Bike Tire Pressure Calculator

Front and rear PSI by weight and widthRuns locally · nothing uploaded

Bike typeRider weight (kg, with kit)Bike + luggage (kg)Measured tire width (mm)Actual inflated width; often 1–2 mm wider than the label

Unit

Front

47 psi

Rear

74 psi

System weight

79 kg

Suggested pressure by tire width

Width	Front	Rear
23 mm	67 psi	104 psi
25 mm	58 psi	90 psi
28 mm	47 psi	74 psi
30 mm	41 psi	66 psi
32 mm	37 psi	59 psi

A starting point that gives about 15% tire drop under load, not a maximum. Never exceed the tire or rim limit; hookless rims are usually limited to 5 bar (72.5 psi). Drop 5–10% in the wet.

A starting point from an empirical formula. Never exceed the maximum pressure marked on the tire or rim.

Also works as:road bike tire pressure28mm tire pressuregravel tire pressuretire pressure psi bar

How it works

Formula

Wheel load: road 40% front / 60% rear; gravel 42% / 58%

psi = 153.6 × wheel load (lb) ÷ width (mm)^1.5866 − 7.1

A fit of Frank Berto's 15% tire-drop chart.

Worked example

Given: Road bike, 70 kg rider, 9 kg bike, 28 mm tires

Front 31.6 kg (69.7 lb), rear 47.4 kg (104.5 lb).
Front ≈ 47 psi, rear ≈ 74 psi.

Result: About 47 psi front (3.24 bar) and 74 psi rear (5.11 bar).

Limitations

Fitted on 20–37 mm road tires; not for MTB.
Never exceed tire or rim limits.

Sources

Berto F. The 15% Tire Drop Rule. Bicycle Quarterly. 2006.

How to use

1Choose the bike type and enter rider and bike weight.
2Enter the measured inflated tire width.
3Read front and rear pressure and fine-tune by feel.

FAQ

What pressure for 28 mm road tires?

For an 80 kg rider-plus-bike system, about 48 psi front and 75 psi rear (3.3 / 5.2 bar).

Is higher pressure faster?

Not on real roads: too much pressure makes the bike bounce, losing energy and grip.

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