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  1. #1
    Toby Wong?
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    rear tire pressure - the clyde enigma

    I just don't seem able to run anything less than 40 psi in the rear or I will pinch flat while slamming through rock gardens.

    I'm 225 w/o gear, Mavic 819 UST rims, typically a 2.25 to 2.3 tire on the back

    tires i've tried (trying to stay below the heavy 900g rear tire weight):

    Schwalbe Nobby Nic 2.25
    Nokian NBX 2.3
    Geax Sturdy 2.25 and Barro Marathon 2.3 (actually, no problems with these)
    WTB Motoraptor 2.3

    If the pressure goes below 40 psi, the tire begins to see stress lines along the sidewall when i land a jump or run through rocky terrain.

    What are you lads running for rear tire pressure?

    It's all relative right? I mean, 40 psi shouldn't be some magic number you can't cross, especially given the larger mass of a clyde over it, compared to some 165 lb. dood who can run 32 psi and actually talk about the benefits of lower tire pressure.
    lets not make it a religion, it is recreation

  2. #2
    local trails rider
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    There's no magic numbers: whatever works is good.
    I do not worry about the exact pressure. I only recently got myself a pump with a gauge (pretty inaccurate too). Looks like my eyeball method has put my "2.3" tires (Racing Ralph, Gravity) close to 3 bar / 40 psi.

    edit: the front tyre gets a little less pressure, as there is less weight on it. Enough to make it compress about the same as the rear when I just sit on the bike.
    Last edited by perttime; 07-17-2007 at 11:43 AM.

  3. #3
    Nightriding rules SuperModerator
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    yep.. I am about your weight, Tappoix... I also run the tires around 40 psi... and they feel good... given our weight 40 psi might feel like the 32 psi for a lighter dude..

  4. #4
    On MTBR hiatus :(
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    Sounds about right. I'm around 210 and am pretty particular with my pressures (2 PSI can make a difference!), and I usually ran 40 PSI on my 2.1 26" rear, and 38 PSI on my 2.1 29" rear.

    "Lower tire pressure" is relative to the weight it is supporting.
    speedub.nate
    MTBR Hiatus UFN

  5. #5
    Spring! Spring! Spring!
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    On the square-edge limestone ledgy and sharp rock gardence of Texas ... at 235# w/o gear and riding a 35# bike ...

    - tires smaller than 2.2 on the back needed like 45-50 psi to be safe
    - tires 2.25-2.4 seem to be good around 35 psi
    - tires 2.5+ seem to be good above 25 psi

    BUT, still, infrequent pinch-flats at those pressures from abnormally high-impact situations.

    I do *not* focus on riding lightweight tires, so for some samples of tire selection ...

    2.2 Geax Sedona
    2.2 Kenda Cortez
    2.25 or Geax Sturdy
    2.24 WTB MotoRaptor
    2.4 WTB MotoRaptor
    2.35 Kenda Blue Groove
    2.35 Kenda Nevegal
    2.35 Kenda Small Block 8
    2.4 Kenda Cortez
    2.5 Kenda Nevegal (current favorite)
    2.6 Kenda Kinetics (folding)

    I completely walked away from tires < 2.2 for me back in '01 and have never gone back.

    I do think I need to branch out some more into other tire lines though. Hard to argue with tires that Just Work And Don't Make Me Complain though.

  6. #6
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    Yup, it's all relative...

    to your weight, riding style, terrain, and the tires involved. I'm 230, ride pretty much XC/Trail and do just fine on Nevegal 2.1's at 35psi. Not much for rocks round here. But if I know I'm going somewhere with rock gardens etc. I'll jump to a 2.3 Nev at 35 to 40psi. I've also found that going tubeless isn't the "holy grail" allot of folks think that it is either. With Stans I can drop my pressure by an average of 5psi, depending on the tire, with no problems. But much lower than that I start burping tires and dinging rims. So what's the big deal?!?! I have just as much control and traction with a little more pressure and a tube as I do with a Stans set up. And I think the tubed tires with a bit more pressure roll faster for me.

    So yeah, it's all relative to weight, tires, terrian, and riding style. No magic formula or mirical product, just what works for you and your set up.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  7. #7
    NormalNorm
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    Another Clyde here running around 40psi. Dont give up on tubeless yet. Try some Ust tires. I thought the same thing when I first tried the Stans setup. After the Stans I bought a couple of Ust tires and loved it. Ust is great for us Clydes.

  8. #8
    Klydesdale
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    Quote Originally Posted by norm
    Another Clyde here running around 40psi. Dont give up on tubeless yet. Try some Ust tires. I thought the same thing when I first tried the Stans setup. After the Stans I bought a couple of Ust tires and loved it. Ust is great for us Clydes.

    I've had just as much trouble with pinch-flatting UST tires as I have with tubed tires.

  9. #9
    mtbr member
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    Convert with Stan's NoTubes to Tubless...end the pinchflat nightmare.

  10. #10
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    beware, non-tubless content below

    I was the pinch flat king until I switched to those "thorn proof" tubes which are a lot heavier, but when pumped to 40psi allow me to hammer over everything. That's with 2.1 panracer fire xc's. Have yet to have a flat in a season and a half...

  11. #11
    R.I.P. DogFriend
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    I'm in the 'upper 200's' and need to run over 50psi to avoid pinch flats with a 2.10" tire so your numbers sound about right to me. Now I'm running a 2.5" tire and can run much less pressure (closer to 40psi) with the larger volume. However, there is a weight and rolling resistance penalty to pay for the increased traction it provides. It's worth it me, but YMMV.

  12. #12
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    More to think about.........

    I'm 210 and ride rough XC. In Southern California I got tired of thorn flats and changed over to Stan's notubes. Ran 2.0 specialized Roll-x both front and rear at 22lbs in front and 34 lbs in rear. No problems, no flats, better performance.

    With my move to Vancouver, BC have changed to 2.35 Nevegals dct to take the nasty large rocks and roots. I am now experimenting with pressures. Rode nasty trails near Banif last week at 22/32 and am trying 20/30 just now. Jury is still out on best pressures.

    Added thoughts on Stan's:
    1) first time I set up a tire it was hell.....last week no problem at all. There is a learning curve, just as there was with tubes.
    2) Rode tires with tubes between the switch over....felt hard,and slow like a solid rubber tire. Back to the Stans and The tires just eat the roots and rocks with a soft smooth ride.
    3) Stans works as well on blackberry thorns as it did on desert nasties.

  13. #13
    long standing member
    Reputation: PCinSC's Avatar
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    Quote Originally Posted by Tappoix
    What are you lads running for rear tire pressure?
    I'm pretty much an oddball here, with higher pressure in a heavy, high volume tire. I'm running 40-44psi in a Hutch Octopus UST 2.5" rear on Mavic 823's. This is on my "one bike" which sees techy trail use as well as dedicated DH. For reference, I'm 260lbs plus gear. I have no complaints about its performance.

    It's all relative right? I mean, 40 psi shouldn't be some magic number you can't cross, especially given the larger mass of a clyde over it, compared to some 165 lb. dood who can run 32 psi and actually talk about the benefits of lower tire pressure.
    I would think that a heavier rider would see some those same benefits at a higher pressure. That is until the capabilities of the tire are exceeded. I'd be curious to know how heavy a rider tire companies consider when they are designing/manufacturing tires.

  14. #14
    R.I.P. DogFriend
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    Quote Originally Posted by PCinSC
    I'm pretty much an oddball here, with higher pressure in a heavy, high volume tire. I'm running 40-44psi in a Hutch Octopus UST 2.5" rear on Mavic 823's. This is on my "one bike" which sees techy trail use as well as dedicated DH. For reference, I'm 260lbs plus gear. I have no complaints about its performance.


    I would think that a heavier rider would see some those same benefits at a higher pressure. That is until the capabilities of the tire are exceeded. I'd be curious to know how heavy a rider tire companies consider when they are designing/manufacturing tires.
    Another thing to look at is the max pressures rim manufacturers recommend for the various size tires. As Clydes, we're more likely to exceed recommendations on the rims than we are the tires.

  15. #15
    long standing member
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    Quote Originally Posted by jeffj
    Another thing to look at is the max pressures rim manufacturers recommend for the various size tires. As Clydes, we're more likely to exceed recommendations on the rims than we are the tires.
    Indeed. Mavic recommends a 44psi max with a 2.5" tire on the 823. I pump 'em up to 50-55psi when installing just to seat the bead (and rode with them at 50psi once just to see how they felt), but as a rule keep them between 40 and 44psi.

  16. #16
    mtbr member
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    Have you considered either going tubeless, or possibly running a rear tire that is a tubeless tire and running it tubed? I was using the Specialized S-works 2Bliss tire (tubed) in the rear and was getting as low as 35 in some pretty technical and rocky sections. I weigh 225 without my gear.
    :wq

  17. #17
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    I'm 215 and anything less than a 50# rear-end feels mushy in the turns (45# up front). However I use cheap tube tires tho, Continental Explorers w/ cheap Alexrims.

  18. #18
    Nightriding rules SuperModerator
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    Quote Originally Posted by Big Pwn
    I'm 215 and anything less than a 50# rear-end feels mushy in the turns (45# up front). However I use cheap tube tires tho, Continental Explorers w/ cheap Alexrims.
    that's because of the size... the conti explorers are really small volume tires.. if you moved to something bigger, you would be able to run a bit lower pressure

  19. #19
    mtbr member
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    try thinking about it this way: 165# rider with 32psi in his rear tire and say 60% of his weigh on that tire, contact patch is 3.1square inch. A 225# guy, same weight distribution, same tire would need 43psi to get the same contact patch.

    you don't run the same spring in your fork as a lesser [weight] rider, do you?

  20. #20
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    big tires

    why dont you just use 2.5 tires? it sounds really dumb running 2.1 tires when you weigh 200 lbs. it might be a bit heavier, so what? im 145 lbs with gear, and i run 2.5 tires, still manage to pedal.
    being thicker and larger in volume they eliminate all puncture related issues.

    you dont have to be an aggressive rider to use sturdy components. weighing over 200 lbs is more stressful to the bike than a light rider hucking the crap out of it (i witnessed that myself with complete astonishment).

  21. #21
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    Quote Originally Posted by crisillo
    that's because of the size... the conti explorers are really small volume tires.. if you moved to something bigger, you would be able to run a bit lower pressure
    Great suggestion, thanks! I've only seen the bigger tires on AM bikes doing the same XC stuff as I do, so I had it in my mind that a thinner tire was a bonus for XC handling. I'm sure it would help in all my areas of riding, including the "over-compensation issue" we all cling to lol.

    Seriously tho, how does the handling characteristics differ for 2.1 & 2.5?

  22. #22
    Nightriding rules SuperModerator
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    Quote Originally Posted by Big Pwn
    Great suggestion, thanks! I've only seen the bigger tires on AM bikes doing the same XC stuff as I do, so I had it in my mind that a thinner tire was a bonus for XC handling. I'm sure it would help in all my areas of riding, including the "over-compensation issue" we all cling to lol.

    Seriously tho, how does the handling characteristics differ for 2.1 & 2.5?
    well..depending on the tire of course..usually there is a bit more rolling resistance and weight... but traction is improved as well as comfort, since the higher volume tire at a bit lower pressure can conform to the surface while still giving good support..

  23. #23
    Toby Wong?
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    WHAM!

    Another pinch flat today. CRAP!

    psi was 42 when i left the car. I was totally flowing through the trail and rode *firmly* over a square edged rock. (Hey, what do you want me to do i was feeling it! )

    pssssssssssssssssssssssssssssssst.

    what a pain in the butt.

    i might go back to Geax tires, they have probably been the most dependable UST tires i've tried (i think )
    lets not make it a religion, it is recreation

  24. #24
    El Pollo Diablo
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    fwiw, I can't stand to run anything under 40PSI in the rear...
    and usually run closer to 50.
    freaking hate feeling the rubber get squirmy under me during cornering/riding over stuff.

  25. #25
    mtbr member
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    ... and if we just ...

    strange concept this thread holds........(my best yada impression)

    I top out at #270, ride Heckler on Cloud Nine rear shock, and Super Minute 20mm qrta fork (fwiw)......

    Wheels are Halo Tornado- Tires Hutchinson Spider UST 2.3....Stan'd to hellnback....Stans FR strips over velox tape.....

    I tore a sidewall once, but that is the only problem I have ever had running this set-up. No set-up could live through that, so I chalk it up as a anomaly.... I have never cased the wheels, and I do drop up to 3' to flat semi regularly.... and jump often.... here is the thing that I just don't get- I run 28-29psi in those tires....too my knowledge I have never rolled a tire while cornering- certainly not to the point of burping, and have not had a single trail flat with that above exception in well over two years of using it.....to say I am sold on Stans is an understatement.

    I just can't grasp the problems you guys have stated and relate to them.... at the risk of peeving a few: when you are as heavy as we are it is easy to blame much of our issues on weight.....but on this issue I bet it is something else- rims/tire compatibility for one- I personally believe Clydes should run wider rims (27mm+) to square the tread more and discourage roll off and bites.... the volume is a no brainer- Clydes shouldn't run anything below 2.2 imo... thicker sidewalls meaning Clydes will benefit from UST tires whether they run them tubeless or not unless they are riding on solid smooth surfaces and in a straight line.... My God man, go tubeless-- and if you do or don't use UST rims, use the Stans...... It makes riding a lot more enjoyable as you don't have to worry about it anymore.....

    hmmmm- better traction at lower psi, eliminate snakebites, clog up pesky thorn punctures without even knowing they are there, durability and dependability- vs the exact opposite of what I just said.....cost? how many tubes do you go through in a year? How many rim welds have you broke because of high psi? How often do you have to stop and tear a tire off the rim and repair the tube? frustration alone it is worth it....

    This has been an advertisement.....Mr Stan please make check payable to DrewActual...

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