What pressure should my bike tyres be?

Pressure is the single setting that most changes how a bike rides, and it is the one most often left to the maximum figure on the tyre. Higher pressure is not faster on real roads — beyond a point the tyre stops absorbing the surface and starts bouncing the whole bike, which costs both speed and grip.

Step by step

1. Read both numbers on the sidewall.Most tyres print a minimum and a maximum, in psi and often in bar. Never go above the maximum, and never below the minimum, which is set by the pressure needed to keep the tyre on the rim.
2. Check the rim's limit as well.Rims have a maximum pressure too, and on hookless rims it is often much lower than the tyre's. Whichever limit is lower is the one that applies.
3. Start from the width.Pressure and width trade off directly: a wider tyre supports the same load at a much lower pressure because it has a bigger contact area. Going from 25mm to 32mm typically drops the right pressure by 25 to 30 psi.
4. Adjust for your weight, including luggage.Total system weight is what the tyre supports. A 60kg rider and a 100kg rider with panniers want noticeably different pressures on the same tyre — as a rough guide, 10 psi more or less for every 15kg or so.
5. Adjust for the surface.Rough tarmac, gravel and wet roads all want less pressure than a smooth dry road. Lower pressure means the tyre conforms to the surface rather than skipping over it, which increases grip and, on rough ground, reduces rolling resistance rather than increasing it.
6. Put a little more in the rear than the front.Roughly 5 to 10 per cent more. Most of the rider's weight is over the back wheel, and a slightly softer front tyre gives better grip and comfort where you need it.
7. Check it weekly, with a gauge.Inner tubes lose pressure continuously, and a latex or lightweight tube can lose a third of its pressure in a week. Thumb pressure tells you almost nothing above about 40 psi; use a track pump with a gauge.
8. Recheck when the weather changes.Pressure falls with temperature, so a tyre pumped in a warm house is softer on a cold morning. It also rises on a hot day, which matters if you inflate to near the maximum.
9. Use the ride as the final check.If you feel every crack in the road and the bike skitters, drop pressure. If the tyre feels vague in corners, or you get pinch punctures, add some. Adjust in 5 psi steps and pay attention.

Tips

• A track pump with a gauge is the single best value tool a cyclist can own.
• Presta valves need the little nut unscrewed before pumping and done back up afterwards, or they leak slowly.
• Most punctures on a commuter bike come from running too soft. Weekly pressure checks prevent more punctures than any tyre.

Common mistakes

• Inflating to the maximum on the sidewall every time — The maximum is a structural limit, not a recommendation. A tyre at maximum pressure on a British road surface skips rather than absorbs, which loses grip, comfort and, on anything but glass-smooth tarmac, actual speed.
• Judging pressure by squeezing the tyre — The difference between 60 and 90 psi is essentially undetectable by thumb. People ride for months on tyres far softer than they think, which is how pinch punctures happen.

If it doesn't work

Questions people ask