People run wildly different pressures in their mountain bike tires, for all sorts of reasons. The best tire pressure for you depends on many factors that are personal to you - which is why there is no simple way for us say "this is the right pressure for you". Things such as tire selection, suspension setup, rider skill level, local terrain and many other factors can impact what pressure you should run on a given day.
The air in your tires has an important job, so your tire pressure should be checked before every ride since it is normal to lose air thru the tire casing, even overnight!
Here is a calculation which we recommend as a starting point:
Pbase = (your weight in lbs.) / 8
Front tire pressure in PSI= Pbase
Rear tire pressure in PSI = Pbase + 3
See Table below for calculated values!
For ebikes, considering the additional weight we recommend +3 PSI to above values
If you stopped reading now and you inflated your tires to those pressures, you'd be able to ride your bike, and the performance would probably be okay, and you'd be unlikely to dent or damage your rims.
Once you have that baseline pressure set in your mind, you can start experimenting with your pressure. The right pressure for you could be more or less than what you ended up with using the above equation. If you decide you want to let air out, you need to be acutely aware of what a rim impact feels like when riding. If your rim is contacting the ground through your tire (impact), your tire pressure is too low and you are risking a rim failure.
Things to consider as you start to experiment:
- We ALWAYS recommend using a digital pressure gauge. Don't rely on the potentially suspect analog gauge on your pump or "tire feel" by compressing the tire with your hands.
- Tire sidewall construction - heavier sidewall tires can generally run lower pressure
- Tire Volume - wider, larger diameter tires hold more air, which will develop a lower spring rate
- Tire Profile - tires with square tread profile may need a little more air to roll fast, while rounder tires may allow slightly lower pressure
- Tire inserts may help reduce the possibility of rim damage. Some inserts like Cushcore will also provide casing stability. When running inserts which provide casing stability, it is critical to not reduce pressure more than 2 PSI from your correct non-insert pressure. Even with inserts, you can still damage or crack a rim if your pressure is too low.
Keep in mind the role of air in your tires as you are experimenting:
- Absorb impacts like a spring and protect your rim
- Support the casing and stiffen the tire under side/turning loads
- Stiffen the carcass to reduce knob deflection under braking and turning
- Absorb and blunt vibrations before they reach you
- Maintain the tire cross-section to reduce rolling resistance while rolling, pedaling and braking
- Probably other things
Reference Table:
Weight (lbs) | Weight (kg) | Front Pressure (psi) | Rear Pressure (psi) |
Under 100 | Under 45 | 12.5 | 15.5 |
100-110 | 50-45 | 13.75 | 16.75 |
110-120 | 55-50 | 15 | 18 |
120-130 | 59-55 | 16.25 | 19.25 |
130-140 | 64-59 | 17.5 | 20.5 |
140-150 | 68-64 | 18.75 | 21.75 |
150-160 | 73-68 | 20 | 23 |
160-170 | 77-73 | 21.25 | 24.25 |
170-180 | 82-77 | 22.5 | 25.5 |
180-190 | 86-82 | 23.75 | 26.75 |
190-200 | 91-86 | 25 | 28 |
200-210 | 95-91 | 26.25 | 29.25 |
210-220 | 100-95 | 27.5 | 30.5 |
220-230 | 105-100 | 28.75 | 31.75 |
230-240 | 109-105 | 30 | 33 |
240-250 | 114-109 | 31.25 | 34.25 |
**For E-Bikes - consider the additional weight of the bike, and add 3 psi to be safe!**
*equation stolen <ahem>, adapted from ye olde Stan's Pressure Method