There was a time when most riders would opt for 23c tyres on the road, pump the tyre pressure up to around 110psi for every ride, letting out just a little air to provide extra grip in poor weather.
With the increasing popularity of 25c tyres, and wider, the cycling community is gradually becoming more educated about the benefits of riding at lower pressure: increased comfort, better grip with an increased contact patch, and when paired with the right rim – improved aerodynamics.
However, there’s still a lot of debate surround tyre pressure and the ideal parameters for optimum performance – assessment being based on speed, ride quality and puncture resistance. So what’s the best approach?
Tyre pressure and rolling resistance
“It is true that the higher the inflation pressure, the lower the rolling resistance of the tyre,” Schwalbe UK’s Dave Taylor says. “It’s also worth pointing out that a tyre’s susceptibility to punctures is lower with high pressures, too. And if the inflation pressure is continuously too low, premature tyre wear is the result, which usually means cracking of the sidewall and unnecessarily high abrasion.”
So let’s cut to the chase: what tyre pressure should you actually be running?
“The ‘right’ inflation pressure depends on the load exerted on the tyre and the type of riding you are doing,” Taylor explains. “This load is the combined weight of the bike, the rider and any luggage. In addition, there is a great diversity of individual preferences with regard to rolling resistance and comfort.
“However, at Schwalbe we do have a very general guide for inflation pressure recommendations at three example rider weights. This is only a suggestion, though — riders should choose the pressure they put in their tyres to reflect the ride quality they want.”
What isn’t disputable is the rule that the narrower the tyre and the greater the overall load, the higher the necessary inflation pressure. Generally speaking, for each additional kilogram that the tyre must carry in terms of combined bike, rider and luggage weight, tyre pressure should be increased by one per cent.
Schwalbe’s recommended tyre pressure
Tyre pressure, contact patch and grip
Tyres with very small diameters, such as those found on recumbents or folding bikes, also require a higher pressure. And, whatever your preference, tyre pressure should always lie within the maximum and minimum inflation recommendations marked on the tyre sidewall.
For all the talk of high pressures, let’s not forget that low tyre pressures have their place, as Ben Blaurock of Continental Tyres explains:
“If you reduce a tyre’s pressure, its tyre contact patch will increase. This increases the grip level and if you are riding in wet conditions, a bit lower pressure than usual — around 0.5 bar [7psi] — is recommended.
“Lower pressures can also offer increased comfort. Although, be careful not to drop your tyre pressures too low as this also increases the risk of ‘snake bite’ punctures — where the inner tube is trapped between the wheel rim and the tyre,” Blaurock says.
“If you are a very heavy rider, inflate to either maximum pressure or no less than maximum pressure minus one bar [15psi] to reduce the risk of snake bites, especially with bad road conditions.
“Finally, don’t forget that the biggest downside with lower tyre pressures is an increase in rolling resistance.”
And this is where the great benefits of wider tyres come into play. Wider tyres are generally used at lower pressures, which, combined with their larger air volume, means they absorb road bumps and holes better and are therefore more comfortable to ride. Crucially, though, wider tyres don’t suffer from reduced puncture protection, or increased tyre wear and, perhaps surprisingly, don’t even have higher rolling resistances.
“Because the length of contact patch of a 25c tyre is shorter than the contact patch of a 23c tyre at the same pressure, there is less tyre deflection and therefore less rolling resistance,” Blaurock explains.
“This, allied with the fact that wider tyres can provide more comfort is the reason why we are seeing wider tires becoming more popular.”
If you’re searching for outright performance and high average speeds, though, higher tyre pressure is still where the answer lies. Blaurock says: “As we know, the higher the pressure, the lower the rolling resistance.
“If you have great road conditions and you would like to ride very fast — in a race, for example — inflate to the maximum permitted pressure. Using the example of a 25c tyre, you can reduce rolling resistance by around 10 per cent simply by using 8.5 bar [123psi] instead of 6.5 bar [94psi].”
So how much should you inflate your tyres? That’s really up to you to decide.
The basics: how to pump your bicycle tyres
For the beginners among our readers – here’s how to actually get air into your rubber:
- Buy a track pump to store at home. You’ll need to pump your bicycle tyres around once a week – and though a mini pump will suffice, it’ll take you a lot longer to reach the desired pressure (though you’ll get very toned arms)
- Know what tyre pressure you want to reach. The maximum tyre pressure will be displayed on the tyre sidewall. The maximum tyre pressure will be lower the wider the tyre – but lighter riders will run slightly lower pressure, and you should also let some air out if the ground is wet or the road surface less than ideal
- Ensure that you’re using a pump that is compatible with your valve type. Most pumps can connect to Presta and Schrader valves, and just need to be set to the correct mode
- Remove the dust cap on your inner tube – this is the small bit of plastic over the top of a new tube
- If you’re pumping up a Presta valve, untwist the screw at the valve tip – not enough to actually remove it, but enough so that it’s in the ‘open’ position
- Clamp the head of the pump over the valve – the method required for this varies depending upon the style of pump. Some require you to pull a small lever, whilst others twist on
- Pull the lever of your track pump, and push down fully, before repeating – the pressure gauge should show the PSI increasing. If not, try taking the nozzle off the valve and replacing
- Keep going until you reach the desired tyre pressure
- Remove the clamp from the valve, carefully – and tighten the screw by hand. You can return the dust cap if you like, though most riders choose not to
- If your old inner tube had a puncture – check out this guide on how to repair a puncture