The days when we pumped up our tires to the maximum pressure – hoping to optimize performance – are long over.
Today we know that the best tire pressure depends on your tire size, your weight (and that of your bike), and your riding style and preferences. Lower pressures optimize comfort and tire grip. They also result in fewer flat tires: A soft tire often rolls over debris that would puncture a tire inflated to high pressure.
Tire Pressure Calculator
The calculator gives you two tire pressure recommendations. Use the ‘Soft’ value for gravel, rough pavement, or if you prefer a more comfortable ride. Use the ‘Firm’ value if you like your bike to have a firm feel. The ‘Firm’ values also provide a considerable margin of safety if your pressure drops a bit. With the ‘Soft’ pressure, you are stressing your tire casing more, and it may wear out faster.
Bicycle Quarterly’s extensive tire tests have shown that – on smooth roads – supple high-performance tires roll at the same speed at either of these two pressures. Pressures between these two values roll a little slower. On rough surfaces, your bike will be faster at the ‘Soft’ pressure.
This pressure calculator is intended only as guidance. Also remember that your pump’s gauge may not be accurate. When in doubt, use a tire pressure that feels right and safe to you instead of the values provided by the calculator.
Do not exceed the maximum pressure for your tire and/or rim. For tubeless installation, many tires have lower maximum pressures than what’s listed on the sidewall. Refer to the tire/rim manufacturers specifications.
Lower pressure means less vibration and less energy lost to suspension losses. That makes up for the higher hysteretic losses due to greater deformation of the tire.
These two factors – suspension losses and hysteretic losses – are not linear. The result: Mid-range pressures actually roll a little slower than either high or low pressures.
Based on Bicycle Quarterly’s tests of rolling resistance for different tire widths and pressures, together with Frank Berto’s measurements of tire drop under different weights, we have established two different tire pressure charts. These charts were translated into this Tire Pressure Calculator.
- More details about these tire pressure recommendations were published in Bicycle Quarterly 78.
- Some results of Bicycle Quarterly’s tire tests.
- The science behind the Tire Pressure Calculator.