Tire pressure for road and gravel: chart by weight and tire width
The right tire pressure depends mainly on the load on each wheel and on tire width. Here you find a chart for common weights and widths, where the values come from, and where their limits are.
Tire pressure chart
Pressure in bar, front / rear. Total weight is rider plus bike plus luggage. Calculated with the typical 45/55 distribution and 15% tire drop.
| Total weight | 25 mm | 28 mm | 30 mm | 32 mm | 35 mm | 40 mm* | 45 mm* |
|---|---|---|---|---|---|---|---|
| 60 kg | 3.6 / 4.4 | 3.1 / 3.8 | 2.8 / 3.4 | 2.5 / 3.0 | 2.1 / 2.6 | 1.7 / 2.0 | 1.4 / 1.7 |
| 70 kg | 4.2 / 5.1† | 3.6 / 4.4 | 3.2 / 3.9 | 2.9 / 3.5 | 2.4 / 3.0 | 2.0 / 2.4 | 1.6 / 2.0 |
| 80 kg | 4.8 / 5.9† | 4.2 / 5.1† | 3.7 / 4.5 | 3.3 / 4.0 | 2.8 / 3.4 | 2.2 / 2.7 | 1.9 / 2.3 |
| 90 kg | 5.4 / 6.6† | 4.7 / 5.7† | 4.1 / 5.1† | 3.7 / 4.5 | 3.1 / 3.8 | 2.5 / 3.1 | 2.1 / 2.6 |
| 100 kg | 6.0 / 7.4† | 5.2 / 6.4† | 4.6 / 5.6† | 4.1 / 5.0† | 3.5 / 4.3 | 2.8 / 3.4 | 2.3 / 2.8 |
| 110 kg | 6.6 / 8.1† | 5.7 / 7.0† | 5.1 / 6.2† | 4.5 / 5.5† | 3.8 / 4.7 | 3.1 / 3.7 | 2.6 / 3.1 |
* above 37 mm extrapolated beyond Berto's data · † rear above 5 bar, not for hookless rims
Why wider tires need less pressure
A tire compresses under load. In the 1980s engineer Frank Berto measured 50 road tires at different pressures and loads. His result: the best compromise between rolling resistance, comfort and pinch flat protection is a tire drop of about 15% of the tire width. Bicycle Quarterly found in its own roll-down tests that tires stopped getting faster at roughly this pressure.
At the same pressure a wide tire compresses less relative to its width. Berto measured at 100 psi that a 20 mm tire compresses by 18% of its width, a 32 mm tire by only 10%. The narrow tire is too soft, the wide one too hard. For a 15% drop the wide tire needs much less pressure.
Example from the chart: at 84 kg total, 28 mm tires need 4.4 bar front and 5.3 bar rear, 40 mm tires only 2.3 and 2.9 bar.
Less pressure front than rear
What matters is the load on each wheel. The rear carries more weight. Berto calls 45/55 typical, Bicycle Quarterly measured 40/60 on a road bike and 35/65 with rear luggage. That is why the rear pressure comes out higher.
In practice many riders run almost the same pressure front and rear. Within about 0.3 bar that is fine. The difference matters mainly with luggage or heavy riders on narrow tires, where the rear would otherwise risk pinch flats.
Smooth tarmac or comfort
The 15% is a compromise. Berto describes it himself: a 13% drop means more pressure, less rolling resistance and a harsher ride. 17% means less pressure, a bit more rolling resistance and more comfort. On very rough roads or gravel less pressure can make sense, but the sources give no fixed reduction for it.
Hookless rims: 5 bar maximum
ETRTO and ISO set a maximum of 5 bar for hookless rims. Values above that on the rear are marked in the chart. If you would need that much pressure, a wider tire is the better choice. The maximum and minimum pressures printed on tire and rim always apply.
Measuring tire width
Berto used the actual measured width, not the label. On wide rims a tire often comes out wider than stated. Measure the inflated tire with calipers at the widest point of the casing and use that value.
Tubes or tubeless
The calculation does not distinguish between tubes and tubeless, and according to Silca the fastest pressure is the same for both. The difference is at the low end: with tubes, low pressure risks pinch flats, when the tube gets trapped between rim and obstacle. So with tubes do not go below the recommendation. Tubeless removes that risk, so you can lean towards comfort. The sources give no reliable figure for how much lower.
Where the values come from and their limits
Between Berto's data points from 19 to 37 mm our model matches his values exactly. He did not measure wider tires. There we extrapolate a contact patch model calibrated to his values. That is our own derivation and marked with an asterisk in the chart.
Berto's tires were tires of their time, with inner tubes. Supple modern tires compress more at the same pressure. Treat the values as a starting point and try 0.2 bar more or less.