Tyre Pressure and Segment Time: The Underrated Lever
Harder is not faster. On real roads, and especially on farm tracks, the optimum sits well below what the sidewall says.
Why there is an optimum
More pressure reduces casing deformation but increases vibration losses, because bike and body get accelerated at every bump. Past a certain point those losses dominate — the tyre gets slower even though it is harder.
Reference values
For roughly 85 kg system weight and a 60/40 weight split, useful starting points are:
- 28 mm on smooth tarmac: 4.8 to 5.5 bar
- 32 mm on normal tarmac: 4.0 to 4.6 bar
- 38 mm on firm gravel: 2.8 to 3.4 bar
- 42 mm on loose gravel: 2.2 to 2.8 bar
Test, do not assume
Ride the same segment repeatedly with 0.4 bar differences at similar power. On rough surfaces, differences of five to ten seconds per two kilometres are common — a bigger effect than most equipment upgrades.
In short
Lower the pressure step by step until times stop improving — that is your optimum, not the manufacturer's number.
Frequently asked questions
Are wide tyres slower?
Not on rough ground, where they are usually faster. On smooth tarmac the larger frontal area costs a little aerodynamically.
Tubeless or inner tubes?
Tubeless allows lower pressures without pinch-flat risk, which usually makes it the faster choice on gravel.