The amount of air pressure that you put in your tires greatly affects the riding characteristics of your bike.
When MTB Tire Pressure Is Too High
- Bike bounces off of obstacles
- Poor cornering performance
- Tires break loose easily
When Tire Pressure Is Too Low
- Greater chance of pinch flatting
- Efficiency loss while pedaling
- Roll over can cause unpredictable handling
So How Do I Find My Ideal Pressure?
One thing to remember is that your tires are also part of your suspension. Your tires are also your only contact with the trail, so it is very important to figure out your pressure range to get the best performance and comfort.
There are generally a couple of rules to consider.
- Heavier riders need higher pressures (the opposite is true for lighter riders).
- Lower volume tires (1.8-2.1) need higher pressures while high volume tires (2.2+) need lower.
- Thicker sidewall (heavier) tires ride better with lower pressures than higher.
- Tubeless setups run lower pressures than tubed.
While these “rules” create a great starting point, it is always important to remember that results vary based on riding style, tire brand and trail conditions. Once you find your optimal + 5 psi range, you can adjust to the trail conditions easily and quickly.
Ideally, you want to run the lowest pressures that you can get away with without pinch flatting. Using the list above as a gauge, start with a high pressure (around 45 psi) using a floor pump. Use this same floor pump throughout the test. Ride at this tire pressure for awhile on the trail and observe the results. Now, go back to the car and lower the pressure 5 psi. Repeat the same process observing the results.
At lower pressures, you are going to notice more grip and a softer ride. You want to run the pressures low enough that you get these benefits but not so low that you experience pinch flats. Pinch flats occur when the tire bottoms out on the rim pinching the tube between the ground and the rim. This punctures the tube and causes a flat. You can normally feel the hard bottom out when you are riding over a rock or root.
Keep repeating this process until you find the pressure that fits your riding style and tires the best.
For tubeless systems (UST or Converted), you do not have to worry about pinch flats, but you can experience roll over due to lower pressures. It is ok to contact the rim occasionally under hard hits, but make sure that you are not damaging the rim. Too low of pressures can cause the tire to roll over on itself and this creates an unpredictable cornering ability. Generally, tubeless systems are going to run 5 – 7 psi lower than comparable tubed tires.
How Much Pressure Do I Run In My Tires?
I run a lot of different tires on a lot of different bikes, but surprisingly…my pressures are pretty close to each other in all conditions. I have a 190 lbs. riding weight for reference.
- Larger Tires Tubed (2.3+) = 28 – 30 psi
- Smaller Tires Tubed (2.25) = 30 – 32 psi
- Larger Tires Tubeless (2.3+) = 26 – 28 psi
- Smaller Tires Tubeless (2.25) = 27 – 28 psi
As you are probably noticing from the list, I do not run a tire under 2.25 in size. I do not see any benefit from running a tire any smaller. With today’s tires, you are able to get more volume and control at a weight that used to only be available to the small tire lines. More riders are getting converted to larger volume tires on a daily basis because the weight has become acceptable to more xc oriented riders.
I ran into a tire recently, Maxxis Ardent 29 x 2.25, that ended up running the best at 25 – 26 psi tubed, so be sure to remember that results can vary depending on tread design.
P.S. – One last thing…everyone has their own opinion about how much pressure you should be running in your tires. They are probably wrong (especially the guys that claim that 50 psi is the only way to go!). Do your own testing and get your own results. Tire pressure is heavily dependent on numerous factors that change as you change…keep on testing!