The minimum and maximum tyre pressure range is embossed on your bike tyre sidewall.
Your bicycle rides on a cushion of air, courtesy of its pneumatic tyres – as long as your tyres are properly inflated.
The recommended maximum pressure is almost always embossed on the side of the tyre. Better still it might state both the maximum and minimum pressure – for instance ‘inflate from 70 to 120psi’ for a road bike tyre, or 20 to 40psi for a mountain bike tyre.
As a quick rule of thumb, inflate your tyre until it is half way between the minimum and maximum. If you consider yourself a “heavy” person, inflate it a little more, and if you consider yourself “light” then you can go with less. View the max as a safety measure – tyres can, and do, blow off quite spectacularly.
Pro tip: Next time you fix a puncture or change a tyre, line up the recommended PSI on your tyre with the inner tube nozzle. This makes the PSI quick and easy to locate next time you’re pumping up your tube.
What happens if I pump up my bike tyres too much/little?
Back in the day, the advice was to pump your tyres as hard as possible. The problem with this approach is that a tyre at maximum pressure has little give.
It is, literally, unforgiving. Tyres that are too hard will transmit every bump to your ass and your arms via the saddle and bars. And don’t even think about hitting a pothole.
Riding with the tyres too soft is even worse. They’ll “bottom out” over bumps so the wheel rim will be pushed straight into the inner tube, giving you a puncture and potentially also damaging your rims. Squidgy tyres will squirm unnervingly, especially when you corner, and they’ll wear out faster.
That’s why today’s enlightened rider aims for that sweet spot where the tyres are hard enough to keep their form and not bottom out, yet compliant enough to smooth bumps.
What is psi?
Air pressure is usually measured by psi, which means Pounds per Square Inch.
A skinny tyre requires much higher air pressure to keep its shape than a fat tyre. That’s why a road bike tyre might have to be inflated to over 100psi while 30psi will suffice for most mountain bike tyres.
A few caveats based on our experience
- If you’re below average weight, you can get away with lower pressures
- If you’re above average weight, inflating tyres to a slightly higher pressure makes sense
- Lowering tyre pressure in wet or icy conditions improves contact with the road so your tyres will grip better
- Remember – all tyres leak imperceptibly so if you do ride them close to their lowest recommended psi, best top them up once a week
- Owning a track pump with a pressure gauge makes it easy to keep your tyres up to optimum pressure. See track pumps
- Judging from the bikes that come into our shops for servicing, bicycles with underinflated tyres massively outnumber bikes with tyres at recommended pressure
- If you only inflate your tyres a couple of times a year, it’s probably not a bad idea to blow them up to maximum psi. At least then they’ll be above minimum pressure maybe half the year
Final thoughts on tyres
Even more than your bike’s frame, nothing influences the quality of the ride more than your bikes’ tyres and the amount of air they’re filled with.
The simplest way to improve the feel of almost any bike is to fit it with the widest lightweight tyres it can take, and run the tyres at optimum psi.
The latest research suggests that wider road tyres aren’t just more comfortable, they can also be faster – more on this.
Finally, the growing popularity of tubeless tyres, which can be ridden at lower pressure without risking pinch flats, offers further evidence that more and more riders are appreciating the benefits of riding at close-to minimum rather than maximum psi. See our blogs on tubeless mountain bike tyres and tubeless road bike tyres.