Mountain Biking - Low PSI= faster offroad?

Some one we rode with the otherday was saying that when you run lower psi you roll faster offroad? Is this true?

Right now I run about 40 psi front and rear.

The lower Psi will give you better traction in some conditions.. saying it will make you go faster, sometimes it all depends on what type of conditions you are riding in.

Faster, nope. More traction, yes.

Yes it will make you faster. I race XC and 40psi is rock hard- I never run that high. I usually run about 30-34psi and sometimes lower.

Higher psi will be faster if the ground is paved or flat fireroad but even then you make up all the time back on singletrack, dh and rougher parts of the course.

Generally, running lower pressure will not make you go faster. Running lower pressure will give you better traction and might make the ride more comfortable. Running higher pressure will reduce your risk of pinch-flats if you are running regular tubed tires. When your friend said that running lower pressure made you roll faster off-road, he might have been trying to say that the lower pressure would give you more traction, therefore letting you hook up with the trail surface better.


-Moab

nope, he was saying running lower psi make your tires "roll" over bumps instead of hiting then and bouncing off. it sounds like it makes sence but wanted to ask on here.

Sounds like bull**** to me. On the street a tire with more PSI will roll faster and the same holds true for the trails as well, unless you're talking about hitting corners faster and having more traction, but in this case we aren't. So no, your friend doesn't know what he's talking about :D

So pump your tires up to 100 psi and go ride the trails.

Mad Dog Jr, try riding at around 34psi and you will see for yourself. Experiment with the psi and you will see what works for you best.

Yep, pressure is all about compromises between rolling fast and having extra traction.

hes not my friend btw, lol. hes an older guy who was riding with us.
He said the same for the road( higher PSI will roll faster) but its the oposite for off road he said. im just afrade to go lower than 35 psi due to pinch flats. do you think 35psi is to low? (im 135 pounds) but i ride aggresive.

As mentioned, the pressure you run should be dictated by the terrain. If you are on very hard packed then higher is better. If you ride over alot of rocks, soft soil, sand and such then a lower pressure will help with traction.

At 135 you could, well depending on what tires you are running, get away with pressure in the low 30's.

If you are running fatties (2.5 or larger) then you could easily run in the 20's. For XC I run 30 front and 35 rear and for DH I run 19 front/22 rear and I tip the scales at 275.

Just go out one day to a local trail, bring a floor pump and tire guage and play around with diff. pressures. Start with say 45 or so, do a quick run then drop it 2 psi. Because you are a light rider you may not notice any chage until you get down to around 34 but give it a shot and see what pressure you like the best.

:beer:

Just go out one day to a local trail, bring a floor pump and tire guage and play around with diff. pressures. Start with say 45 or so, do a quick run then drop it 2 psi. Because you are a light rider you may not notice any chage until you get down to around 34 but give it a shot and see what pressure you like the best.

That's definitely worth the time. I have experiemented with different tire pressure lately during rides and have noticed a big difference in rolling resistance v. traction. Finding your ideal tire pressure based on rider weight and trail conditions can make a huge difference in how your bike rides and how much fun you have.

-Moab

Yep, the right pressure can make or break you. If your pressure is TOO low, the tire will fold on itself. Too high and the tire won't bulge at all and wont conform to the surface. I'm a light rider and the lowest I've run was in the mid 20 PSI range.

sounds like I need to play around a little :D

I used to ride to the max spec of my tires as i used to really like stiff tires, but now i run usually 30 or 35psi.

Originally posted by RacerX
Yes it will make you faster. I race XC and 40psi is rock hard- I never run that high. I usually run about 30-34psi and sometimes lower.

Higher psi will be faster if the ground is paved or flat fireroad but even then you make up all the time back on singletrack, dh and rougher parts of the course.

I agree in a big way, and I've been experimenting with a variety of low psi in the front and rear. Currently, I run about 38psi in the front and 40psi in the rear.

Do you get many pinch flats @ the psi you are running? What do you run in the back, or do you run the same on both tires? Perhaps you are running tubeless???

Please comment. ThanX!! :)

after I bought a new floor pump with an accurate guage I can say I used to use a ~32psi front and rear. With the 2.1 Tioga and 2.3 conti, any less would result in pinchflats. I just put on a WTB Weirwolf on the front in a 2.5" size and am trying it a bit lower. Last ride was at 26psi but I may go back up to 28.

I ride a lot of rocky, rooty trails, and I used to have to run around 40 psi to keep my 175 pounds from pinch flatting. This year I got a 29"er MTB and find that I can run around 28-30 psi without flatting. This lets me dive into the corners harder, brake better, climb with more traction, and not bounce around when I'm on the flats, definitely making my times faster.

I was riding with a group of 6 or 8 people the other day and this very topic came up. We did a quick survey of the people we had there, and found people running presures anywhere from 25psi to 60psi, and everyone seemed happy with what they had in their tires, so it seems to really depend on personal preference. I usualy run 30-35, and personaly dont understand the guy that runs 60, but hey it works for him, and untill I start leaving him in my dust im not going to say anything about how he chooses to inflate his tires.

Im running tubes, at about 40 psi and only have pinch flated once in the front. but this was on the mckinzie river trail (very rocky at times) so it was almost a given for how i ride (aggresive).