Bicycle Tire Pressure Calculator

A tool that estimates the front and rear tire pressure (in psi) that suits your weight, bike, tire width, and riding surface, instead of guessing or copying a number off the tire’s sidewall — which only lists the tire’s safe maximum, not the pressure that actually suits your setup.

This calculator uses a formula built from Frank Berto’s published research: PSI = 153.6 × wheel load (lb) ÷ tire width (mm)^1.5785 − 7.1685, targeting roughly a 15% drop in tire height under your weight — the balance point most riders find comfortable and efficient. The result is then adjusted for tire type and terrain.

Yes — on a bike with a rider in a forward-leaning position, the rear wheel typically carries more weight than the front (often 55–60% rear), so it needs a few psi more to hit the same tire drop. Running identical front and rear pressure usually means the front is slightly over-inflated relative to the load it’s actually carrying.

Yes — tubeless setups can generally run lower pressure than the same tire with an inner tube, since there’s no tube friction dragging on rolling resistance and no pinch-flat risk from the tube getting caught between the tire and rim. This calculator applies roughly a 10% reduction for tubeless.

Rougher surfaces generally benefit from lower pressure: it lets the tire absorb bumps instead of transmitting them into the bike and rider, which improves comfort, control, and — on real-world rough roads — can even lower overall rolling resistance despite the tire itself flexing more. Very smooth pavement is the one situation where higher pressure has the fewest downsides.

They’re built differently, not more or less "correct." This calculator uses a published, reproducible formula from Frank Berto’s tire-drop research. SILCA’s calculator is based on their own proprietary field testing — finding the pressure "breakpoint" where rolling resistance and surface impedance cross over, across many tire and terrain combinations they’ve measured themselves. Both are reasonable starting points; neither replaces testing on your own roads.

It’s the benchmark Frank Berto used after measuring how much dozens of tires compress under load: at about 15% drop in tire height (roughly 20% drop in the height from rim to ground), most tires balance rolling resistance, comfort, and grip reasonably well. It’s a widely cited starting point, not a law of physics — see the Limitations section for its known caveats.

Not precisely — the underlying research measured tires roughly 20–45mm wide, and the formula extrapolates poorly to much wider MTB tires, sometimes suggesting unrealistically low numbers before the built-in safety floor catches it. Treat the result as a rough starting point for wide tires, and lean more heavily on your tire and rim manufacturer’s guidance.

Too high, and the tire can’t absorb small bumps, so it bounces and transmits more vibration into the bike — usually a harsher, less controlled ride, and on rough surfaces, not necessarily faster. Too low, and the tire deflects too much, increasing rolling resistance, risking a pinch flat or rim strike on a hard hit, and making the bike feel vague in corners. The calculator’s floor exists specifically to avoid recommending a pressure low enough to risk the second problem.

Yes — enter your gravel tire’s actual width (commonly 35–45mm) and choose "Gravel / light off-road" as the terrain. It sits comfortably within the width range this formula was built from, unlike full mountain-bike widths.