Bike Tire Pressure Calculator
Front and rear tyre pressure from your weight and tyre width, with the hookless and sidewall limits applied — not one number for the whole bike.
A starting point, not a prescription. Ride it, then adjust by a few psi at a time until it feels right — that is the only test that counts.
What decides the number
- Tyre drop is the real target — how far the tyre squashes under load, around 15%. Everything else here is a way of getting there.
- Width matters more than anything. Going from 25 mm to 32 mm drops the right pressure by roughly a third at the same weight.
- Measure your tyre. A tyre marked 32 mm can measure 34 mm on a wide rim, and the pressure follows what it measures, not what it says.
- The front takes less than the rear because it carries less. Running them equal means one end is always wrong.
- Rougher ground wants less pressure, not more. Above a certain point a harder tyre bounces instead of conforming, and both grip and speed fall.
How to use
- Enter your weight in the kit you ride in, plus the bike and anything you carry on it.
- Measure the tyre with calipers rather than trusting the number printed on it.
- Set the surface, and tick tubeless or hookless if they apply.
- Read the front and rear figures separately — they are not the same.
- Ride it, then adjust a few psi at a time until it feels right.
Frequently asked questions
Why are the front and rear different?
Because they carry different loads. A seated rider puts roughly 55 per cent of the total weight on the rear wheel, and holding the same tyre drop at a heavier load needs proportionally more pressure. Running both ends the same means one of them is wrong — usually the front, which ends up harsh and short of grip.
What is tyre drop and why does it decide the pressure?
How far the tyre squashes under load, and it is the thing pressure is really setting. Around 15 per cent of tyre height is the long-standing target from Frank Berto's rolling resistance work. Everything else here — weight, width, surface — is a way of arriving at that drop.
Why does a wider tyre need so much less pressure?
Because it holds more air and supports the load over a larger contact patch, so it reaches the same drop at a much lower pressure. Going from 25 mm to 32 mm cuts the right pressure by roughly a third at the same weight, which is why fitting wider tyres and keeping the old pressure produces a bike that rides worse than before.
What is the hookless limit and why is it absolute?
ETRTO caps hookless rims at 5 bar, or 72.5 psi, regardless of what the tyre is rated to. A hookless rim has no bead hook to retain the tyre, so above that pressure it can blow off the rim entirely. Where the calculation exceeds it, the answer is a wider tyre rather than more pressure, and this tool caps rather than recommending past it.
Does running lower pressure make me slower?
On smooth tarmac, slightly. On anything rough, usually not — past a certain point a hard tyre stops conforming to the surface and starts bouncing, and the energy lost to that vibration exceeds what you save in rolling resistance. This is why professional riders have moved to wider tyres at lower pressures rather than the opposite.
Can I run these pressures with inner tubes?
Down to about 35 psi, yes. Below that a tube pinches against the rim on impacts and flats easily, which is why the low figures for gravel and mountain widths assume tubeless. The tool says so when the result lands there rather than letting you find out on the trail.
How accurate is this?
It is a starting point and says so. Tyre casings differ, a tyre marked 32 mm can measure 34 on a wide rim, and riders genuinely differ in what feels right at the same drop. Use it to get close in one step instead of five, then adjust by feel — that last part is not something a calculator can do for you.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.