Velopedia Tools

Tire Pressure

Bicycle Tire Pressure Calculator

Estimate independent front and rear pressures from system weight, wheel load, mounted tire width, wheel diameter, surface, casing and air system. The result is a tuning starting point—not a tire or rim pressure rating.

System load

Include riding gear, water, tools and carried cargo.

Units Rider + gear lbBody weight plus worn/carried gear Bike + cargo lbComplete bike, bottles and bike-mounted load

Front wheel load % of total45% is a useful estimate; an actual two-scale measurement is better. Rear load is calculated from the remainder.

Ride & setup

Surface compliance is balanced against impact protection.

Primary surface Air system Rim typeUsed for safety messaging, not to silently cap the result

Tires

Use measured mounted width whenever possible.

Front tire Mounted width mmActual inflated width; marked size is a fallback Wheel size Casing support

Minimum psi Maximum psi

Enter the most restrictive limits published for the tire/rim combination.

Rear tire Mounted width mmActual inflated width; marked size is a fallback Wheel size Casing support

Minimum psi Maximum psi

Enter the most restrictive limits published for the tire/rim combination.

What this calculator is actually doing

Velopedia's model starts with the load carried by each wheel rather than applying one pressure to the whole bike. It represents the mounted tire as a deformable section around the wheel, chooses a surface-specific compliance target, estimates an elliptical contact patch, and derives the air pressure needed to support that wheel load. Small corrections account for casing support and the added pinch/impact margin associated with tubes or inserts.

A ≈ π/4 × contact-width chord × contact-length chordP_start = wheel load ÷ A × casing factor × setup factor

The surface targets and correction factors are Velopedia model choices, not copied manufacturer lookup tables. They are deliberately exposed here so the recommendation is understandable and testable rather than a black-box number.

Why these inputs matter

Wheel load

Pressure follows the load carried by that tire. A two-scale front/rear measurement is better than assuming an even split, especially for cargo bikes and unusual geometry.

Mounted tire width

Actual width captures much of the effect of the tire/rim combination. Wider tires create usable support and compliance at lower pressure, which is why measured width is preferable to the sidewall label.

Surface

Pavement rewards controlled casing support, gravel benefits from additional compliance, and trail/gravity profiles restore impact margin for square-edge hits and aggressive loads.

Casing & air system

Supple casings rely more heavily on air support. Reinforced casings and inserts contribute structure and impact protection, while inner tubes generally require more pinch-flat margin.

Pressure limits are a separate safety question

The calculated value is an operating starting point; it is not a compatibility approval or maximum-pressure specification. Always use the most restrictive minimum and maximum values published for the specific tire and rim. For hookless/TSS systems, confirm that the exact tire and rim combination is approved and follow its stated pressure ceiling. If the calculator's starting point conflicts with a published limit, do not use the calculated value.

Model scope and limitations

This model is intended for conventional pneumatic clincher/tubeless bicycle tires from road through fat-bike widths. It is not intended for tubular, airless or solid tires. It cannot account perfectly for individual tread stiffness, actual casing spring rate, rim-strike shape, suspension setup, riding technique, gauge error, temperature, or manufacturer-specific tire construction. Treat the result as a repeatable baseline, then tune it on the bike in small steps.

Technical cross-checks: Schwalbe tire-pressure guidance · SRAM / Zipp pressure inputs · ENVE pressure guidance · Hutchinson pressure recommendations