The Guide to Bike Tyre Pressure (For Road & MTBs)Learn how to adjust your tyre pressure for the type of ride and the conditions, and have a great ride every time.
Does the topic of tyre pressure leave you deflated? This advice should pump up your confidence.
Riding a bike is like floating on air — almost quite literally because all that’s between you and the road is a thin circle of rubber full of air. Tyre pressure affects your speed, traction, and overall ride enjoyment so getting it right can make the difference between a carefree Saturday morning spin and a suffering slog around your favourite loop. When it comes to tyre pressure, you can’t just “set it and forget it” because tyres lose air over time for a variety of reasons. You’ll soon learn that it’s not such a mystery once the truth about road cycle tyre pressure gets revealed.
Bicycle tyre pressure is a measurement of the air — calculated in PSI or bars — that’s been pumped into your tyres. PSI (pound per square inch) is a pressure unit resulting from a 1-pound force applied to an area of a square inch. A bar, on the other hand, is a metric unit of atmospheric pressure at sea level. You’re likely familiar with PSI if you’re used to the imperial system of measurement, or bars if you measure things in metric.
To tell you the truth, tyre pressure can massively impact the quality of your ride. It’s first and foremost a safety issue, as the wrong pressure can lead to a burst tyre. It’s also a matter of comfort Don’t be shy about experimenting with your tyre pressure because ultimately, you’re the only person “under pressure” to make your bike perform at its best!
Previously there were set ‘rules’ as to the correct road bike tyre pressure being 120 psi or more, with a 23mm tyre the norm and 25mm seen it to be huge. There has, however, been a move in consensus. Instead of looking for the perfect bike pressure, it now more about looking for the ideal one. It’s about finding the right balance between reducing rolling resistance and increased comfort, which means that you can look to let your tyre sag, to optimise the ground contact area and therefore impact maneuverability and performance. Views on the correct tyre size have also changed, with 25mm now seen as narrow and the standard sizing now goes from 28mm up to 32mm. Many experts believe this crucial to getting the pressure right, and that while it used to be believed that the higher the pressure, the faster the bike, it’s now thought that the wider the tyre, the lower the pressure. Rider weight, their normal riding stance, their style, and road/atmospheric conditions all must be also taken into account. So most importantly, do what feels right for your riding!
Similar to that of road bike tyres, the right pressure for mountain bike tyres does depend on that of the rider. Also similarly to road bikes, the lower the pressure tyre (within reason) the better. It was previously a case of pumping them up as much as possible, however, it is now believed that a little give makes them more adaptable to unpredictable terrains, such as roots and rocks. It also helps with traction for both climbs and descents. To start things off, begin with the base settings above and add 3-5 psi front and rear. This approach should work with most modern tyres, and they won’t need high pressures to maintain their shape and corner well. Saying all this, there is certainly a level at which you can take your mountain bike tyre pressure too low, which can lead to the increased likelihood of rim damage, reduced natural spring which can lead to unstable riding, and a lack of stability in the sidewheel that can lead to ghost steering. It’s all about finding the right balance between enough protection for your wheels’ rims and good traction when going around corners. It’s also worth remembering that the wider your wheels rims, the more sport your tyres are given, w
The writing on the (side) wall – Your tyre’s sidewall should have the recommended tyre pressure in PSI or bars printed or moulded into the rubber on one side or the other of the tyre tread. If the text is moulded into the sidewall, you’ll have to look closely because it tends to blend seamlessly with the tyre, which can also make it a bit hard to read.
Peer Pressure (tip: don’t give in!) – There’s no “one size fits all” tyre pressure because things like rider weight and riding surface affect your ideal tyre pressure. In general, properly inflated tyres are safer and more efficient, and will last longer than over-or underinflated tyres — we’ll get into that more below. Since such variables exist, recommended tyre pressure is usually listed as a range. It helps that most bicycle pumps conveniently have a pressure gauge that measures the pressure in both PSI and bars.
While much of finding your ideal bike pressure is down to the type of bike and the terrain you will be riding on, it’s also about finding what works best with your weight and height. In practical terms, the heavier you are, the faster the tyre pressure will decrease, when compared to a lighter rider, which is why it’s good for bulkier cyclists to have higher pressure in their tyres. As said previously, you’ll want to find the sweet spot with good traction and tyre deformation isn’t making for sluggish handling, and pinch flats aren’t a worry when cycling on uneven roads, yet your tyres still has enough cushioning for comfort. A good rule of thumb in cycling circles is to take approximately 10% of the combined weight of you and your bike in kilos. For example, an 80kg rider on an 8kg bike, should look for 127.6psi, and the front should be slightly less than the rear to make up for your weight distribution. But after that, it’s all about trusting your instinct.
We’ve said a lot about the belief that low tyre pressure is healthy tyre pressure, but how can you be sure it’s right? If you have too much air in your tyres, you’ll start to feel like you’re bouncing over the road instead of rolling over it. Overinflated tyres can also cause you to underestimate braking distances and lose traction, especially if the road is wet. To deflate your tyre, remove the valve cap and press on the valve’s core with your fingernail. Be careful not to deflate it too much, otherwise, you’ll run into the problems listed in the next section.
While it can be tricky getting a sense of when your tyre pressure is too high, it shouldn’t be as difficult when trying to work out if your tyre pressure is too low. Tyres that are too soft will make you work harder to maintain momentum because more of your tyre’s surface area will be in contact with the road, which will take more effort to keep you rolling. Low pressure will also make your tyres more prone to puncturing, and they will wear out faster. This is an easy fix with a floor pump or a ride-along pump, just pump up your tires to within the recommended range and you’re good to go!
Make sure this is handled properly, as failure to do so can lead to pinching a flat. This is when the tube gets squeezed between the rim and tire casing after hitting a bump with an underinflated wheel. Not only does will this damage the wheel, but it will also cause harm to the rim, and lead to a tougher cycling experience, which is the last thing anyone wants when riding.
How to handle the pressure
Managing tyre pressure is one of the easiest (and cheapest!) ways to elevate your ride experience. Once you’ve learned the basics, you can start incorporating your personal pressure preferences into every ride, all you need is a bicycle pump with a pressure gauge.
Using a Pressure Gauge
This is the device for measuring the amount of pressure a tyre releases. As the air fills up in the tyre, it will also enter the pressure gauge. This, in turn, will activate the gauge’s internal mechanism, and the psi (pounds per square inch) will be shown on the meter gauge in question. Pressure gauges come in both manual and digital forms and shown here.
Using a Bike Pump
As it’s a good idea to be regularly checking your tyre pressure, this a piece of equipment that’s vital to getting your tyre pressure just right. Getting the ideal PSI does sometimes some finesse, and that’s also about getting the basics right. When choosing a bike pump, make sure you pick one that works with the tube valve on your bike. There are two popular types, the Shrader valve, which is wider and flat on the end, and the Presta valve is narrower and features a locking nut at the top, which can be loosened to either add or release air. It’s important to get this right, as the wrong valve can render your pump useless. Once you have this right, remove the plastic cap off the top of the valve, and check the sidewall for your tyres’ PSI range. It’s usually the case that a tyre for a road bike goes between 80 and 130 psi, while a mountain tyre can hold between 25 and 50 psi. Next up, it’s time to attach your pump to the valve. The pump will usually either be an internally threaded screw top or a switch that flips down or up. Both of these systems help keep the head in place whilst you’re pumping and make sure the air is going into the tyre instead of leaking out. If the air is coming out, you may need to double-check your pumping. For efficient pumping, use your upper body and core (it can feel like a mini workout). Keep an eye on the gauge to find your optimal pressure.
There is a wide range of different types of bike pumps. Find the right one for you, right here.