lb body weight I rarely have issues with wheels. I guess I'm going to start running 30 psi.

  7. #207
    mtbr member
    Reputation:
    Join Date
    Jan 2012
    Posts
    15
    190lbs with all my gear. 28 psi in the front, 32 psi in the rear on 2.24's

  8. #208
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    248
    175lbs and I run (pending trail and conditions) anywhere between 38 to 42. For the most part on faster trails the higher pressure and slower trail the lesser pressure.

    Mud I let a little out, sticky trails higher and dry usually I use the feel factor (if the tire is not sticking I let a touch out till it feels good)

    Can someone explain the "lower pressure the tire rolls faster" theory to me.......I dont get it :-/

  9. #209
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by spartacus View Post
    175lbs and I run (pending trail and conditions) anywhere between 38 to 42. For the most part on faster trails the higher pressure and slower trail the lesser pressure.

    Mud I let a little out, sticky trails higher and dry usually I use the feel factor (if the tire is not sticking I let a touch out till it feels good)

    Can someone explain the "lower pressure the tire rolls faster" theory to me.......I dont get it :-/
    Basically, on a rough surface higher pressures bounce more. the tire/wheel moves up more than forward.

    Lower pressure lets the tire conform to the terrain and maintain forward momentum.

    Same reason suspension is faster than rigid on rough terrain.
    mtbtires.com
    The trouble with common sense is it is no longer common

  10. #210
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    248
    Thank You. This makes sense
    I keep hearing this from some of the people out by me and it perplexed me because there was no explanation. I think they Just conveyed info they herd with out understanding why.

  11. #211
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by shiggy View Post
    Basically, on a rough surface higher pressures bounce more. the tire/wheel moves up more than forward.

    Lower pressure lets the tire conform to the terrain and maintain forward momentum.

    Same reason suspension is faster than rigid on rough terrain.
    No, that is not the theory. The theory is that a wider tyre is faster than a narrower tyre for MTB use because the longer, thinner contact patch requires the tyre to "lift" more than a fat narrow one. Schwalbe did a study looking at this and concluded as above. Some of the benefit is small (around 10watts IIRC) but some was surprisingly large. Depending upon the type of terrain. Note that on hard surfaces, (i.e. road bike) the opposite is true.

    WRT tyre pressure - as the decrease in pressure allows the above effect to occur, it will be faster, but at some point the extra drag of the bigger contact patch will have the opposite effect.

    Remember that simple physics means that the actual size of the tyre has no effect on the contact patch size - it is only the air pressure in the tyre. In other words a 26x1 tyre running 30psi will have the same contact patch size as a 29x2.3 tyre @30psi. The shape will change (long and thin vs short and fat), but the size won't. Generally speaking the long thin contact patch (narrower tyre) will have advantages in traction and braking, whilst the short and fat contact patch (wider tyre) will have advantages in cornering.

    This is why decreasing tyre pressure increases contact patch size which will improve traction due to the greater tyre surface area interaction with the terrain.

  12. #212
    Hoolie Ghoulie on Strava.
    Reputation:
    Join Date
    Sep 2010
    Posts
    3,080
    I am Mr 30 psi on both my Tubeless Ready Tire sets on both UST rimsets. Accidentally rode 25 psi tonight! I am now Mr 25 psi

  13. #213
    mtbr member
    Reputation: beerrun's Avatar
    Join Date
    Jul 2007
    Posts
    143
    I would add that pressures required depend on terrain. I did a 11 mile climb the other day on my steel rigid 8 speed, was great uphill with 40 rear 35 front. But then the washboard on the way down was crazy! I prob let out almost 20lbs on both wheels. Only way I could maintain control at speeds of 25-30mph. Had I had suspension with tubeless, I would have maintained the same pressures.

  14. #214
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by spartacus View Post
    Can someone explain the "lower pressure the tire rolls faster" theory to me.......I dont get it :-/

    Studies show you're faster when you can stay connected to the trail. Larger contact patch=more traction=faster
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  15. #215
    New MTB XC Racer
    Reputation: Rum Runner's Avatar
    Join Date
    Feb 2008
    Posts
    253
    Quote Originally Posted by ZXFT View Post
    Studies show you're faster when you can stay connected to the trail. Larger contact patch=more traction=faster
    Also I would imagine some tire deflection over smaller bumps uses less energy than a harder tire transmitting that energy through the frame, suspension and even rider...
    just my two cents.....

    Plus more traction as stated above...

    My two cents .....

    Cheers,
    Paul

  16. #216
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by Rum Runner View Post
    Also I would imagine some tire deflection over smaller bumps uses less energy than a harder tire transmitting that energy through the frame, suspension and even rider...
    just my two cents.....

    Plus more traction as stated above...

    My two cents .....

    Cheers,
    Paul
    Makes sense. When suspension moves most of the energy is lost in damping.

  17. #217
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Its kinda like the 29er argument: If it rolls smoother, it will be faster.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  18. #218
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    13
    36 psi.. sounds pretty reasonable to me...

  19. #219
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by snowgage View Post
    36 psi.. sounds pretty reasonable to me...
    Reasonable to who? Riding what?
    It depends on tire width, terrain, rider weight, rim width, tube/tubeless among other things. Just for myself I run 22-40 PSI in different bikes (used on the same trails).

  20. #220
    mtbr member
    Reputation:
    Join Date
    Dec 2011
    Posts
    317
    I weigh about 83kg and have been running 25 front/ 28 rear, Racing Ralph 2.25 tyres on loose/ rocky conditions. Managed to put a dent in my carbon Roval front rim on the weekend from hitting a rock so i'll be adding a few psi of pressure from now on. Bit less grip but better than destroying carbon rims.

  21. #221
    mtbr member
    Reputation:
    Join Date
    Feb 2012
    Posts
    14
    Great post with lots of input. I read all the posts and did as some suggested and took my bike and floor pump with gauge down to my little single track loop with one steep and rocky descent with a narrow bridge at the end. I started with pressure in the upper 30psi range in both tires and played around. I ended up with 25 for the front and 28 for the back and the increased handling was great and very noticeable in overall control and less "bouncing" when compared to the higher tire pressures.

  22. #222
    derp
    Reputation: danielsilva's Avatar
    Join Date
    Aug 2011
    Posts
    948
    Prefer 25 psi on the front, 30 psi on the back.

  23. #223
    mtbr member
    Reputation: FLMike's Avatar
    Join Date
    Sep 2008
    Posts
    974
    im 170 lbs

    On a previous bike with 2.4 Maxxis advantages, I preferred 28 psi front, 30 rear

    I recently bought a Cannondale RZ 120 and went with 2.1 Kenda Nevegals. I prefer to be at 35 psi otherwise it feels way too squirmy in the corners. Although I find starting at 40 psi its noticeable too hard over roots.

    all tubed tires

  24. #224
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    18
    3,5bar in Specialized Storm Control 26x2.0

  25. #225
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    18
    3 bar in racing ralph 26x2,25

    But i might be way off.

  26. #226
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,794
    Quote Originally Posted by Bech View Post
    3 bar in racing ralph 26x2,25

    But i might be way off.
    Does 1 bar = 15psi?

  27. #227
    mtbr member
    Reputation: FLMike's Avatar
    Join Date
    Sep 2008
    Posts
    974
    Quote Originally Posted by fsrxc View Post
    Does 1 bar = 15psi?
    1 bar = 14.5037738 pounds per square inch (no, i didnt know that off the top of my head. I used google)

  28. #228
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    14.5psi equals 1 bar

  29. #229
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Some high pressures being run. I usually shoot for 28psi but I'll run 25psi if that's what it's leaked down too.

  30. #230
    mtbr member
    Reputation: chantheman84's Avatar
    Join Date
    Sep 2011
    Posts
    175
    It really depends on the tires, trail conditions, and riding style, I can run from 18 to 30 front and 20 to 40 rear

  31. #231
    mtbr member
    Reputation:
    Join Date
    Sep 2009
    Posts
    10
    run 50 psi

  32. #232
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    4,971
    I'm 59 yrs old, 165 lbs, medium fast on the descents in Park City Utah. Primarily interested in climbing speed. I had been running 28 PSI in front (on a Yeti 575 with a 150 mm front fork) on a WeirWolf LT 2.55 and 30 PSI on a 2.30 Tioga Psycho Genius on the back (on Stan's Crest rims, tubeless). More than a 2 PSI decrease causes the tires to begin to fold under while cornering. I have now placed Conti X-King, 2.4 RS front and back, tubeless, and find I still need to run 30 rear and 28 front to get the same resistance to the fold under while cornering. I'd run lower pressure were it not for the cornering issue because it makes climbing a dream.

  33. #233
    mtbr member
    Reputation:
    Join Date
    Jan 2012
    Posts
    3

    Cool-blue Rhythm

    155lbs - I am running ADventage tubeless and I ran 40psi back and front this week.
    I encountered some front wheel control issues on soft over hard, OK my lack of skills is probably the number one factor but my tire pressure may have been too high. I never had the same feelings when running 20-30 psi.

  34. #234
    mtbr member
    Reputation: dirtdan's Avatar
    Join Date
    Jun 2011
    Posts
    1,619
    I'm not racing (yet), but been riding since the 90's. I started out running tubes and 50 psi back then and now I run tubeless and in the range of 23-26. I'm 160 pounds and have ridden Continentals pretty much all of the time with my preference now with Trail Kings with a 2.2 in the back and a 2.4 in the front. I've been experimenting with the tubeless version vs. the non-tubeless version and it seems even in the rocky and rooty areas that I ride that the lighter, non tubeless versions holds up just fine.

    After running tubes and high pressures and then no tubes and low pressure, I confidently feel there is no comparison between the two in terms of speed and confidence. I've also discovered that I can convert just about any rim to run tubeless with just stan's tape and a valve. One rim I had was stubborn and I had to add a layer of gorilla tape over the rim tape to get it to seal, but I think just about any crappy rim can be converted with the help of an air compressor.

  35. #235
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,794
    Quote Originally Posted by vttix View Post
    155lbs - I am running ADventage tubeless and I ran 40psi back and front this week.
    I encountered some front wheel control issues on soft over hard, OK my lack of skills is probably the number one factor but my tire pressure may have been too high. I never had the same feelings when running 20-30 psi.
    Yes, 40psi in the front tire could be reducing traction and control.

  36. #236
    mtbr member
    Reputation:
    Join Date
    Feb 2012
    Posts
    19
    25ish. I weigh 140.

  37. #237
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    2,548
    Around 35 with 190 pounds on the bike. Much less and the tires squirm and squeal over obstacles.

  38. #238
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    302
    I'm running 20psi front and 24psi rear with Specialized LK Control 2bliss tires in 2.0 width with Stans rim strips and a home brew sealant. I'm 160 pounds with an average riding style, no huge jumps or anything like that. I mainly ride on loose gravel/decomposed granite over concrete like hardpack.

  39. #239
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    4,971
    Apparently, it also depends greatly on your pressure gauge. I finally got a good quality gauge. It's about 5 PSI lower than my floor pump and 4 PSI...in the other direction...from another tire gauge I have.

  40. #240
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    43
    why are you guys running such high pressures? What kind of terrain are you running?

    I run 20ish up front and 25ish in the back. I ride sandy hard pack with roots and lots of pine straw and leaves. If I raise the pressure to 25 in the front it slides all over the place, the front washes out like crazy. If I leave it at 18 to 20 it rides great. I hit roots and large curb sized roots with no problem at all. I could not imagine running 30 or 40.

    I have a 2.2 ikon exo up front (or 2.4 ardent) depending on the weather and a crossmark 2.1 out back.
    2012 Trek Superfly 100 AL
    2016 Canfield Yelli Screamy

  41. #241
    Austin, Texas
    Reputation: smokehouse4444's Avatar
    Join Date
    Apr 2011
    Posts
    174
    The tires that are "high pressure" tires, such as the Maxxis Ikon, what are you guys running in them. I'm about 230# and riding in hardpack/rocky/loose over hp, with 29 x 2.2 Ikons. Should I just run them at the normal (for me) 35ish psi? Or should they be run with higher pressure. What is the advantage of having a high pressure tire?

  42. #242
    mtbr member
    Reputation: chantheman84's Avatar
    Join Date
    Sep 2011
    Posts
    175
    Quote Originally Posted by smokehouse4444 View Post
    The tires that are "high pressure" tires, such as the Maxxis Ikon, what are you guys running in them. I'm about 230# and riding in hardpack/rocky/loose over hp, with 29 x 2.2 Ikons. Should I just run them at the normal (for me) 35ish psi? Or should they be run with higher pressure. What is the advantage of having a high pressure tire?
    I would definitly do some testing, start at 35psi and work your way down to where you'll get the most amount of grip without dinging the rims and or rolling the tires under, during hard cornering. I own Ikons also and weigh 150lbs with a 25lbs bike full riding gear is 175lbs total, I run 25-28 psi in mine front, and alittle more in the rear like 30-35 to help decrease rolling resistance , ran tubeless. On the road rides on my mountain bike I jack em up to 40psi

  43. #243
    mtbr member
    Reputation:
    Join Date
    Sep 2011
    Posts
    11
    I'm 185lbs, running 35psi F 38psi R on Maxxis crossmark 2.0 with Dt Swiss X1600 rims for a few weeks since converting to tubeless, so far so good......climb better and no more flats........will try to lower a couple psi this weekend....see how it handles.....

  44. #244
    Heavylegs
    Reputation:
    Join Date
    Apr 2012
    Posts
    168

    We the people ...

    Are you all racing or something. I use too race and neve:crazy paid that close attention to PSI ever. All I have ever done was put in about 40 in remembering how hard or easy it was to sqeeze and go ride. Not that you can't notice a difference in a 3-4 psi change, but you would have to be tuned into your bike pretty well to notice it. Besides that if I were to run anything less than 30 psi I would get snakebit every time out.

  45. #245
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by redd4573 View Post
    Not that you can't notice a difference in a 3-4 psi change, but you would have to be tuned into your bike pretty well to notice it.
    IMO +/- 3-4 psi is a huge difference that doesnt require a 6th sense to detect.

    Quote Originally Posted by redd4573 View Post
    Besides that if I were to run anything less than 30 psi I would get snakebit every time out.
    Tubeless man... Its the way of the future.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  46. #246
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    8
    Recommendations on pressure. Just got a '12 Dawes Haymaker 1200 17" with this setup

    Rims WTB Speed Disc Double Wall Aluminum
    Tires WTB Velociraptor Blackwall 26 x 2.10

    Sidewall says 40-60 so I put them at 50. I am 135# and a total noob. I ride mostly well packed gravel trail with a few pretty clear dirt trails with minimal roots and rocks. 50 felt good, but my hands were numb after a 15 minute ride on these dirt trails. I know there could a lot of other factors to that but hoping for a bit more cush if I lower the tire pressure.

  47. #247
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    At 135lbs I'd say you should be in the mid 20's psi wise. 50 is just crazy

  48. #248
    mtbr member
    Reputation: jacksonj51's Avatar
    Join Date
    Mar 2012
    Posts
    73
    180lbs... run 24psi front & 27psi rear in just about all my tubeless set ups no matter the tire (mostly schwalbe's)

  49. #249
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    12
    Tubeless. 33 psi rear and only 16 psi front in a 2.25" tire - I have a rigid fork so it's my only suspension. Never burped... yet

  50. #250
    Heavylegs
    Reputation:
    Join Date
    Apr 2012
    Posts
    168
    Great at this rate we will be talking nito and beadlocks soon Now lets use our heads a little better than we have been . Tire makers have invested alot of $$$ in R&D, I personally run Panaracer Dart and Smoke Tube combo .I find they work for me. I run roughly 35-40 psi, I say roughly because I really only get as close as I need to be because most tire guages are very inaccurate anyways get any three different ones and try it. That being said the side walls on my tires read recomended psi between 30-50 psi. Now I'm not cracking on anyone's veiw on this topic but I believe the tire makers are spot on. I have had little issues with traction outside of poor judgement in placement of said tires. If you look at a correctly inflated tire from the approching angle it revels a crown, if one were to lay the wheel and tire at say 15 - 20 degrees to the left or right the contact area remains the same. And with weight on the bike say all of my 200lbs I could find the tires rolling a bit and increasing this area.Me myself and I believe that none of us would go out and deflate our motorcycle or car tires 10 -15 percent to GAIN traction??? I understand that this is not a great comparison but it's not to far off point. But the most important thing is we all have fun riding even if it seems goofy how others do things

  51. #251
    Mulleticious
    Reputation: BigwheelsRbest's Avatar
    Join Date
    Jun 2007
    Posts
    1,494
    ah yes but if you were running tubeless with UST tires the bead sits tighter, then throw in no suspension and a nice fat tire and all you need is low pressure for less stress on the wrists.
    OK so I wouldnt do it in my car but then I dont go 100 mph on my bike...

  52. #252
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by redd4573 View Post
    Great at this rate we will be talking nito and beadlocks soon Now lets use our heads a little better than we have been . Tire makers have invested alot of $$$ in R&D, I personally run Panaracer Dart and Smoke Tube combo .I find they work for me. I run roughly 35-40 psi, I say roughly because I really only get as close as I need to be because most tire guages are very inaccurate anyways get any three different ones and try it. That being said the side walls on my tires read recomended psi between 30-50 psi. Now I'm not cracking on anyone's veiw on this topic but I believe the tire makers are spot on. I have had little issues with traction outside of poor judgement in placement of said tires. If you look at a correctly inflated tire from the approching angle it revels a crown, if one were to lay the wheel and tire at say 15 - 20 degrees to the left or right the contact area remains the same. And with weight on the bike say all of my 200lbs I could find the tires rolling a bit and increasing this area.Me myself and I believe that none of us would go out and deflate our motorcycle or car tires 10 -15 percent to GAIN traction??? I understand that this is not a great comparison but it's not to far off point. But the most important thing is we all have fun riding even if it seems goofy how others do things
    You're also running tires developed like 20+ years ago and they're standard clinchers. Try running tubeless and you'll change your views. PS my tires have a MAX of 40 psi

  53. #253
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    28
    My front tire is around 2,2bar, rear is 2,5bar. Good traction, I don't like high pressures at all.
    Ride to live, live to ride!!!

  54. #254
    Heavylegs
    Reputation:
    Join Date
    Apr 2012
    Posts
    168
    I have no need to ride tubless . Seems to be several mounting issues with some products and others make no sense to me at all. Most people running tubless still carry a spare tube with them? They only developed tubless for the DH racing crowd which is understandable when running fast and balls out over things 90% of riders will never attempt. But the folks in marketing got an idea push it though the media and when the mags get an itch for advertisng $$$'s they say they like the Kool Aid because it reduces wieght on thier 29ers and the mad dash for the NEXT cool thing had started.Oh well I'll just keep mounting my trusted 20 yr old tires and tubes ( which takes about 10 mins to do) and injoy my way of riding while others are spending their hard earned $$$'s on this unneeded technology that the Kool Aid machine keeps serving up

  55. #255
    mtbr member
    Reputation: jacksonj51's Avatar
    Join Date
    Mar 2012
    Posts
    73
    No mounting issues, don't carry a spare, low tire pressure, takes 10 min to mount tubeless, no flats in over 2 years since going tubeless, and forgot what a tube even looks like. Loving the tubeless kool-aid.

  56. #256
    mtbr member
    Reputation: FLMike's Avatar
    Join Date
    Sep 2008
    Posts
    974

    No good

    Quote Originally Posted by redd4573 View Post
    I have no need to ride tubless . Seems to be several mounting issues with some products and others make no sense to me at all. Most people running tubless still carry a spare tube with them? They only developed tubless for the DH racing crowd which is understandable when running fast and balls out over things 90% of riders will never attempt. But the folks in marketing got an idea push it though the media and when the mags get an itch for advertisng $$$'s they say they like the Kool Aid because it reduces wieght on thier 29ers and the mad dash for the NEXT cool thing had started.Oh well I'll just keep mounting my trusted 20 yr old tires and tubes ( which takes about 10 mins to do) and injoy my way of riding while others are spending their hard earned $$$'s on this unneeded technology that the Kool Aid machine keeps serving up
    While I dont ride tubeless, im educated enough on the subject to realize youre completely out of touch with reality. Engaging in attempts to correct you, as another has already realized, is fruitless.

    With a recent registration date and 13 posts, id suggest lurking and reading more and posting a tad less.

  57. #257
    mtbr member
    Reputation: jacksonj51's Avatar
    Join Date
    Mar 2012
    Posts
    73
    Gonna go lurk and read how to install tubes and up my tire pressure in order to make my riding more enjoyable, thanks for the recommendation!

    #FeelingsHurt

  58. #258
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by jacksonj51 View Post
    No mounting issues, don't carry a spare, low tire pressure, takes 10 min to mount tubeless, no flats in over 2 years since going tubeless, and forgot what a tube even looks like. Loving the tubeless kool-aid.
    LOL this exactly. I run tubeless compatible rims and tires and it's super easy to use and has been dead nuts reliable.

  59. #259
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    2,673
    redd,
    I fully understand not wanting to get caught up on all the equipment hype, but as someone that spent many years exclusively with the Dart/Smoke combo (I ran them for over a decade) I strongly encourage you to try some new tires. There are much better tires available today.
    Warning: may contain sarcasm and/or crap made up in an attempt to feel important.

  60. #260
    Heavylegs
    Reputation:
    Join Date
    Apr 2012
    Posts
    168
    Wow you guys are easy. I've been riding for close to 20 yrs I have seen things come and go some great some not so much. I have tried many diferent types of tires and I do run a couple semi slicks later in the summer if trails stay dry more and soft spots firm up. Like I have stated before this is just my opion I supose we are all allowed to have one. For me mtbing is a way to relax and injoy life. See inside these last 20 yrs I've raced and trained my way into as I called it cycling slavery. Not to say that all that doesn't or can't make others happy but it's not for me and after slowing down I saw this sport as I did when I first started riding, SIMPLE. Just passing some zen like info on to others open to those who like a sound debate. If I upset anyone..... well sorry I was to busy riding and not lurking on a forum learning proper etiquette Hope to meet you all on the trail someday. Oh and I will not be hard to find I will be the slow guy you are passing with the retro tires on a hardtail with a smile on his face.

  61. #261
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203

    Smile

    Quote Originally Posted by redd4573 View Post
    I have no need to ride tubless . Seems to be several mounting issues with some products and others make no sense to me at all. Most people running tubless still carry a spare tube with them? They only developed tubless for the DH racing crowd which is understandable when running fast and balls out over things 90% of riders will never attempt. But the folks in marketing got an idea push it though the media and when the mags get an itch for advertisng $$$'s they say they like the Kool Aid because it reduces wieght on thier 29ers and the mad dash for the NEXT cool thing had started.Oh well I'll just keep mounting my trusted 20 yr old tires and tubes ( which takes about 10 mins to do) and injoy my way of riding while others are spending their hard earned $$$'s on this unneeded technology that the Kool Aid machine keeps serving up
    Tubeless is about physics. You run lower pressures. Benefits in traction and braking (=speed). And way less flats. I have had 1 flat in the last 4 years of running tubeless.

    And I checked, the earth is not flat.

  62. #262
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by redd4573 View Post
    Wow you guys are easy. I've been riding for close to 20 yrs I have seen things come and go some great some not so much.
    I know, tubeless is a fad, just like disc brakes and suspension forks.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  63. #263
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    12
    Quote Originally Posted by redd4573 View Post
    I have no need to ride tubless . Seems to be several mounting issues with some products and others make no sense to me at all. Most people running tubless still carry a spare tube with them? They only developed tubless for the DH racing crowd which is understandable when running fast and balls out over things 90% of riders will never attempt. But the folks in marketing got an idea push it though the media and when the mags get an itch for advertisng $$$'s they say they like the Kool Aid because it reduces wieght on thier 29ers and the mad dash for the NEXT cool thing had started.Oh well I'll just keep mounting my trusted 20 yr old tires and tubes ( which takes about 10 mins to do) and injoy my way of riding while others are spending their hard earned $$$'s on this unneeded technology that the Kool Aid machine keeps serving up
    If you live where we do you need to run tubeless otherwise you'd go crazy - at least one puncture every ride. It's the hoarthorn and blackthorn and bloody whoknowswhatthorn but they get in your tubes mate...

    And in any case ghetto tubeless doesn't generate much profit for anyone, and loses the tube makers some.

  64. #264
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    572
    I donít have a gauge, so I donít really know what I run my tires at (and gauges are notoriously inconsistent anyway Ė well, consistent with themselves but not from one gauge to another). I just do it by feel. Generally I use the squirrely cornering rule. If I am feeling that, I inflate what I guess is probably 2-3 psi and see how it feels. Iím running new tires now (2.4 in front and 2.35 in back, up from 2.1s) so Iím still playing with getting the right feel. But generally, I like it as low as it can go before I start to feel that cornering squiggle. Iím riding all rigid (and loving it!) so I value the extra give. Itís a better feeling, too, to be running lower. Like I am more inside the terrain than just on top.

  65. #265
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by wahday View Post
    I donít have a gauge, so I donít really know what I run my tires at (and gauges are notoriously inconsistent anyway Ė well, consistent with themselves but not from one gauge to another). I just do it by feel. Generally I use the squirrely cornering rule. If I am feeling that, I inflate what I guess is probably 2-3 psi and see how it feels. Iím running new tires now (2.4 in front and 2.35 in back, up from 2.1s) so Iím still playing with getting the right feel. But generally, I like it as low as it can go before I start to feel that cornering squiggle. Iím riding all rigid (and loving it!) so I value the extra give. Itís a better feeling, too, to be running lower. Like I am more inside the terrain than just on top.
    Because if there's anything more accurate than a numerical gauge it's the human touch.......

  66. #266
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    27
    I run my Nobby Nic's 2.1 on 2.3bar with latex tubes. They are very soft compared to Smart Sam and Albert.

  67. #267
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    572
    Quote Originally Posted by Ilikebmx999 View Post
    Because if there's anything more accurate than a numerical gauge it's the human touch.......
    Touche!

    My point was simply that just because Jimmy's gauge reads 25psi, it won't necessarily be the same as 25psi on your gauge. So don't take other peoples' numbers too seriously - make your own adjustments for what feels best. Use your own gauge if you want (and always use the same one), but as far as seeking a "standard" pressure, that's going to be hard to nail down with so much variability (in gauges, tires, riders, etc.)

    The truth is I'm too lazy and cheap to go get a gauge, so I ride and make adjustments for what feels best. And while the ladies say I have a magical touch, you're right, I'm not a human pressure gauge...

  68. #268
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    12
    Got wrapped up in all the hype and bought a decent (expensive) digital pressure guage. Can't believe what I'm reading on it (and riding on)!

    Also riding rigid, so I value a soft fat tire up front, but I measured the pressure last night (after reading these posts) and it was 13 psi

    Can that be right? It feels soft, but I don't get the squiggly corners yet. It feels just right - a bit of suspension and really good grip. It is a Nobby Nic 2.25" snakeskin running tubeless...

    (Rear is different - that's at 33 psi which feels like it's right)

  69. #269
    New MTB XC Racer
    Reputation: Rum Runner's Avatar
    Join Date
    Feb 2008
    Posts
    253
    I got a new tubeless wheel set in the fall and have now had some rides and a race on them and I can say I am definitely having a positive experience running UST tubeless rims and tires.
    Running Mountain King 2.2's and really liking them.
    I had to add just the smallest amount of Stans to seal around the valve stem and totally seal off the bead. Probably 1/2 oz in each tire. They held air all winter hanging in the garage and so far seem to be holding air well.
    I started out around 25 psi and each ride dropped a little and this past weekend and the first race 2 days ago I ran approx 18-19 psi F/R (GT i-drive FS, 145lbs rider)
    I have been able to clear tough sections better than most so this means I have pretty good traction due to the variety of tires the other guys are riding on. I won't go lower than this and maybe up a pound or 2 for race days as our course is rough rocky and rooty.
    At the local races last year I only finished 3-7 races due to multiple flats. This first race I didn't hold back, other than building up some confidence, over the 3 laps and no flats ! I did look down a few times though.

    Cheers,
    Paul

  70. #270
    mtbr member
    Reputation:
    Join Date
    Jun 2011
    Posts
    203
    Quote Originally Posted by redd4573 View Post
    Me myself and I believe that none of us would go out and deflate our motorcycle or car tires 10 -15 percent to GAIN traction??? I understand that this is not a great comparison
    Actually you are not far off, and YES, I WILL GO AND DEFLATE MY VEHICLE TIRES TO GAIN TRACTION!!! Every time I take my Jeep off road or when I need the extra traction here in the great NorthEast in the snowy season, I will deflate my tires just to gain that extra traction.

    That said, I fully understand the low psi and the benifits of it. I myself do not run lower psi on my MTB because I have not had the need to YET. When I find myself riding trails more regularly that require me to do so, I will.

    As far as to say whats better, tubes or tubeless, it depends on what you need for where you ride.

    So how low is too low? Well thats up to you to decide for yourself. I could ask a few questions on the subject, but seeing as this whole thing is a hotly debated subject to begin with, I will leave my questions out for now. A lot of what I wanted to ask about has already be said, so I will leave it at that.

    As to the arguement about "riding for 20 years," does not make you an expert. I have been riding since I was 5yrs old, that means I have been riding for the last 28 years, am I am expert, absolutly not. Will I pretend to be something I am not, heck no. Anyone who has lived and paid the slightest bit of attention has seen fads come and go.

    That all said, did I say you lied, NO, did I hurt someones feelings by what I said, ehh maybe, it happens, its life.

    Bottom line: It doesnt really matter unless you are happy and enjoying your setup on your bike. There are a ton of variables that go into YOUR setup of YOUR bike. Yes it is good to seek opinion in order to educate ones self, but it is bad when you belittle the opinion becasue it is not like your own.

  71. #271
    Heavylegs
    Reputation:
    Join Date
    Apr 2012
    Posts
    168
    Did the voices come back I never claimed to be a expert. Just trying to have a good discusion and a gain and understand of others opinons. How does stating MY opinon belittle others? But then agin I'm not an expert on THOSE sort of things

  72. #272
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    13
    I rode at the weekend with 40 psi in my Continental Rubber Queens (2.2). The downhill was terrible, I'll be looking to come down to around 30 psi.

  73. #273
    mtbr member
    Reputation:
    Join Date
    Jun 2011
    Posts
    203
    Quote Originally Posted by redd4573 View Post
    Did the voices come back I never claimed to be a expert. Just trying to have a good discusion and a gain and understand of others opinons. How does stating MY opinon belittle others? But then agin I'm not an expert on THOSE sort of things
    I say it like I see it, I did not say that YOUR particular post/opinion quoted was in question, but after reading a few pages of replies and seeing posts that were negative in nature because one persons opinion differed from theirs, I felt the need to say it.

    I have seen it before where people think that because they have been doing something for XX years that they are gods gift to (fill in the blank). It is typically these people that are almost always wrong and give bad advice. Your post was the last one read by myself, so it was the one used as an example. If I was calling you out directly, I would have typed your screen name in directly. The only thing I said that was in your direction redd4573 was the very first paragraph about airing down just to gain traction.

    Everything else I had to say was a general statement put out there and not directed towards anyone in particular. nothing more, nothing less.

  74. #274
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    I don't think anyone can seriously debate the benefits on traction of deflating a tyre. After all the size of the tyre (width, height, diameter) is irrelevant in determining the size of the contact patch - the only relevant factors are the total weight and the PSI in the tyres. Simple physics. Put another way, a 26er running a 1" wide tyre will have the same contact patch size as a equivalent weight 29er running a 3" wide tyre, provided that they are running the same PSI. Different shape, but same total size.

    SO I can double my contact patch size by running 20psi when I used to run 40psi. Benefits are in better traction, braking and cornering. That is until the negative effects of tyre movement rob the bike of the control necessary to handle comfortably. Or I puncture too often. Or both.

    So, it is better to adopt the approach of achieving the minimum pressure to produce the results you are looking for, than the other way around.

  75. #275
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by skiwi View Post
    I don't think anyone can seriously debate the benefits on traction of deflating a tyre. After all the size of the tyre (width, height, diameter) is irrelevant in determining the size of the contact patch - the only relevant factors are the total weight and the PSI in the tyres. Simple physics. Put another way, a 26er running a 1" wide tyre will have the same contact patch size as a equivalent weight 29er running a 3" wide tyre, provided that they are running the same PSI. Different shape, but same total size.

    SO I can double my contact patch size by running 20psi when I used to run 40psi. Benefits are in better traction, braking and cornering. That is until the negative effects of tyre movement rob the bike of the control necessary to handle comfortably. Or I puncture too often. Or both.

    So, it is better to adopt the approach of achieving the minimum pressure to produce the results you are looking for, than the other way around.
    ..........uhhhh

  76. #276
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    6
    I use TLAR* ie my thumb.


    *that looks about right.


    I usually adjust the tire pressure to the conditions of the trail.

  77. #277
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by Ilikebmx999 View Post
    ..........uhhhh
    Like I said - simple physics. And most people into cars & bikes don't get it. Like you I take it....

  78. #278
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by skiwi View Post
    Like I said - simple physics. And most people into cars & bikes don't get it. Like you I take it....
    So let's say a 200 lb rider sitting on a bike with a 1" wide tire at 20psi and a 200 lb rider sitting on a bike with a 3" wide tire at 20 psi will have the exact same contact patch?

  79. #279
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by Ilikebmx999 View Post
    So let's say a 200 lb rider sitting on a bike with a 1" wide tire at 20psi and a 200 lb rider sitting on a bike with a 3" wide tire at 20 psi will have the exact same contact patch?
    No, they will have the exact same size contact patch. The shape will be different.

  80. #280
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    Quote Originally Posted by skiwi View Post
    No, they will have the exact same size contact patch. The shape will be different.
    How is contact patch and size of contact patch not the same thing?

    The amount of tire touching the ground will be exactly the same is what you're saying then?

  81. #281
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by Ilikebmx999 View Post
    How is contact patch and size of contact patch not the same thing?

    The amount of tire touching the ground will be exactly the same is what you're saying then?
    Contact patch size and shape are different things.

    PSI is pounds per sq inch.That is the only thing holding up the weight of the bike/rider (less some sidewall stiffness).

    So, in your example, 200lbs/20psi = 10sq inches. That is your total contact patch size (5 sq inches per tyre). For both the 3" wide tyre and the 1" wide tyre.

    Contact patch size stays the same, but shape doesn't. As your tyre goes wider (at the same pressure), the contact patch shortens and widens. Hence you are trading off traction & braking for cornering.

  82. #282
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    You brought up shape not me. I'm specifically talking about the amount of tire touching the ground.

  83. #283
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    It will be the same. Same total area. Different shape.

  84. #284
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,430
    I ride exclusively in dirt. I'm going to go ahead and say your theory doesn't apply.

  85. #285
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by Ilikebmx999 View Post
    I ride exclusively in dirt. I'm going to go ahead and say your theory doesn't apply.
    BTW, this is no "theory". It is simple fact. It applies to Tarmac and Dirt equally (albeit with different trade offs). If you don't believe it works this way, wander down to your local 4wd club and try and convince them about your understanding of the physics ;-)

    Good luck with that.

  86. #286
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by Ilikebmx999 View Post
    I ride exclusively in dirt. I'm going to go ahead and say your theory doesn't apply.
    Its not "his theory", its basic physics. The contact area will be more or less the same, maybe the wider tire will have a few more knobs on the side touching the ground at lower pressure, making the patch a tad larger, but not significantly larger.
    If we take a completely smooth tire with a thin carcass (like a road bike) then the area will be almost identical for the same pressure.

  87. #287
    mtbr member
    Reputation:
    Join Date
    Jun 2011
    Posts
    203
    so what your are telling me is that my contact patch will be the same as everyone elses at 20 psi even though I am 300lbs and someone else is 150lbs? I understand that it might not be a significant change in the size or shape of the patch, but I would have to disagree that the contact patch will be exactly the same regardless of bike and rider weight with different size/width tires.

    If you have a 1 inch wide tire and a 3 inch wide tire both at 20 psi, the 3 inch wide tire is gonna have a larger contact patch on the same bike with the same rider.

    I know it is considered apples and oranges here, but I have to make the comparison. This would be like you saying that the contact patch of a vehicle tire but on the same truck is exactly the same regardless of its width. A 12.5 inch wide vehicle tire has a larger patch over the same tire in a skinnier width.

  88. #288
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    32
    At the risk of being flamed, i didn't read the whole thread... no that's not what he is saying. For a 300lb load at the same psi your total contact patch area is the same whether it is a 1" or 3" wide tire.

    300lb/20 psi = 15 Sq. In

    Now, if you only have a 150lb rider at the same pressure, your contact area is reduced...
    150lb/20psi = 7.5 sq. in.

    Having said that, in all honesty, you may not be running the same pressure to generate the same 'feeling' for the rider (after all tire 'squish does act as the 1st bit of suspension)... but that's what they were trying to state.
    Last edited by joqpub4; 06-01-2012 at 12:29 PM.
    '01 GT Aggressor 2.0
    '97 Jamis Dakota (CrMo)
    C-dale Pro Comp - Road

    Why am I on the computer and not riding???

  89. #289
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by bandit1 View Post
    so what your are telling me is that my contact patch will be the same as everyone elses at 20 psi even though I am 300lbs and someone else is 150lbs? I understand that it might not be a significant change in the size or shape of the patch, but I would have to disagree that the contact patch will be exactly the same regardless of bike and rider weight with different size/width tires.

    If you have a 1 inch wide tire and a 3 inch wide tire both at 20 psi, the 3 inch wide tire is gonna have a larger contact patch on the same bike with the same rider.

    I know it is considered apples and oranges here, but I have to make the comparison. This would be like you saying that the contact patch of a vehicle tire but on the same truck is exactly the same regardless of its width. A 12.5 inch wide vehicle tire has a larger patch over the same tire in a skinnier width.
    No, If you are 300ilbs and another person is 150lbs then the different weights would mean different contact patch sizes, if you are running the same PSI. If you have 2 people the same weight, and running the same PSI, then the contact patch size wold be the same - regardless of the size of the tyre.

  90. #290
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by joqpub4 View Post
    At the risk of being flamed, i didn't read the whole thread... no that's not what he is saying. For a 300lb load at the same psi your total contact patch area is the same whether it is a 1" or 3" wide tire.

    300lb/20 psi = 15 Sq. In

    Now, if you only have a 150lb rider at the same pressure, your contact area is reduced...
    150lb/20psi = 7.5 sq. in.

    Having said that, in all honesty, you may not be running the same pressure to generate the same 'feeling' for the rider (after all tire 'squish does act as the 1st bit of suspension)... but that's what they were trying to state.
    Exactly. It's an important concept to get across in the debate about how to get the best performance out of your bike.

  91. #291
    mtbr member
    Reputation:
    Join Date
    Jun 2011
    Posts
    203
    After reading an article on the subject, I think I understand the whole concept better... I will share an excert of the article I just read about this subject.

    Tire Width. There is a view that a 20 mm width tire is faster than a 23 by virtue of its smaller cross section and lighter weight. Interestingly enough, this is not true. The people making the Torelli tires had noticed that the pro teams that they sponsored asked for 23s because they felt they were faster. When they investigated and did the testing, they found that the riders were correct. Let me explain.

    Let's assume a 200 pound rider and bike unit. Let's also assume that the weight is distributed half over each wheel. That means that each wheel is supporting 100 pounds. Now, with a pressure of 100 pounds per square inch, the contact patch is one square inch. This is true no matter how fat the tire.

    What changes when the tire gets fatter is the shape of the contact patch. With a 20, the contact patch is a long oval. With the fatter tire, the contact patch gets shorter and wider.

    When a rider is using a skinnier tire, the long contact patch means he is flexing a wider arc of the tire casing, flexing more of the tire, causing more wasted energy from the internal friction of the tire and tube. The rider with the fatter tire is flexing fewer cords at a time.

    There is clearly an optimum size, and the fact that racing tubulars are around 22 should keep us from getting super wide tires looking for yet more speed. Other losses probably kick in as the tire gets still fatter. For me, the bike feels like it doesn't have any snap or jump when we stray from the optimum which I believe to be in that 22-23 mm range.

    Some have suggested that the skinnier tires make up for their losses because of their lower aerodynamic drag. This could be true for the solo time-trialist, I'm not sure. For the pack rider, it clearly is not an important consideration.
    Here for the full article

    There is also this one but it refers to motor vehicle tires.

  92. #292
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by bandit1 View Post
    After reading an article on the subject, I think I understand the whole concept better... I will share an excert of the article I just read about this subject.
    Good summary and entirely correct. Interestingly, there is similar evidence (albeit from Schwalbe) of the same effect in MTB i.e. wider is faster.

  93. #293
    mtbr member
    Reputation:
    Join Date
    Jun 2011
    Posts
    203
    yea there are some articles that get into it deep talking about what happens at the leading edge of the contact patch with rolling resistance and the rubber fibers bending and what not. Made my head hurt reading it.

  94. #294
    old fart
    Reputation:
    Join Date
    Mar 2010
    Posts
    1,203
    Quote Originally Posted by bandit1 View Post
    yea there are some articles that get into it deep talking about what happens at the leading edge of the contact patch with rolling resistance and the rubber fibers bending and what not. Made my head hurt reading it.
    I used to care about it as I tried to get my 26er race bike faster. Definitely proved it to my own satisfaction. However since migrating to a 29er, the dynamics are entirely different, and I've forgotten all about it. The 29er is plenty fast without obsessing about contact patch shapes...

  95. #295
    mtbr member
    Reputation:
    Join Date
    Jun 2012
    Posts
    13
    Tire pressure varies for each tire. Tubed or tubeless? Front or back? You can go lower w/out tubes, and see improved performance. Experiment. I like 2-3 lbs. less up front than in rear. I also like a completely different tire for each (front and rear), since I believe they are responsible for two totally different things. Weight also impacts tire pressure, as does conditions and what you expect from your tires.

    I like tubeless, and I find my sweet spot on my tires tends to be in the mid 20's. Your tires may be entirely different.

  96. #296
    mtbr member
    Reputation:
    Join Date
    May 2009
    Posts
    589
    140lb rider, 23lb FS bike, Norcal XC riding including some technical...

    Front: 20 psi, Nobby Nic 26x2.25 EVO Snakeskin
    Rear: 23 psi, Racing Ralph 26x2.25 EVO Snakeskin

    I run both tires tubed and have not come close to pinching. I can get away with really low psi as I am light and these tires can be run at ridiculously low pressures. Fantastic grip for dry summer conditions and the extra volume provides some nice cush. Front tire just rails and the rear tire tracks nicely, but still kicks out when needed.
    Last edited by Fiendbear; 07-10-2012 at 04:36 PM.

  97. #297
    unpossibles
    Reputation: Josh_SL2's Avatar
    Join Date
    Mar 2012
    Posts
    219
    255lbs on 2.1s running 30/30. I've run as low as 24/24 after forgetting to check pressure before a ride and felt the rim on a rock or two but no flats.

  98. #298
    mtbr member
    Reputation: raducanmihai's Avatar
    Join Date
    Mar 2009
    Posts
    6
    I used to be a 200 lbs XC rider on a hardtail and my pressure was 42 front/45 rear PSI. Now I weigh 170 lbs and I also changed my wheels to XT M785 (UST rim). I run tubeless front (RocketRon 2.25 Evo TLR) and tube-type rear (RocketRon 2.25 Evo TLR). The rear was also mounted tubeless but I cut it ,so I had to use a tube.Since my new wheelset and weight loss I droped the pressure to about 33f/35r. I would like to try really low pressures to see how it feels,but the instructions on the Shimano site says the pressure should be between 29 and 58 PSI.
    I read here about pressures as low as 18 PSI (front) and 22 (back). Would this kind of numbers void my wheel warranty or,at least,increase the risk of rim damage?

    PS: I will soon change the tires (or at least the damaged one) to WTB Bronson 2.1 TCS (mounted tubeless with Stan's) if this makes any difference.

  99. #299
    mtbr member
    Reputation: roaringboy's Avatar
    Join Date
    Aug 2009
    Posts
    194
    Problem i have is my regular ride features about 10 miles of road/paved tracks each way to and from the offroad stuff. Obviously you want higher pressures for the road and lower for offroad. I tend to try and find a happy medium which is about 30 front and 30-35 rear.

    If i'm driving to a trail i'll go 25-30 front and rear.

    Riding a 2.0 front and a 1.9 rear (both tubeless).

  100. #300
    mtbr member
    Reputation:
    Join Date
    Aug 2012
    Posts
    13
    180 lb rider 23 pound niner 23 psi 2.4 RR front 28psi RR rear tubeless

  101. #301
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    3,849
    the physics on tire contact patch is close enough, but technically doesn't conform exactly to the air pressure calculations, especially on wide rims or when using very stiff, heavy tires like UST.

    the reason is very simple: more than just air is actually bearing the bicycle & rider weight. it's the tire carcass.

    the carcass bears little weight using a 1.8" race-day-only semislick, but it bears a lot when you run a heavy tire on a p35. think about a runflat tire for a car. how does it bear the weight of the car with little to no air pressure?

    anyway, just food for thought. this is another one of the ways people run ultra-low pressure is by using a wide rim and a beefy tire.

  102. #302
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    1
    I am 185# rider and went with the 40# tire pressure and when I was about 8 miles from my truck when I got a pinch on both tires and bent my rear rim. I was on a down hill run with lots of rock. The week be for I was on smooth dirt and more of a flat trail and it worked great. so i think a lot has to do with your riding terrain.

  103. #303
    mtbr member
    Reputation: dhmoore's Avatar
    Join Date
    Aug 2012
    Posts
    13
    The other day, I had a long ride on the paved road with some pretty steep climbs before getting off-road, so I had the tires inflated to about 40#, thinking that this pressure would be low enough to handle sandy surfaces... I quickly realized as I left the pavement and hit a 15% grade, with hard dirt and a thick coat of sand, that I really wanted to have less pressure in the rear tire - it spun out and slipped very badly - but I didn't want to let the air out because I didn't have a lot of time before dark and I had a long ride back on the pavement.

    I've been thinking about getting a compressed-air cartridge-type tire inflator, but I'm not sure which one, and whether there are inflators that you can re-fill... I have DEFINITELY noticed widely varying performance with different tire pressures... Can somebody recommend the best way to quickly inflate/deflate and manage tire pressures while on the trail?

  104. #304
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    3,849
    it can feel 'funny' when riding on pavement with trail pressure, like you have a flat tire, but it's barely slower if you actually measure your speed and elapsed time. you will lose a lot more time getting off the bike to mess with the air pressure.

    I would get a high volume frame pump if you really insist on doing this.

  105. #305
    mtbr member
    Reputation:
    Join Date
    Aug 2011
    Posts
    68
    Can't believe I just read this whole thread...

    ...but I didn't read much about bent or dented rims. Are most of you able to go this low without worrying about your rims? I'm constantly thinking about them getting damaged.

  106. #306
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    6
    Quote Originally Posted by mr.niles View Post
    in fact i do have timing device coming in the mail! yeah, it's hard to tell! that's why it's confusing to me. i'm always changing my presuures around to try and figure out what is best. i will try lower pressures, but i'm just not sure where to start. any ideas?
    I can't remember where I read it, but recently I saw a formula for a base tire pressure from which you can adjust, depending upon your tires, trail type, conditions, etc. The formula was to divide your weight with helmet, shoes and backpack by 7. Subtract 1 lb for the front tire and add 2 lbs for the back tire.

  107. #307
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by dhmoore View Post
    I've been thinking about getting a compressed-air cartridge-type tire inflator, but I'm not sure which one, and whether there are inflators that you can re-fill... I have DEFINITELY noticed widely varying performance with different tire pressures... Can somebody recommend the best way to quickly inflate/deflate and manage tire pressures while on the trail?
    When I need to I carry a mini pump (like 150 grams) and a digital gauge (50 grams). Especially with a new bike/tires combo that I want to play with. Little weight, gives you insurance, reliable. When I ride with buddies one pump in the group is usually enough.

  108. #308
    mtbr member
    Reputation: dhmoore's Avatar
    Join Date
    Aug 2012
    Posts
    13
    Sounds H
    Quote Originally Posted by geeter View Post
    I can't remember where I read it, but recently I saw a formula for a base tire pressure from which you can adjust, depending upon your tires, trail type, conditions, etc. The formula was to divide your weight with helmet, shoes and backpack by 7. Subtract 1 lb for the front tire and add 2 lbs for the back tire.

    Hey, that sounds interesting.... I'd like to see this tire-pressure formula. I've been using the caveman method: grab tire and squeeze hard, if going uphill, it okay if very squishy... if going downhill, no want so squishy, especially if have innertubes... if no steep up and downs, make tire hard like rock so bike pedal easier.

  109. #309
    mtbr member
    Reputation:
    Join Date
    Aug 2012
    Posts
    2
    To all those who are resisting going tubeless as I was for years. I even had tubeless ready wheels and ran tubes, GO TUBELESS and don't look back.
    No More pinch flats. I weight 195 and like to ride technical trails with as much rocks, ruts, roots and jumps as I can find. With tubes I ran 34/36 psi with an occasional pinch flat, tubeless I now run 26/29 on 2.3/2.2 tires with no issues. I have run as low as 21/25 but I feel the sidewall flex too much. As far as trail repairs, carry a spare tube and co2 cartridges with a quality inflator. I also carry a small pressure gauge to check pressure and a small pump just incase.

    Best advice I was give regarding mountain biking was to go tubeless.

  110. #310
    mtbr member
    Reputation: raducanmihai's Avatar
    Join Date
    Mar 2009
    Posts
    6
    Quote Originally Posted by dhmoore View Post
    Sounds H


    Hey, that sounds interesting.... I'd like to see this tire-pressure formula.
    It is on Stan's NoTubes site.

  111. #311
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    3,849
    That formula is linear and as such I doubt it will work well for light and very heavy riders. A 115 pound woman can ride 15F/17R psi, really?

  112. #312
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by raducanmihai View Post
    It is on Stan's NoTubes site.
    Damn, you beat me to it.

    In my experience, its been closer to (weight/7)+3 in front, and (weight/7)+7 in rear, but I'm also suspicious of the readings on my floor pump. Its 10 years old and I have not found 35 psi from others peoples' pumps to feel like 35 psi from my pump. I end up running 31 f/35 r. Your experiences may vary

    Quote Originally Posted by ColinL View Post
    That formula is linear and as such I doubt it will work well for light and very heavy riders. A 115 pound woman can ride 15F/17R psi, really?
    I'm a 200 lbs Cat 1 SS mtbr, so I think my tires have their work cut out for them .
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  113. #313
    mtbr member
    Reputation: ghettocop's Avatar
    Join Date
    Jul 2011
    Posts
    1,434
    Here is a cool app by Geax.....Bead seat diameter, tire type, type of riding, rider weight, etc....will calculate the lowest pressures you can run.


    iTire Pressure ę Geax.com

  114. #314
    mtbr member
    Reputation: dhmoore's Avatar
    Join Date
    Aug 2012
    Posts
    13
    Thanks raducanmihai n ZXFT... kewl stuff! :]

    Holy COW, ghettocop! Dude! That's a VERY kewl app!

    I was goofing with my pressures on a steep, rocky, ascent the other day and lowered the pressure waaaaaay down so the rims were bumping the rocks (tubless)... SERIOUS improvement in traction and much, much smoother climb... I knew lower pressure was better for climbing, and run low pressure, but not this low - like fifteen pounds! haha did it just to see how low I could go... then put a few more pounds in and climbed some more... then again, and let some out... got it just right, but didn't have a pressGuage with me to record the exact pressure... on the descent I pumped 'em back up again several pounds more for the extra impact and stability at higher speeds... gotta get a guage... as I was riding, I was thinking "yea, one of these days we'll probably have a guage and a controller on the handlebars with a pressure adjustment while riding" wouldn't THAT be kewl!

  115. #315
    mtbr member
    Reputation: Tillers_Rule's Avatar
    Join Date
    Sep 2004
    Posts
    581
    Historically:

    50F/50R
    35F/45R

    Now I'm at 35F/40R. I've found anything less in the rear and the tire distorts too much, I can go a bit less in the front but this combo seems ideal for me for now. I'm 215 loaded up. Picking up a new bike here, a 29", so I'll get to play with PSI again!

  116. #316
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by ZXFT View Post
    In my experience, its been closer to (weight/7)+3 in front, and (weight/7)+7 in rear, but I'm also suspicious of the readings on my floor pump. Its 10 years old and I have not found 35 psi from others peoples' pumps to feel like 35 psi from my pump. I end up running 31 f/35 r. Your experiences may vary
    Quick update, I tried 29f/32r with a new floor pump (since my old one broke ) and it felt very similar to my previous 31/34. I'll keep messing with pressure and see if I cant get it down to the stans formula.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  117. #317
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by ZXFT View Post
    Quick update, I tried 29f/32r with a new floor pump (since my old one broke ) and it felt very similar to my previous 31/34. I'll keep messing with pressure and see if I cant get it down to the stans formula.
    2 PSI is well in the margin of error of floor pump gauges. Mine pump gauge has 5PSI difference than the other gauges which I believe are more accurate (one mechanical and one digital, both reading within 0.5SPI of each other)

  118. #318
    mtbr member
    Reputation:
    Join Date
    Aug 2012
    Posts
    17
    So after skimming through this entire thread my head is spinning. I came on here looking for info because during trail riding my rear tire is spinning on steep climbs and the bike is bouncing around too much on descents. Obviously the psi im running is too high.

    Just for clarification...as the tire pressure drops what are you gaining and losing? Does a lower pressure provide more traction/braking or are you going to corner better?

    This thread has been very informative. Thanks!
    Last edited by Criswell; 08-19-2012 at 09:56 PM.

  119. #319
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by Criswell View Post
    Does a lower pressure provide more traction/braking or are you going to corner better?
    Both. Assuming its not so low that your tire squirms in corners.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  120. #320
    Dab-O-Matic
    Reputation: Simplemind's Avatar
    Join Date
    Jul 2006
    Posts
    1,038
    Quote Originally Posted by ghettocop View Post
    Here is a cool app by Geax.....Bead seat diameter, tire type, type of riding, rider weight, etc....will calculate the lowest pressures you can run.
    iTire Pressure ę Geax.com
    Muchas Gracias! Great app.(I like no brainer concrete answers, even if it's slightly off )!

  121. #321
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,794
    Quote Originally Posted by Criswell View Post
    So after skimming through this entire thread my head is spinning. I came on here looking for info because during trail riding my rear tire is spinning on steep climbs and the bike is bouncing around too much on descents. Obviously the psi im running is too high.

    Just for clarification...as the tire pressure drops what are you gaining and losing? Does a lower pressure provide more traction/braking or are you going to corner better?

    This thread has been very informative. Thanks!
    Keep in mind rear suspension setup matters too.

  122. #322
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Generally, with lower pressure:

    Gain traction (cornering, braking, climbing)
    Bike is little more vague
    Bike rides more plush (less bounce, especially on a hard tail)
    Less rolling resistance on rough terrain
    More rolling resistance of flat terrain
    More prone to pinch flats (tubes)
    More prone to rim damage
    More prone to burping and tire rolling off the rim (tubeless)

    I think thats about it?

  123. #323
    mtbr member
    Reputation:
    Join Date
    Aug 2012
    Posts
    1
    I am a 190-200 pounder excluding the 20 pounds of equipment, water and stuff on me and run 1.6bar soft front and 2 (very stiff) back tubeless onloose sharp rocky track. I need advise on the sort of tyres though since I have shredded two back tyres in the last two months - the last was a Scwalbe Rocket Ron EVO 26" and besides 7 pinky sized holes I fixed an inner and then after some 50K's popped went the sidewall - was this just bad advise from my shop since i run the same in front with no problem in the past year+? I now switched to Continental Speedking 2.2 which apparantly has thicker sidewalls. So far ok besides one small puncture that sealed up quick and Stans leaking small bits all the time from the valve and rim edge. Did not loose much pressure on yesterdays 50K run. I must add that the rim took a knock and bent when I hit a rock but it is almost 98% good but for a small wobble. Should I rather convert my backwheel to downhill rims, hub and tyres? Or will this be SO much heavier?

  124. #324
    ONE speed under God.
    Reputation:
    Join Date
    Jul 2012
    Posts
    190
    This is a great thread... Except it looks like I wasted $80 on my new set of Geax barro race 2.0s. This is a low volume tire and I weigh 252 or so. I suspect a few of you will tell me to ditch them.

    They're actually very good tires, and def better than my Nanos on the dirt. I've only ridden them twice on the trail tho, and the both rides were muddy - after the rain rides so they've not been fully tested yet. I'm running 28/30 right now, and don't think I should go much lower as I am a big MF-er.

    My question is - would it be a good setup to go with a 2.3 tire in the front and leave the Geax in the rear? I'm not gonna put one of the Nanos back on as it's already been proven that they suck on the loose stuff.
    Nashbar SS 29er
    K2 FS Attack
    Cannondale R600

  125. #325
    mtbr member
    Reputation: ewise's Avatar
    Join Date
    Nov 2010
    Posts
    23
    Throwing my experience into the mix.
    I weigh about 160-165# in full gear. I am running 2.25 Nobby Nic front and 2.25 Racing Ralph on back. Both are the TL-Ready, SnakeSkin version. I have put two scoops of Stans in each. They just work. I am running these on 26" XTR Trail wheels.

    I have been riding these tires at between 19-22# F and 20-23# R and did the BC Bike Race at this tire pressure. They were a little soft/squishy on the roads but they just worked.

    I also ride fairly hard on a wide variety of terrain (steeps, rocks, smooth, sandy) with no problems (burps, air loss). That said, I am also fairly good at line selection and we don't have much in the way of sharp exposed rocks in Whitehorse.

    The bead locks onto the rim and it's a bugger to break when I have to replace the Stan's (just did). It literally glues into place.

  126. #326
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by ewise View Post
    The bead locks onto the rim and it's a bugger to break when I have to replace the Stan's (just did). It literally glues into place.
    What I do is lay the wheel flat on the ground, and step on the tire close to the rim. With all your body weight on it the tire will separate from the rim, so far it worked every time and super easy. Once it separates in one point a tire lever can do the rest, and if not, step again on the trouble spot.

  127. #327
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    15
    my weight is 225lbs i ride a '09 specialized rockhopper expert im new to riding what pressure is recommended for me? im new to all this mountain biking by the way.

  128. #328
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by mr_z View Post
    my weight is 225lbs i ride a '09 specialized rockhopper expert im new to riding what pressure is recommended for me? im new to all this mountain biking by the way.
    What tires? Size is a major factor.

  129. #329
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    15
    26 x 2.00" specialized fast trak.

  130. #330
    I like bacon... (clyde)
    Reputation: SpyderPride's Avatar
    Join Date
    Jul 2008
    Posts
    351
    Quote Originally Posted by mr_z View Post
    26 x 2.00" specialized fast trak.
    Try 30 front, 35 rear. If it feels squirmy (you'll know it when you feel it) or you pinch flat, bump it up 3-5 psi on the tire that is giving you issues until the problem goes away. I am nearly your weight with similar width tires, albeit a different tread style, and that's what I would do.

    Sent from my ADR6410LVW using Tapatalk 2
    Bike: '08 Trek 6500
    Color: Oreo
    Delicious...

  131. #331
    mtbr member
    Reputation:
    Join Date
    Aug 2012
    Posts
    29
    Quote Originally Posted by geeter View Post
    I can't remember where I read it, but recently I saw a formula for a base tire pressure from which you can adjust, depending upon your tires, trail type, conditions, etc. The formula was to divide your weight with helmet, shoes and backpack by 7. Subtract 1 lb for the front tire and add 2 lbs for the back tire.
    That was helpful. Thanks.

  132. #332
    mtbr member
    Reputation:
    Join Date
    Aug 2009
    Posts
    380
    I weigh 180 fully loaded with 3L of water in my Camelback. Running Hans Dampf 26x2.35 in front at 24 psi and Racing Ralph 2.25 in the back at 26 psi.

  133. #333
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    1
    I probably weigh 180 lbs loaded up. Still learning about tires. Limits are sliding off roots on a turn due to too high a pressure, 40 lbs or so. Let out air until a finger squeeze dents the side of the tire. Before I went tubeless rims, just converted-tubeless, it was like gaining a gear, rolling friction much better. Squirm on corners is creepy after a couple of gulp flats throw you down. Switched to foldable tubeless on tubeless-clincher rims, a much stiffer tire without squirms or gulps, gaining back some tire friction. Feels solid.

    Bought a tire gauge and decided to run rated minimum of 30 lbs, but tire like a rock slipping on every flat stone and root. Started letting air out to gain secure grip on rocks and roots. Now they look slightly flatter and fatter on the bottom, squeeze test ok. Maybe if I think about it ahead of time I'll pump up on the electric pump at home to cut down on rolling resistance on the long miles, and then when I reach the trail, or large rocks on the road, I'll let out air when I unlock the front shock (w/hardtail), tuning pressure it down until it feels secure. I sure don't want a gulp flat, but those new clinchers really lock in, and I've had no flats, squirms or gulps since I went legit.

    Of course, I've been really cautious about getting too low and have pumped up on the trail when it feels too soft. The last thing I want to do is go down on a gulp in a tight turn (have done) the bruises, road rash and near death experiences are not part of the fun. Part of getting older is slowing down knowing you're not as invulnerable as your glands lead you to believe. Having your life flash before your eyes is not for me now, or later.

    I would like a lower pressure gauge as nothing over 40 lbs is of interest to me, and my 160 lb AccuGauge is not very useful in tuning lower pressures. Got any suggestions? I'll trade you a nice gauge for something easier to read at low pressures.

  134. #334
    mtbr member
    Reputation:
    Join Date
    Nov 2005
    Posts
    32
    After 20 years of riding tires from 45-65 psi, I finally read this thread. I'm 6'0, 195 lbs with gear. Just got done riding my Spesh Epic 29er EVO with 30psi front and back... life changing. Tearing through rock gardens like a fat kid chasing an ice cream cone. No bottoming or pinch flats.

    Can't wait to try even lower pressure.

  135. #335
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    329
    Quote Originally Posted by Schroedinger View Post
    After 20 years of riding tires from 45-65 psi, I finally read this thread. I'm 6'0, 195 lbs with gear. Just got done riding my Spesh Epic 29er EVO with 30psi front and back... life changing. Tearing through rock gardens like a fat kid chasing an ice cream cone. No bottoming or pinch flats.

    Can't wait to try even lower pressure.
    People like you are rare. Most people if they've been doing it one way for 20 years thats the "right way" to do it. Good job on having an open mind.
    Something wrong with your bike? Blame it on super human strength and sleep well at night knowing you are more than a man.

  136. #336
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    1,475
    I weigh 200 lbs (not including camel back stuffed with tools & water) and run 32 psi front and back on my stumpy fsr. I have never had issues with flats or pinch flats, I tried 30 & 28 on a variety of tires and they felt too squirmy for my weight along with pinch flats.

  137. #337
    I like bacon... (clyde)
    Reputation: SpyderPride's Avatar
    Join Date
    Jul 2008
    Posts
    351
    Quote Originally Posted by stumpynerd View Post
    I weigh 200 lbs (not including camel back stuffed with tools & water) and run 32 psi front and back on my stumpy fsr. I have never had issues with flats or pinch flats, I tried 30 & 28 on a variety of tires and they felt too squirmy for my weight along with pinch flats.
    What tires are you using and how wide are they?

    I am currently 215 without gear, running a 2.4 X-King front at 28 psi and a 2.2 Race King rear at 30 psi. I have narrow rims (17 inside) but would like to go lower as I haven't felt any squirm cornering, but the issue is that the tires tend to slide in the rim and tear off valve stems. This is currently remedied with gorilla taped beads but I don't want to push it. Oh how I wish I would have bought wider rims...

    --
    Sent from my DROID Incredible 4G LTE using Tapatalk 2
    Bike: '08 Trek 6500
    Color: Oreo
    Delicious...

  138. #338
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    1,475
    Im running 2.2 captains currently with American Classic MTB rims, Im not sure how wide they are but 32 psi works best for me on a wide variety of terrain.

  139. #339
    mtbr member
    Reputation: bikeface.killa's Avatar
    Join Date
    Oct 2012
    Posts
    16
    I usually ride the rear tire around 20psi. I'm 145 and ride technical single track with a lot of baby heads. I am riding tubeless 2.0 on 29er rims. Up front I run about 23 on 2.2s

  140. #340
    Kick Start My Heart
    Reputation: davez26's Avatar
    Join Date
    Dec 2004
    Posts
    567
    Quote Originally Posted by Schroedinger View Post
    After 20 years of riding tires from 45-65 psi, I finally read this thread. I'm 6'0, 195 lbs with gear. Just got done riding my Spesh Epic 29er EVO with 30psi front and back... life changing. Tearing through rock gardens like a fat kid chasing an ice cream cone. No bottoming or pinch flats.

    Can't wait to try even lower pressure.
    Yeah, sounds stupid, but I've gotten this old and I am just now toying with pressures on both the Road and MTB, and the results are eye opening.
    I am so old school I still run the Smoke/Dart combo. I am feeling good at 25F/30R and it's been awesome. I may go a little less, just to see. I am going by the rule, 'keep reducing until you snake bite, then add 5'
    We will see.

    Sent via psychic suggestion....on Tapatalk.

  141. #341
    mtbr member
    Reputation: BDozer's Avatar
    Join Date
    Mar 2012
    Posts
    74
    I weight about 185lbs load up, bike is a 26lbs FS. Currently running 35/35psi ft/rr on Specialized Specialized "Fast Trak" Armadillo 2Bliss ready 26x2.00 ft and Specialized "The Captain" Armadillo 2Bliss ready 26x2.00. Both currently with tubes with sealant. I hate flats.

    Plan is this winter to change to something wider (2.25-2.4) and go tubless. Also will buy an accurate pressure gage. Then I'll experiment with which pressure is the best compromise for the range of surfaces I run on (pavement to lose rock/dirt climbs).
    Last edited by BDozer; 10-27-2012 at 08:16 PM.

  142. #342
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    12
    I have 2.1" tires (I think--It says 26x2.1 on my tires (I'm kinda new to MTBing)) and I weigh 125 lb, so what kind of PSI should I use (or how low could I go)? On the tires it says the min PSI is 40 and the max is 65. I do XC mostly.
    Thanks!
    Also, everyone is saying "keep lowering it until you get pinch flats" but isn't that at all bad for the tire and/or tube to keep puncturing holes in it/them?

  143. #343
    mtbr member
    Reputation:
    Join Date
    Oct 2006
    Posts
    2,790
    Quote Originally Posted by Ferrari353 View Post
    ...Also, everyone is saying "keep lowering it until you get pinch flats" but isn't that at all bad for the tire and/or tube to keep puncturing holes in it/them?
    You may ruin a tube but probably won't hurt the tire while figuring it out (you're not going to be pinch flatting every ride over and over). At only 125# I'd start with ~32psi and go from there.

  144. #344
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by Ferrari353 View Post
    Also, everyone is saying "keep lowering it until you get pinch flats" but isn't that at all bad for the tire and/or tube to keep puncturing holes in it/them?
    I wouldn't say lower until you get pinch flats. There are many other reasons to stop lowering. In my terrain the tires will start to squirm in turns and feel like you are riding on gello before they flat. In a tubeless setup they can also roll off the rim in low pressure. Not to mention flat spotting your rim or getting too many dings and scratches. All are reasons not to go too low.

    But for your original question, after a pinch flat the tube can be toast, because the cuts can be long. Tires seem to care less.

  145. #345
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    12
    Quote Originally Posted by gmcttr View Post
    You may ruin a tube but probably won't hurt the tire while figuring it out (you're not going to be pinch flatting every ride over and over). At only 125# I'd start with ~32psi and go from there.
    That seems like you'd be wasting a lot of patches fixing the pinch flats. I'll try 32 and see how it rides. If it doesn't feel right (or like jello), then I'll raise the PSI.
    Thanks for the advice guys!
    Quote Originally Posted by CrozCountry View Post
    I wouldn't say lower until you get pinch flats. There are many other reasons to stop lowering. In my terrain the tires will start to squirm in turns and feel like you are riding on gello before they flat. In a tubeless setup they can also roll off the rim in low pressure. Not to mention flat spotting your rim or getting too many dings and scratches. All are reasons not to go too low.

    But for your original question, after a pinch flat the tube can be toast, because the cuts can be long. Tires seem to care less.

  146. #346
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    6
    Here's the rule of thumb I've always used. I've never had a accurate gauges on any of my pumps, so I take the tire and "bounce" my weight down on it with the narrow outside of my palm. I should just barely be able to feel the rim when I bottom out on the front wheel. A tiny bit more pressure than that for the back.

    This is for a rigid bike with 2.4" tires, tubes, and rhino lite rims.

  147. #347
    mtbr member
    Reputation:
    Join Date
    Nov 2009
    Posts
    1,964
    I am running 29x2.3 Renegades on Crest rims at 15 psi front and rear with tubes, on a HT. I weigh 155. No problems yet, and they don't feel squirmy. When I first got these tires I aired them to 20 psi (which is what I was running my 29x1.95 Renegades at) and they were way too bouncy. Next tried 17 psi which was a bit better, but not quite what I was hoping for. 15 psi pretty much hit the spot. My home trails are relatively rocky, however I have been riding them for years and I am a somewhat smooth rider.

    I'd like to get a separate gauge to confirm these pressures since I would not have guessed that I'd be running them and I am pretty surprised.

  148. #348
    Mulleticious
    Reputation: BigwheelsRbest's Avatar
    Join Date
    Jun 2007
    Posts
    1,494
    What I have noticed is that the wider the tire, the lower the pressure I can get away with.

    This leads me to another question - what is the widest tire people are running on Crest rims? I am currently on Nobby Nic 2.25" (at 17 psi) and want to go wider, but don't want problems with squirming...

  149. #349
    mtbr member
    Reputation:
    Join Date
    Nov 2009
    Posts
    1,964
    Quote Originally Posted by BigwheelsRbest View Post
    What I have noticed is that the wider the tire, the lower the pressure I can get away with.

    This leads me to another question - what is the widest tire people are running on Crest rims? I am currently on Nobby Nic 2.25" (at 17 psi) and want to go wider, but don't want problems with squirming...
    I think that the Crests are fine with that. I'm pretty sure I came across a Notubes forum question where the Notubes guy said the Crests could definitely handle a 2.3. I'll see if I can find it.

    Crests are 21 inner width, so they're in my opinion and experience pretty suited at running wider tires.

    I had been running 26x2.4 X-king's on my Bontrager RXL's which are the standard 19mm width, and to me, they always felt fine. I also ran those with tubes. They were the first generation Racesports and sealing them up was a PITA so I just gave up and used tubes. Blew my mind how well they rode and how low I could go with the pressure (around 20-21) and changed my mind about running skinnier tires.

    I recently bought some of the X-king's in 29x2.2 in the RTR Protection version. Unpackaged one, put it on an aired it up, and it was way small...smaller than the Renegades at 1.95. Returned 'em. Hoping Conti actually starts delivering that tire in 2.4,

  150. #350
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    67

    rigid/hardtail/full sus variable?

    ~200#'s geared up. I've been running Stan's Flow rims and Panaracer Rampages 2.35's, front and rear, on a rigid steel SS and a Yelli Screamy hardtail.

    As many posters before, I go as low as I can on Pac. NW trails without rim striking or feeling too squirrelly. The low pressure obviously helps with traction, and also with the cush of the ride. I think I'm usually at 18-23 front and 20-25 rear. If I have to ride pavement for a long stretch, I'll inflate.

    Here is my question. I do not think it has been addressed directly yet.
    How does tire inflation and suspension, specifically FS, interface?

    After a season of only having my rigid and HT I have just built a 650 SC Blur XC and am therefore thinking about this.

    Does it make sense to run a bit higher psi with a FS bike, in order to better engage the suspension?
    I imagine that there is an optimal psi where the cush in the tire works in concert with the suspension--where they are balance in the same way we need to balance front and rear suspension in a bike.

    When I had a full suss before (a Rip9) I ran the tires as low as I did on my rigid and HT, but I always wondered about the tire psi/FS relationship.

    Anyone have an opinion?

  151. #351
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    3,849
    You would run the FS bike at the same pressures for a given tire as the HT bike, like you said. I see a lot of people running huge tires on rigid bikes to get max air volume tires to run them as low pressure as possible, in order to get a better ride. But that's of course nothing like full suspension.

    You may not need higher pressure in a fast-rolling tire on pavement or gravel roads. I have not noticed any real difference between my trail pressure, 25F/27R, and running 5 psi more for the road. This is on a fast tire, a Geax Saguaro 2.2F/2.0R. On other tires, especially slow rolling tires, the difference was more significant.

  152. #352
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by daniel harvey View Post
    ~200#'s geared up. I've been running Stan's Flow rims and Panaracer Rampages 2.35's, front and rear, on a rigid steel SS and a Yelli Screamy hardtail.

    As many posters before, I go as low as I can on Pac. NW trails without rim striking or feeling too squirrelly. The low pressure obviously helps with traction, and also with the cush of the ride. I think I'm usually at 18-23 front and 20-25 rear. If I have to ride pavement for a long stretch, I'll inflate.

    Here is my question. I do not think it has been addressed directly yet.
    How does tire inflation and suspension, specifically FS, interface?

    After a season of only having my rigid and HT I have just built a 650 SC Blur XC and am therefore thinking about this.

    Does it make sense to run a bit higher psi with a FS bike, in order to better engage the suspension?
    I imagine that there is an optimal psi where the cush in the tire works in concert with the suspension--where they are balance in the same way we need to balance front and rear suspension in a bike.

    When I had a full suss before (a Rip9) I ran the tires as low as I did on my rigid and HT, but I always wondered about the tire psi/FS relationship.

    Anyone have an opinion?
    Tire pressure is part of the setup with suspension, hardtail or fully. I have needed to change tire pressures for suspension bikes compared to what I used on a rigid bike. Change the suspension settings and have found I needed to adjust the tires again. How I changed the pressure varied with the specific tire and the suspension type. With some other tires it does not seem to matter what type of bike they are on.

    I have also used tires that worked terribly on a rigid bike no matter the pressure. Moved them to a suspension bike and they were brilliant.

    All goes back to the basic answer for this thread: you need to experiment and see what works best for you, your terrain, setup and riding style.
    mtbtires.com
    The trouble with common sense is it is no longer common

  153. #353
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by daniel harvey View Post
    Does it make sense to run a bit higher psi with a FS bike, in order to better engage the suspension?
    I imagine that there is an optimal psi where the cush in the tire works in concert with the suspension--where they are balance in the same way we need to balance front and rear suspension in a bike.
    I run a few more PSI on the hardtail rear tire to reduce the chance of pinch flats (comparing to equivalent tire on FS).

  154. #354
    mtbr member
    Reputation: JoeJITSU's Avatar
    Join Date
    Jan 2013
    Posts
    41
    So I just recently came from a ride here in Las Vegas and this trail has rocks pretty much everywhere. I decided to go tubeless and I think the pressure was at 40-45 on front and back. I am running Nevegal Crossfires 26x2.1 on the back. I got a "burp" riding on the ridge of a boulder, So I go and pump it back up not having a gage I just went by feel. About 2 miles later, I hit a pretty good rock and that was that. I go into my pack and look at my tube, Oh my god...Tube I bought had the wrong valve, I thought I bought a presta valve. My wife who rode with me was pretty pissed, We were 5 miles in , in the middle of the desert, Thank god there was a person that passed me off a 29er tube and I put in on my 26er and rode back safely.
    Now I think it had a lot to do with me being 220lbs. I will stick to tubes till I lose about 25-30 more lbs.

  155. #355
    mtbr member
    Reputation: borbntm's Avatar
    Join Date
    May 2011
    Posts
    615
    Quote Originally Posted by JoeJITSU View Post
    So I just recently came from a ride here in Las Vegas and this trail has rocks pretty much everywhere. I decided to go tubeless and I think the pressure was at 40-45 on front and back. I am running Nevegal Crossfires 26x2.1 on the back. I got a "burp" riding on the ridge of a boulder, So I go and pump it back up not having a gage I just went by feel. About 2 miles later, I hit a pretty good rock and that was that. I go into my pack and look at my tube, Oh my god...Tube I bought had the wrong valve, I thought I bought a presta valve. My wife who rode with me was pretty pissed, We were 5 miles in , in the middle of the desert, Thank god there was a person that passed me off a 29er tube and I put in on my 26er and rode back safely.
    Now I think it had a lot to do with me being 220lbs. I will stick to tubes till I lose about 25-30 more lbs.
    I am right at 215lbs, run Stan's Arch wheel set, sealant and Nobby Nic tires running between 20 and 30 psi with no issues, it may just be the combo of wheel / tire causing your issue?

    I have also heard of tires blowing off with psi to high, 40 could be to high with your combo, try a lower tire pressure??

    It would suck for me to have to go back to tubes! Good luck....

  156. #356
    mtbr member
    Reputation:
    Join Date
    Jan 2013
    Posts
    347
    I've read a couple of pages of this thread, but not all of them.

    My new bike is tubeless from the LBS. I went from 35 to 30 psi. Tonight I tried 25 psi. Wow! I could hold tight corners that I used to slide on. I could also keep traction if I ran towards the edges of the trail and accidentally hit duff. So my question: is there any risk of burping tires and having a major blowout if I run lower pressures?

    I'm running Ground Control 2Bliss 2.1s (stock on Speci Carve 29er HT). I weigh probably 190# with all my gear and the bike weighs 26#. Trails are not particularly technical -- mostly slightly damp hardpack with many roots and some mud (not deeper than the tire). On a scale of 1 to 5, 5 being the most technical, I'd rate them a 2.

  157. #357
    Happy Trails
    Reputation: Scott In MD's Avatar
    Join Date
    Sep 2008
    Posts
    1,189

    Tire pressure for all around XC riding?

    Lower. And lower.

  158. #358
    mtbr member
    Reputation: CrozCountry's Avatar
    Join Date
    Mar 2011
    Posts
    1,580
    Quote Originally Posted by Gregon2wheels View Post
    Tonight I tried 25 psi. Wow! I could hold tight corners that I used to slide on. I could also keep traction if I ran towards the edges of the trail and accidentally hit duff. So my question: is there any risk of burping tires and having a major blowout if I run lower pressures?

    I'm running Ground Control 2Bliss 2.1s (stock on Speci Carve 29er HT). I weigh probably 190# with all my gear and the bike weighs 26#. Trails are not particularly technical -- mostly slightly damp hardpack with many roots and some mud (not deeper than the tire). On a scale of 1 to 5, 5 being the most technical, I'd rate them a 2.
    Yes there is risk. I rolled a tubeless tire completely off the rim on a bad landing when the front was not straight. There is also a compromise in handling in lower pressure. Looks like you are around your sweet spot. I wouldn't go much lower than that, and always carry a spare tube with you in case it happens. It really depends on the trails and your riding style. Rocks and roots increase the chance of a burp, jumps, drops and high speed turns as well.
    I now run around that pressure and I weigh little less and use fatter tires, after I put a couple of nice dings in the rims.

  159. #359
    mtbr member
    Reputation:
    Join Date
    Jun 2004
    Posts
    64

  160. #360
    mtbr member
    Reputation: rocksolid's Avatar
    Join Date
    Oct 2010
    Posts
    123
    Great link,could exsplain why i had a front tire blow.

  161. #361
    mtbr member
    Reputation:
    Join Date
    Jan 2013
    Posts
    208
    I'm back on this "lower pressure" approach after discovering it on my own way back when. This is a good discussion for validation!

    The odd thing I've found in recent years was that many bike shops, tire manufacturers, tire reps, floor pump instructions, etc. recommend the higher pressures -- the range of 35psi to 60psi depending on rider weight! It had made me think that my "lower pressure" approach was amateurish with no scientific basis for a better ride. That it was just psychological.

    Designers of tire tread, I was once told, do not design them for 20psi riding. Not even for 25psi. This is why, I was told, the sidewalls are stamped with the range of something like 35psi to 65psi. And these are 2.1 29" knobby!

  162. #362
    mtbr member
    Reputation:
    Join Date
    Jan 2013
    Posts
    208
    Quote Originally Posted by malariavalley View Post
    It recommends 30psi front and 33psi rear for me.

  163. #363
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    I'm still searching for optimal pressures on my MTB. On my cyclocrosser on the same tracks, I run 45f/70r on 33mm Maxxis Razes. Racing, that goes down to 40f/60r.
    Those pressures were come across after using Sheldon Brown's tyre pressure page for a baseline. 15% drop when loaded and then tune for the conditions. Which would indicate about 30f/35r for 88kg on 2” tyres as a start point.

  164. #364
    mtbr member
    Reputation: Bemiller's Avatar
    Join Date
    Jun 2013
    Posts
    51
    After having read through all 15 pages of this thread my head is spinning. I am new to mountain biking and am currently doing single-track, technical uphill/downhill through the rocky woods of CT.

    I have a Cannondale Moto2 at 35.5 lbs and my weight w/ gear is almost 160 so full weight on tires is 195.5 lbs.

    I am riding (tubes) Kujo DH 26x2.35" rear and Specialized Clutch SX 26x2.5" in front. I have been riding w/ 30-32psi in both tires but it seems, from what I have read, that I should be lower. I will definitely be adjusting my tires for tomorrow's ride but just would like a ballpark suggestion from some experts here.

  165. #365
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    I'd go 3-4psi lower both ends and work from there.

    I'm not fast at all and weigh 180 odd plus gear and am running 28f/30r on 2.0Ē tyres.
    Last edited by NordieBoy; 07-30-2013 at 11:19 PM.

  166. #366
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    4,971
    Time your rides. Sometimes a ride can "feel" fast, but time out slow. I've done this to adjust pressures and it works well over the long term. I have also found that different tires may work better at different pressures even though they are the same size. For example, a UST and "Racesport" version of the same tire at the same size work best at different pressures.

  167. #367
    mtbr member
    Reputation:
    Join Date
    Jul 2009
    Posts
    429
    Just go by feel. Ride what makes you feel confident, provided you're not burping tires or pinch-flatting. I did it this way and in the end found that my pressures were exactly what the calculator recommended for me.

    Bonucing off of rocks and roots? Lower the psi.
    Squishy feel, pinch flats or the tire coming off the rim? Raise the psi.

  168. #368
    mtbr member
    Reputation: go-pirates's Avatar
    Join Date
    May 2006
    Posts
    731
    Geax Seguaro 2.2's, 29". 24 psi, front and rear. 210 lbs. Works for me, with no issues. Has a nice supple feel, and I do not notice any squishiness.
    "Caught my first tube this morning....sir!"

  169. #369
    mtbr member
    Reputation:
    Join Date
    Aug 2013
    Posts
    883
    175lb to 180lb, sometimes 185lb. Concrete, just below max rated on both tires. Back, Dirt; 35psi to 45psi, sometimes 50psi, depending on terrain, density of soil and/or mud. Front, dirt; 48psi, unless using 50pis+ on rear--again, dependent on soil conditions--.
    Goodbye '95 ZJ. Just so you know, transfering box of left behind womens panties to next truck. Thank you ZJ!

  170. #370
    mtbr member
    Reputation:
    Join Date
    Jun 2012
    Posts
    245
    Never more than 33 in the back and 29 out front. I am 180-185 geared up and deal with a good amount of sharp rocks at high speed on every ride. The only flat I have had in the past 4 years was from running over 35 in the back... My strava times have shown me over and over again that low pressures are significantly faster for the areas I frequent. By the way, I use a maxxis freeride tube in the back with a 2.25 exo ardent, and a 2.1-2.4 DH tube up front that came on my slayer with a 2.4 HR2 or sometimes a 2.25 ardent up front. I do ride more AM than XC but the pressure doesn't change between the two I like to set and forget.

  171. #371
    mtbr member
    Reputation:
    Join Date
    Feb 2006
    Posts
    1,740
    such a subjective question with too many variables; Tires, tread, tread width, sidewall thickness, rubber durometer, terrain, rider weight, etc.

    Nonetheless I ride tubeless 28 or so rear, 26 or so front. works for me with my local rocks.

  172. #372
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    31
    I was thinking about this whilst switching tyres today. On the sides they had the usual 35-60 psi range and I honestly don't think I've ever ridden with either tyre at even the bottom part of that range for anything other than testing. The only time I ever tend to put 30+psi in my rear tyre is when I know that the trail is going to be without technical sections.

    I did recently try a few loops around a local cycle path and I lost about 5 minutes (over an hour) with higher pressures as I couldn't get the power down properly on the gravelly ascents. Dropping the rear to about 32psi stopped the bike feeling like it was bouncing around (on a relatively flat surface!) and I was definitely quicker.

  173. #373
    mtbr member
    Reputation: RSAmerica's Avatar
    Join Date
    Aug 2012
    Posts
    377

    Tire pressure for all around XC riding?

    I run 19 front / 23 rear with 2.35 x 650b tubeless on my hardtail. I weight ~155lbs. Try what Stan's says. Divide your weight by 7 and take off 1-2 psi front and add 1-2 psi in the rear.

  174. #374
    mtbr member
    Reputation:
    Join Date
    Sep 2011
    Posts
    37
    165 lbs and have been experimenting with a 2.35 Hans Dampf SnakeSkin front and a 2.2 Geax Saguaro TNT rear for snow riding on my rigid 29er, Haven UST rims. 22 psi rear rides well without looking like it is completely flat while 18 psi front is as low as it will go without burping and even lower would be better.

    One thing I've noticed with the Saguaro is that the direction of the tread makes a very noticeable difference. I switched it to the "traction" direction and suddenly the back end slides out sideways much more easily while cornering and using the rear brake.

  175. #375
    mtbr member
    Reputation:
    Join Date
    Jan 2012
    Posts
    4,572

    Tire pressure for all around XC riding?

    Running around 18 to 20 front and about 21 to 23 back on 29ers. I weigh 165 geared up.

    I meet a guy running 65 on a 26er the other day and I don't see how he gets any traction. I'll be toast down hill and could climb much either.

  176. #376
    mtbr member
    Reputation: engrmariano's Avatar
    Join Date
    May 2011
    Posts
    173
    200lbs 2.4 x-king 18 & 20 psi
    PIVOT

  177. #377
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    572
    That MTB Tech site was pretty helpful. I still run about 2-3psi lower than they say, but I know I am in the zone. I really just go by feel, but make note of the pressure when I hit the sweet spot.

    The site also confirmed my experience which is that low pressure on a 26Ē is different than a 29Ē. I have both and run the 26Ē (tubeless on WTB Frequency i19 rims with Geax Akas) at about 27/28 and it feels great. But I run the 29er a good deal lower at 24/25 to get the same feeling (tubeless on Stanís Arch rims and Maxxis CrossMark). Overall, I like the feel of the Aka the best, but it wears REALLY quickly.

  178. #378
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619

    Re: Tire pressure for all around XC riding?

    Quote Originally Posted by wahday View Post
    That MTB Tech site was pretty helpful. I still run about 2-3psi lower than they say, but I know I am in the zone.
    Really? I run about 10psi lower than they say.

  179. #379
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    572
    Quote Originally Posted by NordieBoy View Post
    Really? I run about 10psi lower than they say.
    There are a lot of factors like tubed v. tubeless, tire size and rider weight but I definitely couldn't drop another 10psi from what they recommend. They said 29 or 30 for my 26". I definitely couldn't go down to 19 or 20 on those wheels. Things get squirrelly the closer I get to 25. Similarly, I can't see running my 29er as low as 16 or 17. Though this is a new ride for me and I have been dropping the pressure each day I have been out. 24 is the lowest I have gone on rocky terrain with some good climbing and the extra grip was perfect. But the front end was getting a little unstable in tighter turns on downhill and hardpack. Still figuring it out.

  180. #380
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    Quote Originally Posted by wahday View Post
    There are a lot of factors like tubed v. tubeless, tire size and rider weight but I definitely couldn't drop another 10psi from what they recommend. They said 29 or 30 for my 26". I definitely couldn't go down to 19 or 20 on those wheels. Things get squirrelly the closer I get to 25. Similarly, I can't see running my 29er as low as 16 or 17. Though this is a new ride for me and I have been dropping the pressure each day I have been out. 24 is the lowest I have gone on rocky terrain with some good climbing and the extra grip was perfect. But the front end was getting a little unstable in tighter turns on downhill and hardpack. Still figuring it out.
    Day to day on my fully, I run 24f/29r and for racing on the hard tail, 21f/24r.
    Both with tubes and 180lb rider.

    When I was running tubeless on the fully, most tyres were best for me about 25psi on the rear, except for a Hutchy Python which had a sweet spot around 29psi.

    Lots of figuring out involved...

  181. #381
    mtbr member
    Reputation:
    Join Date
    Dec 2013
    Posts
    1,095
    The advice "Lower your pressure until you experience pinch flats" makes sense if you're running tubes. But what if you're tubeless? "Lower your pressure until you destroy a rim" is not a very palatable answer.

    How does one balance the desires to 1) experiment with pressures, and 2) not destroy their expensive rims?

    I'm guessing gently bottoming out isn't a problem, so the key is to learn what that feels like and avoid it?

  182. #382
    mtbr member
    Reputation: J.B. Weld's Avatar
    Join Date
    Aug 2012
    Posts
    14,143
    Quote Originally Posted by matto6 View Post
    I'm guessing gently bottoming out isn't a problem, so the key is to learn what that feels like and avoid it?
    That's what I do. If I feel a rim strike or 2 on a ride I know I'm running a couple psi low. Also if it starts feeling squirrly in corners. I haven't damaged any rims due to this, it seems pretty obvious if it's dangerously low.

  183. #383
    mtbr member
    Reputation:
    Join Date
    Feb 2013
    Posts
    180

    Re: Tire pressure for all around XC riding?

    Quote Originally Posted by matto6 View Post
    The advice "Lower your pressure until you experience pinch flats" makes sense if you're running tubes.
    Not sure this makes any sense at all! The last thing I would want when out on the trail would be a flat to fix and risking a ruined tube. Not good advice in my book.

    I run tubeless between 26-30 psi as the trails I ride are generally more rooty and fast rolling. When I was tubed it would be in the 35-40 psi range.

    Sent from my Nexus 4 using Tapatalk

  184. #384
    mtbr member
    Reputation: J.B. Weld's Avatar
    Join Date
    Aug 2012
    Posts
    14,143
    Quote Originally Posted by coxinio View Post
    I run tubeless between 26-30 psi as the trails I ride are generally more rooty and fast rolling. When I was tubed it would be in the 35-40 psi range.

    I used to do that back in the 90's, tires were a lot skinnier and good info was harder to come by then though. 25 psi for me with 2.2/2.3's, and I have yet to pinch flat due to this.

  185. #385
    mtbr member
    Reputation:
    Join Date
    Feb 2013
    Posts
    180
    Quote Originally Posted by J.B. Weld View Post
    I used to do that back in the 90's, tires were a lot skinnier and good info was harder to come by then though. 25 psi for me with 2.2/2.3's, and I have yet to pinch flat due to this.
    Good advice and old habits die hard, will try lowering pressure next time I'm running a tube.

  186. #386
    mtbr member
    Reputation: jeremyreed's Avatar
    Join Date
    Jan 2014
    Posts
    330
    Im 220 on 2.0 tires on my cannondale.whats a good pressure I could run on the trails?

    Jeremy Reed

  187. #387
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236

    Tire pressure for all around XC riding?

    Quote Originally Posted by jeremyreed View Post
    Im 220 on 2.0 tires on my cannondale.whats a good pressure I could run on the trails?

    Jeremy Reed
    Read this thread. It tells you how to find what works for you.
    mtbtires.com
    The trouble with common sense is it is no longer common

  188. #388
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    Quote Originally Posted by shiggy View Post
    Read this thread. It tells you how to find what works for you.
    Good thread, thanks

  189. #389
    mtbr member
    Reputation: jeremyreed's Avatar
    Join Date
    Jan 2014
    Posts
    330
    I have mine both at 40 now..rated low is 33psi and high is 55....

    Jeremy Reed

  190. #390
    mtbr member
    Reputation:
    Join Date
    Apr 2008
    Posts
    80
    Conti XKing 2.2, 175lb, 25f/28r. (tubes)

  191. #391
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    At the moment, on the hard tail, Conti X-King 2.4's (55mm width, with tubes), 17psi front, 21psi rear.
    16f/20r and I got a couple of rear rim strikes when seated.

    87kg, fast(ish) cruise speed, rocks and roots only a couple of cm high.

    On the fully, Hutchy 2.1's, Toro front and Bulldog rear. Both tubed. 20f/24r.
    Last edited by NordieBoy; 09-09-2014 at 02:35 PM.

  192. #392
    mtbr member
    Reputation: cnitram's Avatar
    Join Date
    May 2012
    Posts
    127

    Tire pressure for all around XC riding?

    20 front / 25 rear...tubeless

  193. #393
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619
    Quote Originally Posted by cnitram View Post
    20 front / 25 rear...tubeless
    What tyres/widths?

  194. #394
    mtbr member
    Reputation:
    Join Date
    Feb 2014
    Posts
    305
    I run Hans Damf 2.35 Front and NN 2.25 Rear. I weigh 155 with all my gear. I used to run 25 front and 28 rear. After my rear losing traction every now and then, and my current rides getting hotter as the ride progresses, I've lowered my pressures to 21/23 respectively. The air inside the tires expands with the heat and the tires do feel harder after the ride. I find that this is perfect for my riding style, terrain and ability - moderately aggressive/dry, loose gravel/intermediate skills.

  195. #395
    K&K
    Reputation: ki5ka's Avatar
    Join Date
    Dec 2006
    Posts
    935
    I think for some people, a flat, a ruined tube, or a dinged rim is a big deal, for others, its just part of the experience; a good explanation why there are such widely ranging ideas of what is the "right" pressure.

  196. #396
    mtbr member
    Reputation: SDMTB'er's Avatar
    Join Date
    Feb 2014
    Posts
    1,173

    Tire pressure for all around XC riding?

    220 geared up. Start rides with 25 front, 30 back, but may reduce pressure if conditions dictate (my non scientific system is to do a five count while pressing in the valve which equals roughly 5 psi). Happened yesterday - bone dry here in SD and a lot or the trail was loose rocks and I was bouncing / skipping around and under steering. Using hookless carbon rims, Hans Dampf 2.3 up front, Racing Ralph 2.2 in back. I have to say I much preferred the ride of the lower pressure and even though I was at approx 20 front, 25 back. Unless you are flying off 2 plus foot jumps or are slamming your bike into everything, the lower pressure (tubeless) should be good to go as far as flats.

  197. #397
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    4,971
    For tubes, run as low as you can without pinch flatting. That'll be your limiting factor. For tubeless, go as low as you can without having the tire roll under while cornering, or without feeling like it's wandering. It'll change on different width rims. I can go lower on 21 mm rims than I can on 17 mm rims with the same exact tire.

  198. #398
    mtbr member
    Reputation:
    Join Date
    Sep 2014
    Posts
    7
    Guess i have been on road/TT bikes too long... I still have a "mental" issue going below 30psi on my tubeless setup.. All I can think about is rolling resistance.

  199. #399
    mtbr member
    Reputation:
    Join Date
    Jun 2014
    Posts
    816
    Yep, you have. Different ballgame.

  200. #400
    Armature speller
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,619

    Re: Tire pressure for all around XC riding?

    Quote Originally Posted by XTERRAGreg View Post
    Guess i have been on road/TT bikes too long... I still have a "mental" issue going below 30psi on my tubeless setup.. All I can think about is rolling resistance.
    I have a 30psi mental barrier too, but mine is the opposite. If I have to, I'll put 29psi in, but I can't put 30.

Page 2 of 3 FirstFirst 123 LastLast

Members who have read this thread: 143

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.