Bike Tire Pressure Calculator

Modern recommendations are much lower than the old high-pressure approach. A 70-80 kg rider on 28 mm road tires should typically run 65-75 psi rear and 60-70 psi front. Riders over 90 kg may need slightly more; lighter riders under 60 kg can go lower. Start with this calculator's recommendation and fine-tune by feel.

The rear wheel typically carries 53-55% of the total system weight on a road bike because of rider position and drivetrain weight. Higher load requires more pressure to maintain the same optimal contact patch shape. Running equal pressures means the front is over-inflated (reducing grip) and the rear is under-inflated (increasing rolling resistance and flat risk).

For 35-40 mm gravel tires on mixed surfaces, most riders in the 70-85 kg range run 28-38 psi rear and 25-34 psi front. Hardpack gravel allows slightly more pressure; loose or rough gravel requires less. Tubeless setups can run 5 psi lower than the same tire with a tube.

Yes, significantly. Wider tires at lower pressure can roll faster than narrow tires at high pressure on typical road surfaces because they conform to micro-texture rather than bouncing over it. The crossover point depends on surface quality. On perfectly smooth surfaces, narrow high-pressure tires are faster; on typical road or gravel, wider lower-pressure tires are often faster or equal.