What is the best Bike tyre pressure?
A very good question with a not so straightforward answer.
Tyre recommended pressure range will be written on the sides of your bicycle tyres and will usually give a range such as 70-120 psi for road bikes and 20-40psi for some mountain bikes. A general rule is that the higher the psi, the less rolling resistance you will get (you'll be faster) but the more you will feel the road as vibration damping decreases as the psi increases. There are also different considerations for different styles of bikes to obtain the optimum tyre pressure so we will discuss each in turn below.
It is worth noting here that it is worth having a good quality track pump (also known as floor pumps) with a built in air pressure gauge so you know the pressure in your tyres. Track pumps will also allow you to pump to higher pressures easier. Some hand-held pumps have a pressure gauge also but it is harder to pump tyres up to high pressure using these.
Road and hybrid Bikes
Too hard
Back in the day, the advice was to pump your tyres to maximum pressure in order to be as fast as possible (particularly on road bikes). The problem with this approach is that this only works on pristine tarmac (a.k.a not Britain!). If the road surfaces are less than ideal, it is best to run your tyres at a lower pressure as this will allow your tyre to remain in contact with the road and will transfer more of your power into propelling you forward.
Too soft
If you run your tyres too soft, you risk what we term as a 'pinch flat' - this is where you hit a bump in the road and the tyre compresses enough to pinch your inner tube between the tyre and the wheel rim, resulting in a puncture and some roadside maintenance (did you remember your spares?).
Just right
The right pressure, therefore, is the one where you are not risking a pinch flat and you are happy with your efficiency/comfort balance. There is also the option to run the front tyre at a slightly lower pressure than the rear tyre. This is for two reasons, 1) The rear wheel carries more of the weight than the front wheel and, 2) typically, the front tyre gives cornering grip and the rear tyre is for efficiency.
Tubeless considerations
Tubeless tyres setup is a relatively new technology and came from the mountain biking world. If you are set up tubeless, you can run tyres at even lower pressures to allow you more comfort without the risk of the pinch flat. Please bear in mind that you still need to be careful not to go too low as to allow the rim to be damaged on hard impacts (read: potholes). You will also get fewer punctures running tubeless.
Mountain and gravel bikes
Mountain bikes and gravel bikes are slightly different due to the surface you are riding on. The principles remain the same from the road and hybrid section but there are other benefits.
Too hard
Running a tyre that is too hard on these bikes will affect the amount of traction you get while cornering on loose surfaces and mud. Mountain bike and gravel cyclists will generally run their pressures lower to give more grip on the corners of technical descents.
Too soft
The same issues appear if your tyre is too soft - you risk pinch flats (if you are running inner tubes) and for cross country style riding you become less efficient as your tyre pressure gets lower. So for certain types of mountain and gravel bikes, a higher pressure will be beneficial.
Just right
Depending on the type of riding you are doing will depend on the psi you will run. Again, it is about getting the balance right but this time it is between efficiency and cornering traction.
Tubeless considerations
The vast majority of mountain and gravel riders are choosing tubeless tyre setup to allow lower pressures without the risk of pinch flats to enable them to corner faster on gravel and mud. Fewer punctures that will end your ride is always nice too.
A few caveats based on our experience
If you’re below average weight, you can get away with lower bike tyre 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 the correct tyre pressure
FINAL THOUGHTS ON BIKE TYRE PRESSURE
Well... we said it wasn't an easy answer but hopefully this helps in understanding the trade off's of running higher/lower pressures in your tyres and which setup will help make your bike work better for you. We can see that the correct tyre pressure can be determined by-
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The discipline of riding you are doing (road bike tyre pressure will differ greatly from mountain bikes tyre pressures)
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The style of riding you are doing (downhill Mountain bikes vs cross country mountain bikes tyre pressure)
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Whether you are running tubeless tyres or an inner tube.
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Where on the scale of the comfort/efficiency trade-off you sit.
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Rider weight