Bike Tire Pressure Calculator
Tire pressure changes more on your bike than any other free adjustment: comfort, grip, speed and flat resistance. Enter your weight and your setup — you'll get a starting pressure matched to your bike, not an average printed on the sidewall.
That total, you + the bike, is what sets the pressure.
Mountain settings
Temperature correction optional
A tire inflated in the warmth loses pressure as it cools. If you inflate in a heated garage before heading out into the cold, these fields give you the pressure to aim for at the pump.
These values are a starting point, not a rule. Always respect the maximum pressure printed on the tire sidewall and on the rim. Then adjust a few psi at a time by feel — you're the one riding.
How to read your result
The calculator gives two numbers because your two wheels don't carry the same load. You sit behind the centre of the bike: the rear wheel takes more weight, so it needs more pressure. Inflating both tires to the same value is the most common mistake — and the easiest one to fix.
The useful range shown under the results is your room to manoeuvre. Within it, you adjust by feel: a few psi less for comfort and grip on poor roads, a few psi more if you feel the tire squirming in corners or bottoming out on potholes.
What actually changes your pressure
Your weight
This is the dominant factor, and it's why generic charts don't work. A 60 kg (132 lb) rider and a 100 kg (220 lb) rider on the same bike need very different pressures. Count your weight dressed, with your helmet, and add the contents of your bags if you ride loaded.
Tire width
The wider a tire, the more air it holds, and the less pressure it needs to carry you. That's the whole logic behind the shift to wider tires: a 32 mm at low pressure often rolls faster than a hard 25 mm, because it absorbs bumps instead of sending them back to you.
Your rim width
A wide rim spreads the tire and increases its real width. The same tire labelled 32 mm measures about 33 mm on a 21 mm internal rim, and close to 34 mm on a 25 mm rim. The calculator accounts for this: it's why it sometimes suggests a lower pressure than the manufacturer's chart.
The surface
On smooth asphalt, higher pressure reduces rolling resistance. As soon as the surface turns uneven, the logic reverses: a tire that's too hard bounces instead of following the ground, which slows you down and wears you out. On gravel, low pressure isn't a comfort compromise — it's what moves you forward.
Temperature
This is the factor almost nobody accounts for. Air contracts as it cools: a tire inflated to 70 psi in a 20 °C garage drops to around 63 psi once outside at −5 °C. In winter, or simply early in the season, that gap is enough to completely change how the bike behaves. Open the temperature correction in the calculator to get the value to aim for at the pump.
When to readjust
A tire naturally loses pressure, and the faster the narrower and harder it is. Check before every ride on a road bike, once a week on a mountain or city bike. A tubeless setup generally leaks down faster than an inner tube.
Readjust as well whenever something changes: new tires, new wheels, touring bags, or a temperature swing of more than ten degrees since your last inflation.
A reliable gauge beats a good calculation. The gauges built into floor pumps drift over time — if yours is a few years old, have it checked in store; our mechanics do it in seconds.