# Tire Pressure for XC



## cyberdivachick (Jan 30, 2007)

Hey Ladies!
What tire pressure is everyone using for their XC and DH rides? I was really tired last night, so I cranked up the pressure in both tires to 50 pounds thinking it would help a lot climbing, and the ride just felt really bumpy, squirmy, and I was sliding through everything. Normally I use about 40 pounds. 
On my DH bike I have been using 25 pounds both in front and back as well.

Thanks for your help.


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## alaskarider (Aug 31, 2004)

It really depends on the types of trails you ride, your bike setup, your tires (tubeless or not, width), and your weight. I like to ride about 35psi on my tubeless full suspension, but I'm also pretty light (110 lbs). My husband (about 155 lbs) likes to ride around 40 psi on both his bikes. 50 psi sounds pretty high based on what others I know usually ride.


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## chuky (Apr 3, 2005)

A lot of people over inflate, but It depends upon your set-up. For xc I almost never run anything higher than 25. My 26" wheels are all tubeless, I weigh 125. I used to get away with 20 on my singlespeed with huge tires, made climbing really nice and grippy. I have a 29er with tubes, and I still keep it around 25, haven't flatted yet, and I do ride almost every day.

(after these statements, I will probably have epic flats, knock on wood).

You have to test your tire and inflation combos in your specific conditions. What works for some places won't work for others.


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## Asthmaniac (Apr 10, 2008)

I run around 28 for XC, depending on conditions. If I know I have a long fireroad climb to start I'll put a little more in, then let some out before the singletrack down. I think my DH tires run around 25. That's on 26" wheels with tubes, full susp, and I'm 130.


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## Berkeley Mike (Jan 13, 2004)

*My XC riders*

run modest surfaces and supply their own power as (opposed to DH.) As such 40 psi+/- 3 pounds is common. My Champion runs 50. My other top Varsity rider runs 47. All tubeless. I argue with neither one as results speak for themselves. Learning to handle bikes at this rate is a skill in itself.

By the way John took 2nd in 18-under Jr. Expert at Mt. Snow, Vermont, last week. Roots and rocks were more prevalent than he was used to and found his tires just fine. He felt that dual suspension would have been a nice advantage in some places, relying upon that to keep contact and not some low psi.


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## connie (Mar 16, 2004)

Incidentally, Gene just sent this out in his email newsletter this morning:

Interesting report showing that higher tire pressure does not equal lower rolling resistance off road:

http://www.bicicletta.co.za/Downloadable docs/Rolling Resistance Eng illustrated.pdf


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## Mtnchick (May 28, 2008)

Wow! I guess I've never thought about running my tires at as low as 20-25 psi. I just have listened to my husband who keeps his at about 40-45 and weighs about 220 lbs. Since I am 125 lbs., maybe I should try less pressure and see how it goes.

Thanks for all the great info!!


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## connie (Mar 16, 2004)

Mtnchick said:


> Wow! I guess I've never thought about running my tires at as low as 20-25 psi. I just have listened to my husband who keeps his at about 40-45 and weighs about 220 lbs. Since I am 125 lbs., maybe I should try less pressure and see how it goes.
> 
> Thanks for all the great info!!


It does depend on a lot of factors - whether your running tubeless or not, how beefy your tires/sidewalls are, the amount of pointy rocks and such on the trail to pinchflat on, etc.

But yeah - I usually run 18-25 on my DH bike and 25-32 on my singlespeed. And I run tubeless on everything.


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## Mtnchick (May 28, 2008)

My new Yeti 575 is supposed to be in tomorrow, so hopefully I will get to play with the tire pressure this weekend.

I'll start with the stock Maxxis tires that come with it, and see what I think.


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## chuky (Apr 3, 2005)

Asthmaniac, changing your tire pressure during an XC ride is kind of OTT IMO, and the logic of this escapes me, as you will never make up the time you waste screwing with your tires. However, wouldn't you generally do the reverse? Lower pressure widens the surface area of your tire on the ground, giving you more traction/power for the climbs, higher pressure on the descents would help protect against speed related flats IF that was your concern, though downhill handling also tends to benefit from lower pressures.

Riding a singlespeed on a few climbs at varying pressures will illustrate this very clearly for anyone who is curious.

Oh, and that article Connie posted is quite good and interesting.


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## Berkeley Mike (Jan 13, 2004)

*Interesting article*

I read something like it for road bikes. It still means one has to be thoughtful about pressures and there is no one answer.

This is going to be a tough sell.

The other day my wife did a ride we have done before and she said it felt hard. The next day I found her pressures at 20-22. I pumped them back up to 40. After her ride she said it felt a lot easier.(some pave, fire road, some loose stuff.) she knows very little about all of this but knows that it was easier.

I had my top riders test out some Kenda product by doing repeats on a piece of ground over in China camp. 3/4 mile, 4% grade, in and out of ravines in changing surfaces. 4 kids, a coach and a pump. Tubes. A fair bit of speed. Anything below 34 was mushy in the turns and above 45 it was too bouncy. These guys weighed 150-172. 22-25 lb HT's.

What this says is that there is a body of experiential info out there that just doesn't agree with the "science" in the article. Definitions of surface, tube/tubeless, faith in the measuring device are all factors. Stuff like this is not the last word for me any more than the latest dietary information.


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## badjenny (Mar 13, 2006)

Like most of these ladies I also run very low psi. I am 105lbs and run below 30 psi, usually 28ish. I ride ss and geared hard tails. The only time I run it higher is if I know it is going to be smooth, flatish trails. I run that psi with both tubeless and tubes. 

I cringe at even saying the next statement... I have never flatted during a race (furiously knocking on wood). If memory serves correctly I have only flatted twice on normal rides and one was a side wall blowout (torn on a rock). 

If you decide to run it that low get used to everyone you encounter saying you need more air in your tires... and the shop guys blowing yout tires up to like 50 psi every time. Argghhh!!! I don't like riding on ice skates.


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## Berkeley Mike (Jan 13, 2004)

*Badjenny*

By sharing your flat experiences you are treading dangerously with the Flat Demons. You are taking one for the team. I am knocking on wood for you, too!


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## jewels (Mar 17, 2004)

I like to keep my tires at 20-25psi (tubes and 2.3 nevegals). I'm most comfortable at 20psi though. I go down to 15psi when it's wet and snotty. But the mud gets pretty slick, making tough sections even harder. I figure I can use all the traction i can get. I'm trying to learn to run harder tires, but when I feel that I'm losing traction at all because of it, I have no problem letting a bunch out.


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## verslowrdr (Mar 22, 2004)

It's interesting to see the responses on this thread. I weigh a good 150-ish, usually carry at least 5 more pounds of tools etc. on my back, and run good ol' Hutch Pythons (light XC tire that runs pretty well in our normally dry conditions). Trails I'm on often include random sticks, rocks, stump remains, and little willow nubs. 

If I ran pressures as low as some have mentioned here, I honestly believe I'd be dinging rims. Obviously I'm a big gal on fairly thin walled tires so YMMV.


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## connie (Mar 16, 2004)

verslowrdr said:


> It's interesting to see the responses on this thread. I weigh a good 150-ish, usually carry at least 5 more pounds of tools etc. on my back, and run good ol' Hutch Pythons (light XC tire that runs pretty well in our normally dry conditions). Trails I'm on often include random sticks, rocks, stump remains, and little willow nubs.
> 
> If I ran pressures as low as some have mentioned here, I honestly believe I'd be dinging rims. Obviously I'm a big gal on fairly thin walled tires so YMMV.


It's definintely not just for skinny people. I'm bigger than you and I run low pressure. And my husband weighs probably 220lbs and he runs low pressure too. Going tubeless is key. And if you're on really rough terrain, something with a decent sidewall helps too.


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## chuky (Apr 3, 2005)

I carry a ridiculous Camelbak - I am the person who always has a first aid kit, a jacket, extra food and all the water that fits. If I add armour, etc, 125 is certainly a ways away.

As far as terrain goes, Utah isn't exactly devoid of rocks:



I think that the pressure you use with your particular tire/rim combo has to be tested if you want optimal results. If you don't test it, you will never know if it could be better.

C


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## badjenny (Mar 13, 2006)

Berkeley Mike said:


> By sharing your flat experiences you are treading dangerously with the Flat Demons. You are taking one for the team. I am knocking on wood for you, too!


I am counting on good trail side kharma to keep me in the good graces of the flat demons.


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## Asthmaniac (Apr 10, 2008)

chuky said:


> Asthmaniac, changing your tire pressure during an XC ride is kind of OTT IMO, and the logic of this escapes me, as you will never make up the time you waste screwing with your tires. However, wouldn't you generally do the reverse? Lower pressure widens the surface area of your tire on the ground, giving you more traction/power for the climbs, higher pressure on the descents would help protect against speed related flats IF that was your concern, though downhill handling also tends to benefit from lower pressures.


It's hardly wasting time. I ride with my bike club and we all do it on fireroad climbs. I just put a few extra pumps in the tires before I leave my house. After the ride up we're all busy eating lunch and admiring the great mountain views of the PNW, so there's plenty of time to let a bit of air out. This isn't a race, it's a club ride. We socialize, that's why I like it 

If I had 40lbs. of pressure for the ride down a rooty, and oftentimes snotty, PNW trail, I'd be bounced right off my bike. The lower pressure helps give traction over our type of terrain. From the article: "A tyre with less inflation can adapt to unevenness more easily."

As has been said, depends on your situation.


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## cyberdivachick (Jan 30, 2007)

wow, great stuff! My XC tires are both 2.4 and I weigh about 145 pounds. I am going to try the pressure at 35-38 now instead of 50 pounds. Hopefully I won't be so squirmy. Thanks!


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## connie (Mar 16, 2004)

chuky said:


> I think that the pressure you use with your particular tire/rim combo has to be tested if you want optimal results. If you don't test it, you will never know if it could be better.
> 
> C


Ditto. Even if we're talking the same person on the same trail - different tires/rims often require different pressures to feel right. So play around with it for sure. And go tubeless if you haven't - you don't need special rims/tires - just a rim strip and Stans. And then you can really play with low pressures and not worry about pinch flats.

And nice pic! That's pretty much my line through there too. So fun!!  We do have plenty of rocks to test tires on, that's for sure!


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## Fabulous (Jan 20, 2008)

*guess I run really low*

I run at around 10-15 psi on the trail, and 35 on the pavement on the way to/from the trailhead. I'm 110 on a 27 lb FSR with 5-10 lbs of gear/water. my tires and rims are tubeless ready, but I still run them with tubes. As for trail conditions, some days it seems like the trails around here are more rocks and roots than dirt.

I didn't realize how low I was running the pressure in my tires until I pumped my tires with someone's gauged pump the other day. I usually set them by feel and sight. If they're looking like they are bulging a lot while I'm sitting on the bike I put some more air in, if they are spinning out on the loose stuff I let some out.


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## Brodiegrrl (Jan 12, 2004)

Depends on the conditions. 

I try to run my tires as hard as conditions allow. 

In the Whistler Bike park I like 50lbs so I don't flat. If its wet I will reduce the pressure. 

On my XC bike with 2.1 tires, I find running anything less then 40 will be pinch flat city. I try to run them at 50. But again conditions. 

If its wet out, go with as low as you can. If its dry as hard as you can. 

I have a ti hard tail with 2.25 el gatos that I can run at 20lbs psi! Who needs suspension! Which I do when its wet, higher when its dry. This pressure SUCKS on the road.


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## Impy (Jan 6, 2004)

I run about 20-25 pounds PSI. The higher range if I'm riding to the trailhead (and thus more pavement). I do run tubeless. The lower pessures help a lot with climbing the loose crumbly steep stuff here in socal.


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## verslowrdr (Mar 22, 2004)

I'm running regular ol' tubes, and believe it or not I have actually played with lower pressures by virtue of having some slow leaks that I was too lazy to fix and too lazy to pump up every time I rode. From what little I can recall I keep mine at over 40 psi or the ride starts getting pretty slimy on corners in the front and I start getting worrisome (not to mention draggy) bulge in the back.

I have to believe that the relatively thin walled pythons would factor in somehow, as well as the generally hard pack/dry trail conditions we have here. Even at fairly high pressure the pythons hook up amazingly well... well, really well until I run into a patch of the d**ned sand as mentioned in the other post, lol.....


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## Sambolina (May 15, 2007)

This may help you based on your weight:  131-150lb
rider 27-31 F, 30-34 R. This is based on tubed tires. If you run tubeless u can run lower tire pressure.


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## [email protected] (Aug 24, 2005)

*Tubeless*

XC 25-32# DH 18-25# both tubeless with UST tires sizes 2.25-2.8.


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## janedoh (Mar 26, 2008)

cyberdivachick said:


> Hey Ladies!
> What tire pressure is everyone using for their XC and DH rides? I was really tired last night, so I cranked up the pressure in both tires to 50 pounds thinking it would help a lot climbing, and the ride just felt really bumpy, squirmy, and I was sliding through everything. Normally I use about 40 pounds.
> On my DH bike I have been using 25 pounds both in front and back as well.
> 
> Thanks for your help.


yeah, i run 25psi on the dh, and for the xc, i run 30psi. anything more & i hate it, just love the low psi!
have you figured it out yet?


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## jckid (Dec 13, 2006)

105 lb. XC rider here. I prefer to run 25-30lbs. on singletrack. If I have some paved riding to get to the trailhead, I'll start out higher and then deflate when I get to the trail. I've tried running 35-40lbs. on the trails, but it just feels like it beating me to death and the handling is not has good.


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## verslowrdr (Mar 22, 2004)

*Funny moment at LBS Thurs*

I had a weird deal crop up with a rear tire this week and ended up limping it back to the LBS in the town I'm currently working in. The shop owner Mike is a hilarious character usually spotted these days hoofing around town with his lab Kona trailing behind, drumming up local business sponsors for a frisbee golf course and BMX track. He's probably best known in Washington biking circles for cutting in the local freeride trail RatPac. Suffice to say... dude can ride, and has been doing a lot of it for a long time.

I came back in to pick the bike up and were talking about tires et al when he mentioned my front tire was low. *I* didn't think it was low, it had just a little give to it which is about where I usually like it (have no idea how many pounds that would be exactly but I know it's over 40/45). He was a little surprised and said he rode with his tires 'pretty hard' so he didn't flat or bang up a rim.

I chuckled and started telling him about all the gals in this thread saying they were riding with PSI down in the 20s. Mike's reaction was great: pause... mouth open, eyes wide, turning into a confuzzled frown... then hands in the air and shaking his long blond streaked hair and finally blurting "NO WAY!"

Just picture this guy's reaction and you'll have a perfect mental image:









Anyway, he went on to speculate that yeah, with a tubeless setup and larger tires with stiffer sidewalls, one might be able to get away with twenty-something PSI. But he wouldn't try it with the setup I've got, and he sure wasn't going to try it himself any time soon.

Or perhaps our pressure gauges here in central Washington just decided to go metric in honor of the great BC riding just to the north, and we're all comparing apples and oranges? lol.... don't know, but this will be a question for the couple other local shop owners on my next visit as I'm curious now.


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## hdave (Feb 9, 2005)

so many light weight people (in pounds)...running low PSI.

I am 210 dressed, add pack and water to that. Ran 30 PSI last week and the rear felt pretty mushy. gonna try 35 tomorrow.


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