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.
About this calculator
Tubeless tire pressure is a balance between rolling resistance, puncture protection, and ride comfort. Because there is no inner tube to pinch-flat, tubeless setups can run significantly lower pressures than clinchers, improving grip and damping. The formula used here is: pressure = ((riderWeight × 0.5 + wheelPosition × 2) / tireWidth × 10) + (ridingStyle × 5) + (roadSurface × 3), where riderWeight is total system weight in kg, tireWidth is in mm, and wheelPosition, ridingStyle, and roadSurface are numeric index values that account for load distribution, intended use, and terrain roughness. The 0.5 weighting on rider weight reflects that front and rear tires share the load, while the wheelPosition factor shifts pressure toward the rear (which bears more weight). Wider tires need less pressure to achieve the same contact patch and casing tension.
How to use
Example: riderWeight = 85 kg, tireWidth = 40 mm, wheelPosition = 2 (rear), ridingStyle = 1 (all-road), roadSurface = 1 (mixed tarmac/gravel). Step 1 — core term: (85 × 0.5 + 2 × 2) / 40 × 10 = (42.5 + 4) / 40 × 10 = 46.5 / 40 × 10 = 11.625. Step 2 — style addition: 1 × 5 = 5. Step 3 — surface addition: 1 × 3 = 3. Step 4 — total: 11.625 + 5 + 3 ≈ 19.6 psi. This falls comfortably within the recommended 18–25 psi range for a 40 mm tubeless gravel tire.
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 slightly higher pressure than the front. 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.