Why use total system weight, not just my body weight?

The tyres carry everything: you, your kit, and the bike. A light rider on a heavy touring bike loads the tyres far more than body weight alone suggests, so pressure must be set from the combined total to avoid pinch flats.

Why is the rear pressure higher than the front?

Seated riders carry roughly 60 percent of their weight on the rear wheel and 40 percent on the front. Because the rear tyre supports more load, it needs proportionally higher pressure to deflect the same amount and resist pinch flats.

Does wider tyre mean lower pressure?

Yes. A wider tyre holds more air volume, so it supports the same load at lower pressure. Modern wide road and gravel tyres run far softer than narrow tyres of the past while rolling faster and gripping better on rough surfaces.

How does surface type change the recommendation?

Smooth tarmac tolerates higher pressure for low rolling resistance, while gravel and mountain biking need lower pressure for grip, comfort, and to absorb impacts. The tool scales the base pressure down for rougher surfaces.

Should I adjust for tubeless versus tubes?

Tubeless setups can safely run a few psi lower than the same tyre with an inner tube because there is no tube to pinch. If you run tubeless, consider taking 3 to 5 psi off the suggested figure and testing for comfort and grip.

What is the Cycling Tyre Pressure Calculator?

Enter total system weight, tyre width, and surface type to compute optimal front and rear tyre pressures for road, gravel, or mountain biking, with a proper front/rear weight split. It runs free in your browser on Gera Tools, with nothing uploaded.

Cycling Tyre Pressure Calculator

Name: Cycling Tyre Pressure Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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The right tyre pressure is one of the cheapest performance upgrades on a bike: too high and you bounce and lose grip, too low and you risk pinch flats and sluggish handling. This calculator sets front and rear targets from your real system weight, tyre width, and surface.

How it works

Pressure scales with the load each tyre carries and inversely with tyre volume. The tool starts from a base pressure tuned to surface type, then adjusts for weight and width and splits front from rear by the seated weight distribution:

rear load  ≈ 60% of system weight
front load ≈ 40% of system weight
base psi   set by surface (road > gravel > mtb)
psi        rises with load-per-mm of tyre width

Wider tyres land at lower pressures for the same rider, and rougher surfaces pull the whole figure down for grip and comfort.

Example and tips

An 82 kg total system on 28 mm road tyres lands near 75 psi front and 80 psi rear; the same rider on 40 mm gravel tyres drops to roughly half that. Start from the suggested numbers, then fine-tune by feel: if the ride is harsh or you lack grip, drop a few psi; if the tyre feels squirmy in corners or you bottom out the rim, add a few. Always stay within the pressure range printed on your tyre sidewall.

Tubeless: run lower than the suggestion

Tubeless tyres can be safely ridden at lower pressures than the equivalent tubed setup because there is no inner tube to pinch between the rim and the road surface. That pinch-flat risk is what historically drove tubed pressures high. Without it, tubeless users typically run 3 to 5 psi below the suggested figure, which improves comfort and grip noticeably — especially on gravel and mountain bikes where traction at low pressure is more important than rolling efficiency. If you run tubeless, treat the tool’s output as a ceiling rather than a target and experiment downward.

Practical tips for checking pressure

Check cold. Tyre pressure rises as the air inside heats during a ride. Always set pressure before you start, never top up a hot tyre to a cold-pressure target.
Measure with a quality gauge. The pressure indicators on most floor pumps are notoriously inaccurate. A dedicated dial or digital gauge that you use consistently is more important than its absolute calibration.
Adjust for weather. Cold air is denser, so tyre pressure drops in winter even without a leak. If you pumped up on a warm day and ride in near-freezing temperatures, expect a few psi of natural loss.
Sidewall range. Every tyre sidewall shows a minimum and maximum pressure. Never exceed the maximum (risk of blowout) or go below the minimum (risk of rim damage on impacts). The calculator’s output will fall within a typical usable range, but your specific tyre’s sidewall rating is the hard limit.

Why the front is lower

A rider seated on a bike places approximately 40% of their weight on the front wheel and 60% on the rear. The front tyre therefore carries less load and needs lower pressure to maintain the same contact patch and deflection as the rear. Running both tyres at the same pressure is a common mistake that over-inflates the front, making steering harsh and reducing grip on corners exactly where you need it most.