Tubeless Tire Pressure Calculator
Find the optimal tire pressure for your tubeless setup based on combined rider and bike weight, tire width, wheel position, riding style, and road surface. Use it whenever you switch terrain, tire size, or rider load.
Last updated: September 2026
Formula below · 1 source (Wikipedia) · Updated Sep 2026
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About this calculator
Tubeless tire pressure is a balance between rolling resistance, puncture protection, grip and comfort. This calculator starts from Frank Berto’s 15% tire-drop rule (the pressure at which the tire compresses by about 15% of its width under load), using the widely quoted fit to his chart: P (psi) = 600 × L / W² + 0.75 × W − 25, where L is the load on one wheel in pounds and W is the tire width in mm. The wheel load is riderWeight (kg, rider + bike) × 2.2046 × the wheel share (0.45 front, 0.55 rear). The result is then multiplied by the riding-style factor (0.8 gravel/off-road to 1.1 racing) and the surface factor (1.0 smooth pavement down to 0.85 gravel/dirt), because tubeless setups can run somewhat lower than the 15% drop on rough surfaces. The fit is for 700C tires of about 20-50 mm; for wide MTB tires and for hookless rims, follow the rim and tire maximum and the manufacturer’s chart. Never exceed the lower of the rim and tire pressure limits.
How to use
Example: riderWeight = 85 kg, tireWidth = 40 mm, wheelPosition = 0.55 (rear wheel carries more load), ridingStyle = 1.0 (general riding), roadSurface = 0.9 (mixed surfaces). Step 1 — rear wheel load: 85 × 2.2046 × 0.55 ≈ 103.1 lb. Step 2 — 15% drop pressure: 600 × 103.1 / 40² + 0.75 × 40 − 25 = 38.7 + 30 − 25 = 43.7 psi. Step 3 — style and surface: 43.7 × 1.0 × 0.9 ≈ 39.3 psi. The front wheel (0.45 share, 84.4 lb) of the same setup comes out at 600 × 84.4 / 1600 + 5 = 36.6 × 0.9 ≈ 33.0 psi. The default road setup (75 kg, 28 mm, front) gives about 53 psi.
Frequently asked questions
How much lower can I run tubeless tire pressure compared to a standard clincher?
Tubeless setups typically allow you to run 10–20% lower pressure than an equivalent tubed clincher because there is no inner tube that can be pinched between the rim and an obstacle. For example, a rider who runs 80 psi in a 25 mm tubed tire might safely run 65–70 psi tubeless with the same tire. Lower pressure increases the tire's contact patch, improving grip and absorbing road vibration. However, going too low risks 'burping' sealant out of the bead under hard cornering or impacts, so it is important to find the practical lower limit for your rim-tire combination.
Why does tire width matter so much when calculating the correct tire pressure?
Wider tires have a larger air volume, so they need less pressure to support the same load while maintaining an efficient contact patch shape. Running a narrow tire at the same pressure as a wide one results in an overly hard, small contact patch that transmits road shock and reduces grip. Conversely, running a wide tire at clincher pressures makes it feel wooden and actually increases rolling resistance on rough surfaces. The relationship between width and pressure is roughly inverse — doubling the tire volume allows approximately halving the pressure for equivalent casing tension and load support.
What is the difference in optimal pressure between front and rear tubeless tires?
The rear wheel typically supports 55–60% of the combined rider and bike weight, so it almost always requires higher pressure than the front; in this calculator the rear share is 55% and the front 45%. A common starting rule is to set the rear 10–15% higher than the front; for example, if the front is at 25 psi, the rear might be 27–29 psi. Running equal pressures on both wheels is a frequent beginner mistake that leads to either a squirmy front end (if rear-biased) or an unnecessarily harsh rear feel. Dialling in each wheel separately based on its individual load produces the best balance of grip, comfort, and rolling efficiency.