Posted in Cycle and tagged safety
bicycle tyre pressure guide

The pressure that you choose for your bicycle tyres, whether it is a road bike, mountain bike, or hybrid, plays a huge part in comfort and safety.  

In this guide, we look at how to get the best tyre pressure for your riding style and conditions.  

The importance of tyre pressure on bicycles

Tyre pressure has two primary impacts on how your tyres perform: first, it affects grip; second, it affects rolling resistance.

Grip levels 

The more that a tyre can conform to and make contact with the surface that it is rolling over, the greater the grip level that it achieves. This means that an over-inflated tyre that bounces over a surface and rolls only on the central strip will not have good grip. 

Rolling resistance 

Rolling resistance is how much friction occurs between tyre and surface; the greater the friction, the greater the resistance. An underinflated tyre will provide too much contact with the surface, and therefore too much rolling resistance. Perhaps surprisingly, an over-inflated tyre also increases rolling resistance; because it constantly bounces on the surface, rather than rolling smoothly along it. 

To achieve the best grip level and rolling resistance level, it is vital to get the correct tyre pressure in your bike tyres. 

Inner tube vs. Tubeless tyres 

When considering tyre pressure, you have to take into account whether you have clincher tyres fitted with inner tubes on your bike, or whether you have tubeless tyres.  

Tyres with inner tubes can be more subject to 'pinch flat' punctures if you run a low pressure; this occurs when a large impact on the tyre causes the tyre's bead to pinch the inner tube and puncture it. 'Pinch Flats' are not possible on tubeless tyres, because there is no tube to pinch.

Because of the risk of inner tube pinch flats, sometimes you need to run a slightly higher pressure than would be optimal in an inner tube set-up, to reduce the risk of puncturing.

The correct tyre pressure guide 

The best tyre pressure for your bike will depend on the kind of bike you have, the kind of tyres you have fitted; and also factors like rider weight, road conditions and weather conditions.  

Mountain bike tyre pressures 

Mountain bike tyres are run at a lower pressure than road tyres so that the tyre can conform to the terrain, and provide added grip.  

The added volume in a mountain bike tyre means despite these lower pressures, it is less likely to pinch flat. 

Suggested tyre pressure for mountain bike tyres - for a ≤70Kg rider: 

  • Inner tube tyre: 36PSI (2.5Bar) Front / 38PSI (2.6Bar) Rear 
  • Tubeless tyre: 26PSI (1.8Bar) Front / 28PSI (1.9Bar) Rear 

Adjust for weight: 

  • Add 1 PSI for every 5Kg over 70Kg  

Road bike tyre pressures 

Road bike tyres are run at a higher pressure than mountain bike tyres, to reduce rolling resistance and the chance of 'pinch flat' punctures.  

Suggested tyre pressure for road bike tyres (25mm) - for a ≤70Kg rider: 

  • Inner tube tyre: 90PSI (6.2Bar) Front / 93PSI (6.4Bar) Rear 
  • Tubeless tyre: 80PSI (5.5Bar) Front / 83PSI (5.7Bar) Rear 

Adjust for weight: 

  • Add 2PSI for every 5Kg over 70Kg 
  • Subtract 2PSI for every 5Kg under 70Kg 

Cyclocross/Gravel bike tyre pressures

Cyclocross tyres are run at a higher pressure than mountain bike tyres, but a lower pressure than narrower road bike tyres; providing the best compromise between grip and rolling resistance. 

Here's James with a thorough guide to figuring out the right tyre pressure for you. 

Suggested tyre pressure for cyclocross tyres (35mm) - for a ≤70Kg rider: 

  • Inner tube tyre: 48PSI (3.3Bar) Front / 50PSI (3.5Bar) Rear 
  • Tubeless tyre: 36PSI (2.5Bar) Front / 38PSI (2.6Bar) Rear 

Adjust for weight: 

  • Add 1PSI for every 5Kg over 70Kg

Hybrid/City bike tyre pressures

A hybrid bike tyre is similar in volume to a cyclocross tyre, so the pressures are also similar: 

Suggested tyre pressure for city bike tyres (35mm) - for a ≤70Kg rider: 

  • Inner tube tyre: 50PSI (3.4Bar) Front / 55PSI (3.8Bar) Rear 
  • Tubeless tyre: 38PSI (2.6Bar) Front / 40PSI (2.75Bar) Rear 

Adjust for weight: 

  • Add 1PSI for every 5Kg over 70Kg 

Tyre pressure for turbo trainers

Riding using a turbo trainer removes many of the benefits lower tyre pressure provides. In fact, there are few reasons to want to reduce your tyre pressure on a turbo, while it may adversely affect the power output registered by your trainer.

Generally, 100 PSI is the standard pressure setting for a wheel-on turbo, but this can be reduced by 10 PSI or so if you're experiencing a lot of tyre slippage.    

Adjusting tyre pressure for wet conditions 

Many riders advise that they drop their tyre pressure in wet riding conditions.  

In reality, the necessity to do this is not that great, assuming you have the correct tyre pressure initially. After all, most people (including professional bike racers) would not stop mid-ride and lower their pressures if it began to rain.  

If you do decide to lower your tyre pressure from the above recommendations, then do so by only 2 PSI; any significant reduction may actually cause the tyre to squirm more, making it unstable on the road or trail surface. 

Refining your ride 

The above numbers for recommended bike tyre pressure are fairly specific, and some riders may say there is no hope of their pump (especially their hand-pump) of being that accurate. 

The good news is that with the advent of digital gauges on floor pumps and hand pumps, the accuracy of your tyre pressure inflation can be really on point.