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Tire pressure for all around XC riding?

458K views 583 replies 276 participants last post by  Travolta 
#1 ·
I was curious to know what tire pressure is the best for all around xc use?
I had IRC Mythos on my K2 and ran them very high because someone told me that I would get pinch flats left and right if I didn't.
I now have Kenda Nevegals on my Cannondale Rush and was curious where people tend to have their pressure set. I normally ride pretty rocky/root filled technical terrain, with a little mud thrown in once in a while and some nice long downhills.
Any suggestions would be great. Thanks
 
#11 · (Edited)
i am always somewhat confused about what pressures to run for trail riding, but what seems to "feel" best to me (i weight about 170lbs with gear) is 28 psi front, and 36 psi rear on maxxis high roller 2.35 single ply's, give or take a very few psi. any more on the front and it feels sketchy, less and i feel the rim getting tagged on bigger rocks. on the rear, less than 36 and it feels like the bike won't roll fast enough (and rim gets tagged), more and i can feel the back skipping over too much stuff, braking is bad, and too much boot-boot. i tend to try to run as much pressure as i can get away with though, because i have more fun riding when the bike rolls faster - this is for general trail riding. but for bike parks i run 2.5 maxxis 2-ply dh tires with 27 psi front, and 35 rear, exactly. for dirt jumps i run 40 psi front, and 50 psi rear for railing berms at high g's - although this can vary more since you don't have to deal with terrain on flow trails.

why more in back than front? because i DO look at my tires while i ride! one of the things i do when testing a different tire pressure is do a "tire sag" check - i sit on the bike and look at the tire to see how much it bulges at a certain psi. i can't explain here how to judge this, but keep in mind that a tire works best on a certain size of contact patch that will vary with psi, tread design, rider weight, casing design, tire size, rider weight distribution, riding style, dynamic forces while riding, and other factors. as part of my riding style, i try to keep the front end light as often as i can by keeping my weight on the pedals (not on my hands), and when riding faster and more aggressive (which i do as often as possible) the weight distribution shifts more rearward. add to this that the weight distribution on my bike is already 40/60 front-to-rear. so, the weight distribution calls for more pressure in the rear and less in the front to keep things balanced-out.
 
#531 ·
Weigh 225 6'3"
Tires XR4 29X2.3 Team issue front and rear
Roval Traverse SL 30mm internal
XC and fairly aggressive trail riding
21 psi front, 26 rear

Sent from my iPhone using Tapatalk
Thanks for this.

I'm 220 and just installed a pair of 29 x 2.4 XR4's on my Trance with 30 mm ID rims.

I tried the suggested 30R/28F yesterday on the stock Minions and it felt way too hard.

I'm lost with tire pressure as I've been on 29+ the past few summers.
 
#18 ·
Spawne32 said:
22psi? isnt that kinda low? whats your tire look like while riding.
It's fine. Remember, that pressure is in a wider 2.3-2.4 tire. Once you feel how your tires can conform to rocks and roots rather than bouncing off of them, you will appreciate lower pressures. To be honest, I've never had issues with pinch flatting. I think part of it is due to the the mainly rounded rocks we have around here (thanks glaciers), and part is due to the fact that I started mtn biking on rigid bikes and even though I run suspension now (front and full), I still unweight the bike as I go over and through stuff.

I've played with all kinds of pressures over the years. In the early 90s I started running between 30 and 35 psi because I was new to MTB and the people that knew what they were talking about recommended lower pressures (that seemed low to me at the time). Later on I got sucked into the "higher pressure is faster" thinking and started running 40 - 45. I also remember that some tires during the mid 90s started coming with separate pressure recommendations if you were riding suspension versus rigid (min pressure on suspension was like 5 or 10 psi higher), so since I was running front suspension then (if you can call a 63mm Judy suspension), I went with the recommendations.

Eventually (years later) I got sick of bouncing and glancing sideways off of every rock and root on the trail and started lowering my pressures again. Then in more recent years I discovered wider 2.3 - 2.4 XC tires (I had been running 1.95s to 2.1s up to that point) and even lower pressures, and a whole new world opened up to me. I was more than happy to trade some speed for better traction and control, but then I started reading in these forums that I probably wasn't sacrificing speed by running lower pressures anyway. So all is good:thumbsup: . Now I just feel like an idiot for running 40-45psi for all those years.
 
#160 ·
My pinch-flat-free streak is over.

To be honest, I've never had issues with pinch flatting. I think part of it is due to the the mainly rounded rocks we have around here (thanks glaciers), and part is due to the fact that I started mtn biking on rigid bikes and even though I run suspension now (front and full), I still unweight the bike as I go over and through stuff.
Well, I can't say this anymore. After 2 decades of riding without ever getting a pinch flat and having run pretty low psi for at least the last 5 or so years, it finally happened. I was heading out for a quick trail ride on my rigid SS this afternoon, and though I normally put 24-25 in a rear 2.1 tire, my gauge read 23.5 and I thought "that's fine". Well, immediately after hitting a crude rock bridge (basically a line of larger rocks across a shallow creak), I heard the air whoosh out and knew my luck had finally run out. To make things worse, since this was just intended to be a quick ride, I didn't bring a spare inner tube as I normally do, and, of course, my unopened tube of rubber cement in my patch kit was empty when I perfed the top (I've had that happen before with old patch kits). So I got to walk.
 
#19 ·
mr.niles said:
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?
The reason that most mtb tires are faster on dirt at lower pressures is really rather simple. A tire at lower pressure will flow or comform to bumps, smaller rocks, or square edged obsticals. A tire at higher psi doesn't do this, rather it has to make contact with the obstical and climb over it. This creates a bump that you can feel and in many cases the tire looses contact with the trail surface. It takes more time for the tire to bump over the obstical than it does to have it flow over it. The effects of higher pressure are, slower speed, less traction, less control. The lower pressure tire will have the opposite effect. But as the others have noted there is a limit to how low you can go. Rider weight, riding style, tire volume, tire construction, terrain, etc. all work to determine the "sweet spot" for a given tire. The sweet spot is that golden compormise pressure where the tire provides the best traction and performance without feeling squirmy or being so soft that you ding rims, etc. And I've never had two different tires that had the same sweet spot, and it takes a bit of work to find it. But if you go at it right it can be allot of fun.

As for where to start, Surly29 had it right. Start with the lowest recommended pressure for the tire and ride it. If you don't get a pinch and the tire doesn't feel squirmy on the first run, drop pressure on the next run by 2 or 3 psi. If you do get a pinch or tire squirm up it by 2 or 3. So drag your pump and your bike to the trail and have fun. :thumbsup: Oh and just as a side note, make sure you take a couple of spare tubes and have an inflation device along on the bike. Cause you will most likely pinch flat at least once. :D

Good Dirt
 
#238 ·
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.
 
#501 ·
This thread has lasted 10 years and in case it goes another 10 may I suggest to include the following information if you are discussing pressures that work well for you. Many have - thank you, the information is helpful. Many have not - and I can't help thinking what is the point?

your weight
tire model and specs (size, tread width)
rim width if you know it
type of riding and terrain

Thanks. That would really help. Of course I'm referring to tubeless. If you're running with tubes in 2019 I'm sorry but nobody cares.
 
#547 ·
As a rider weighing in the upper 180's to 190's and eventually over the years in the clydesdale category, I ended up running the rear around 25 psi (hardtail) and the front tire at 22-23psi, depending on terrain. Rockier areas where I ride, I usually bump up the rear to around 28-29 psi just for piece of mind. Seems to work well for my riding style, bike and areas I ride. Haven't blown a tire or bent a rim yet due to low tire psi.
 
#549 ·
This is where I'm at. Upper 180's to lower 190's. Rear psi has been in the 24-25 psi range with the front around 22 psi depending on the tire. When I was a clyde rear pressures were up around 28-29.

I try to start at a reasonable psi then adjust up or down on the trail as the ride progresses. With the rear, I'd ride it lower and lower until i started to get rim strikes. Then I'd add 2-3 psi.
 
#570 ·
Silca --yes, the company that make heirloom-quality bicycle pumps --has done some research on this topic, albeit primarily focused on road and gravel riding. The result is this online calculator. For mountain bikes, just pick "single track" and Cat 4 Gravel or Cobbles. There is ample evidence to support the notion that most folks are running waaaaay too much pressure on the road and gravel. Probably, XC racer-types too. I do which they would factor in the "insert" variable as well, but I listened to a podcast from them the indicated inserts don't impact rolling resistance that much. The calculator does aim to prevent you from pinch-flatting so I would bet the do eventually add "insert type" as a factor.

I find it pretty accurate, if you take the time to enter the correct information ...especially total system weight.
 
#3 ·
As low as possible. I'd start at the lowest recommended pressure (as printed on the tire) and see if you get a pinch flat (small holes on both sides of tube where it contacts the rim). If so, put in a few more psi and run that. If you don't get a pinch flat, run a few psi lower until you do pinch flat.

Tire pressure is an individual thing. You may also play with the pressure to see how it effects handling, traction, and rolling-resistence.
 
#5 ·
Lugi said:
I was curious to know what tire pressure is the best for all around xc use?
I had IRC Mythos on my K2 and ran them very high because someone told me that I would get pinch flats left and right if I didn't.
I now have Kenda Nevegals on my Cannondale Rush and was curious where people tend to have their pressure set. I normally ride pretty rocky/root filled technical terrain, with a little mud thrown in once in a while and some nice long downhills.
Any suggestions would be great. Thanks
You have to experiment. Keep dropping the pressure until you start getting pinch flats or the tires feel squirmy in the corners, then add 2-3 psi. This will be where most tires will preform the best, though a few models may have a sweet spot that is a little higher depending on riding style and terrain.
 
#6 ·
I'm a big fan of lower pressures. I generally run about 22-23 on my 2.3-2.4 tires, 24-25 on 2.1's. I weigh 160 and ride rocky and rooty trails, but the rocks around here tend to not have sharp edges. I will add a couple psi if I expect to be riding somewhere with sharper rocks. My trails also tend to be a lot of slow technical riding, so the low pressure really pays off. If I expect to ride somewhere with higher speed turns, I will up the pressure a little to avoid that squirmy feeling Shiggy mentioned (it can be real unnerving). I am running tubes (not tubeless).

Also be aware that I have yet to find 2 tire pressure gauges that give the same reading, so my psi listings are relative to my main tire gauge.
 
#7 ·
trailville said:
I'm a big fan of lower pressures. I generally run about 22-23 on my 2.3-2.4 tires, 24-25 on 2.1's. I weigh 160 and ride rocky and rooty trails, but the rocks around here tend to not have sharp edges. I will add a couple psi if I expect to be riding somewhere with sharper rocks. My trails also tend to be a lot of slow technical riding, so the low pressure really pays off. If I expect to ride somewhere with higher speed turns, I will up the pressure a little to avoid that squirmy feeling Shiggy mentioned (it can be real unnerving). I am running tubes (not tubeless).

Also be aware that I have yet to find 2 tire pressure gauges that give the same reading, so my psi listings are relative to my main tire gauge.
22psi? isnt that kinda low? whats your tire look like while riding.
 
#9 ·
shiggy said:
Evidently, not for him. I rarely have more than 30psi (usually less) in any of my tires and I outweigh trailville by at least 20 pounds.

I do not look at my tires while riding.
i mean like when weight is on it, i would figure 20psi on that size tire would be almost flat
 
#13 ·
mr.niles said:
i am always somewhat confused about what pressures to run for trail riding, but what seems to "feel" best to me (i weight about 170lbs with gear) is 28 psi front, and 36 psi rear on maxxis high roller 2.35 single ply's, give or take a very few psi. any more on the front and it feels sketchy, less and i feel the rim getting tagged on bigger rocks. on the rear, less than 36 and it feels like the bike won't roll fast enough (and rim gets tagged), more and i can feel the back skipping over too much stuff, braking is bad, and too much boot-boot. i tend to try to run as much pressure as i can get away with though, because i have more fun riding when the bike rolls faster - this is for general trail riding. but for bike parks i run 2.5 maxxis 2-ply dh tires with 27 psi front, and 35 rear, exactly. for dirt jumps i run 40 psi front, and 50 psi rear for railing berms at high g's.
Some time you should actually put a clock (or GPS) on your runs and see how different pressures affect your speeds.

I have done this with a Garmin Edge GPS when testing tires. The runs that felt the fastest were many times the slowest. They where exciting and it seemed I was going into the corners at a higher speed but in reality the tires where just bouncing and sliding more and harder to control. Slower into the turn and slower yet coming out of them. Heck, the higher pressure runs where even slower on the climbs.

That is not to say the faster, low pressure runs were more fun. There was a lot less drama in covering the lap. Definitely not as thrilling a ride.
 
#15 ·
well im about 165 pounds and 40 psi in the rear is usually where i feel comfortable, adding a bit more flex to the front tire might make it a little easier on my arms but i dont know how much more difficult it would be to accel the bike forward with lower tire pressure. I might play around with it a little more now that i got my CST copperheads mounted today.
 
#16 ·
shiggy said:
Some time you should actually put a clock (or GPS) on your runs and see how different pressures affect your speeds.

I have done this with a Garmin Edge GPS when testing tires. The runs that felt the fastest were many times the slowest. They where exciting and it seemed I was going into the corners at a higher speed but in reality the tires where just bouncing and sliding more and harder to control. Slower into the turn and slower yet coming out of them. Heck, the higher pressure runs where even slower on the climbs.

That is not to say the faster, low pressure runs were more fun. There was a lot less drama in covering the lap. Definitely not as thrilling a ride.
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?
 
#306 ·
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.
 
#17 ·
Over 190 with water and gear, 30 in the front and 32 in the rear with small 2.4's. These tires are definitively faster at 30-32 than they are at 40 or more whether I am on the road or the trail. I wouldn't have believed it if I had been told beforehand. I tried 28 in the front and 30 in the rear but felt the rim hit on both ends during that ride.
 
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