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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
 
#146 ·
I am runing Botrager XDX, tubeless. Run 18 front 20 rear, and it's ok for grip and bump absorbtion, no rim contact, but if you end up jack knifing the front you will pop the tire of the rim, or loose air presure.
25 front and 30 rear doesn't soak up the bumps as good (you feel more of the terrain) but the tire stays put :)
 
#147 ·
I've posted last year in this thread and was running 2.1 Nevs. Had a ton of flats last year. Running tubes.

This year I switched tires and am running a 1.95 Nev (150g lighter than 2.1) front and my Karma rear (under 400g which is around 280g lighter than the rear Nev 2.1 it replaced).
Pressure for several XC races has been 27 psi front and 29 psi rear with no flats(tubed) (knock on wood!!!)
Traction has been better than I anticipated with a couple of wet races and our local race at Camp Fortune is extremely gnarly, rocky and rough :)
Doing an Ultimate XC race on 19th of June, 100 kms of crazy single track and 10,000 - 12,000 feet of climbing from what I read on this tire combo so will be a good test :)

Cheers,
Paul
 
#149 ·
So a quick report on the UltimateXC 100km race.
Managed to finish in 10 hr and 40 mins with one flat and one slight mechanical.
I was running the 1.95 Nev F @ 27 psi and 2.0 Karma R @ 29 psi.
Where I flatted several other riders flatted. It was a rough fast downhill section.
99 % f the trails were dry or mildly moist. It consisted of soft loamy forest floor to rooty to gravel to Canadian shield solid rock. Were a couple short sections of maybe 50 feet of swamp black mud, bit clayish.
I had super traction except the clay part and a few fast downhills with smallish type gravel.
There were a lot of STEEP sections and the tires had more traction than I had power left haha.
Two gravel climbs of 1 hr each of relentless no stop UP, no plateaus, of 8-25% section of 1600 ft and 1900 ft with 1-2 inch gravel. Was pretty loose stuff but still was gripping well with minimal slippage. Some of the downhill sections after those climbs were insane! ! ! Switchback after switchback hard on the both brakes feathering front brake to not go over bars ! !
In retrospect I am super happy with these tires in any type of dry conditions and non clay type mud. OK on wet roots from other rides.
So for me on my 4" FS GT @ 28ish lbs and me around 135 lbs the 27-29 psi worked really well. I rode just about every type of dry conditions... Sand, tall grass, Loamy forest, rooty forest, big/small gravel, rock, dirt .....
Was a section at finish as we zig zagged downhill through the village on pavement and cobblestones that I was just ripping through and the tires felt super solid with no feeling of the tire wanting to roll on the rim. I felt like I was rolling on the road bike !
Cheers,
Paul
 
#151 ·
Ive kept mine at about 28 front and about 26 back....that seems to work fairly well for me right now. I run tubes and still no issues...but I have tried a gamut of pressures and noticed the higher pressures (at least for me and my trails) tended to slow me down...alot, and backing them off gave me more speed and maneuverability....so my recommendation is to try some variations out for yourself and see what you like
 
#155 ·
Schwalbe RR+ Stan's- Pressure Q for mixed riding

After reading this thread, I switched out my tires for Schwalbe Racing Ralph 2.25 SS rear and 2.1 front, with Stan's on the rims. First time going tubeless.

I'm looking for tire pressure suggestions for overnight adventure racing with these.
We'll hit dirt roads, ATV trails with deep muck-holes, rocky Canadian Shield, unrideable swamps and decent doubletrack. Probably no twisty purpose-built singletrack.

I'm a light guy at 150lbs but my bike's got a lot of rear weight bias, and I'm carrying a lot of gear, much on a rear rack (Long story). I've raced this way for years, with 40PSI in a Hutch Python 2.25 on the rear and a Bonty Revolt-X 2.0 on the front with 30PS!.

I'd appreciate pressure suggestions for the new tubeless setup. I know harder tires would be better for the dirt roads, but I'd lose more time if I can't make it over the nasty bits or if I get flats.

Thanks in advance.
 
#157 ·
I need two more posts so I can start a new thread in "Wheels and Tires", thats where this belongs.

Ever mount your tubeless tires and get a bit of a wobble because the tire is not perfectly aligned on the rim?

How important is it for the tire to roll true?

I had a small wobble once on the rear tire but not bad and it held air just fine. I had a bike shop mount my last pair of tires when I purchsed new tires. One tire wobbled noticeably and hasn't held air very well. I will remount it but I was wondering if there are some tips for getting the tires true to the rims when mounting tubeless tires. BTW- Using Stans sealant, works great otherwise. ALSO, IT'S A SIDE TO SIDE WOBBLE.
The bike is a 2008 stumpy w/ Specialized Captain tires. Rims are Specialized brand and are true.
 
#162 ·
If there is such a thing as an exact science to tire pressure for offroad bike riding then we wouldn't be having these threads all over the net. I read somewhere that the proper pressure should be when the sag is 15%, then what about those tires that use softer compounds? Would the 40% front 60% rear times your body weight formula work in all applications? Is it faster to have a wide tire with low knobs ran at low press rather than the usual narrow high press? Are you really faster overall by having a tire that's fast and slippery rather than a heavier one that grips?

There's no right and wrong. It all depends on the particular trail you're riding, your riding style, and your body weight. I too had spent too much on tires experimenting different types. Sometimes sold them after 1 ride. Unlike in US, all of my tracks involve all kinds of conditions including mud. Now I just ran Nobby Nic Pace Stars 2.1 which has the awesome grip due to soft knobs yet lighter than anything else in the market. I just play with the PSI for the different conditions. Sure soft compounds wouldn't last that long and will cost more $ in the long run but I get both safety, comfort and speed in all conditions.
 
#164 ·
Interesting thread guys ... I have always run high pressures in my tire 'cause I'm a big guy who doesn't like to repair flats. I'm 105kg (231 lbs) and running a 2.5 Weirwolf up front and a 2.4 Motoraptor on the real of my old '95 Avalanche. I had 45 psi in them yesterday and I notice they were a little bouncy so I'll drop 'em to 35 psi and take my friends Mr tire pump and Mr accurate pressure gauge on my next ride.
 
#169 ·
low pressure is better

I will have a look at Stan's thanks

I found 35 psi had an amazing effect on my ride, the bike rolled well stuck to the ground better and my hands didn't get such a beating

So I dropped the pressure to 30 psi and it's even better ...

Thanks for the advice :thumbsup:
 
#184 ·
I overdid it. I had a front tire roll off the rim this weekend after a landing from a tiny jump with the front not completely straight. Just got a digital pressure gauge, and checked how much pressure I had (eyeball the front with fingers, close enough). 10-11PSI in the front, 15 in the rear. Not kidding. No more 15 PSI for me. I will miss the traction, but not miss the tire rolling off :)

The tire pressure gauge is my new riding buddy.
 
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