TYRE PRESSURES

The air in your wheels made simple

The sweet spot

The best tyre pressure is one that’s low enough to give good traction and grip, with the tyre tread able to conform around and react to the terrain, but not so low that the tyre starts to roll off the rim or you begin to suffer pinch flats (where the tyre compresses so much upon impact that it hits the rim walls, causing parallel puncture wounds). Higher pressures may feel fast on tarmac and smooth trails, but they limit grip, and can lead to a bumpy and skittish ride off-road.

Rider weight and style

A heavier rider will put more force through their tyres than a lighter rider, so will need higher pressures. The same goes for aggressive riders, who really push their bike into turns and lips. Some folk are ‘heavy’ on their wheels – they ‘plough’ along the trail, leaving the bike to deal with any obstacles. They’ll need to run higher pressures than others who ride ‘lighter’, picking their way through with precision and choosing lines that are less punishing on tyres and rims.

Terrain types

Rocky trails are more likely to cause punctures than those with a soft, rooty or hardpack surface. A good rule of thumb is to increase pressure a touch for rides where you’re going to be encountering rocks, and reduce it to allow more tyre/terrain conformity on smoother surfaces.

Tyre/rim combos

Air pressure is inversely proportional to air volume. So, a wider tyre, especially one fitted to a broader rim, doesn’t need to be inflated to as high a pressure to achieve the same level of stability. Tyre casing and compound also play a part. Stronger sidewalls provide greater puncture resistance when compressed, allowing use of lower pressures. Conversely, softer rubber moulds to the ground better, so you can run higher pressures with less risk of losing grip.

Tubed/tubeless

Riders using inner tubes will need to run higher pressures than those running a tubeless set-up, because of the increased risk of pinch punctures and the slightly lower effective air volume (with the tube taking up space in the tyre).

Front/rear

Many riders run a couple of psi less in the front tyre than in the rear, to improve grip up front, while leaving the rear tyre firm enough to cushion/withstand drops and landings, and roll fast on smoother surfaces.

Fine-tuning

A good starting point is 1724psi (25-30psi if running tubes). From there, adjust to suit your weight, riding style, terrain and set-up.