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Enter your values and press Calculate.
Enter your weight, your bike's weight, your measured tyre width, your bike discipline, whether the tyres are clincher (tubed) or tubeless, and the terrain you will ride. The calculator totals rider and bike into system weight, works out a base front pressure from the 45 percent front load share scaled by tyre width, then adds a 5 PSI rear bias. It multiplies by 1.00 for smooth tarmac, 0.95 for rough pavement, or 0.90 for gravel and trails, subtracts 5 PSI for tubeless setups, and finally clamps the pair inside safe bounds for the chosen discipline. You get front and rear pressure in PSI and in bar. Use the numbers as a starting point and fine-tune by feel within your tyre and rim limits.
Tyre pressure is one of the cheapest performance upgrades in cycling. On any bicycle, too high a pressure bounces over bumps instead of deforming around them, which increases rolling resistance on real roads, shrinks the contact patch, and rattles the rider. Too low and the tyre squirms in corners, feels sluggish, and risks pinch flats where the tube or rim strikes through to the rim. The right pressure keeps the casing at its intended shape under load, so you get maximum grip, minimum rolling resistance, and fewer punctures. These are estimates for reference, not professional advice: always confirm against your tyre and rim maker's limits.
The calculator follows the physics of tyre drop, the small casing deformation that supports the load. It uses total system weight (rider plus bike), splits it 45 percent front and 55 percent rear, and scales the result inversely with tyre width: a wider casing holds more air volume, so it needs less pressure to carry the same load. The rear gets a fixed 5 PSI bonus on top, because a percentage-based gap would over-inflate narrow tyres and under-inflate wide ones. The model then applies a terrain factor and a tubeless offset, and clamps the result inside safe bounds for the bike discipline you selected.
On most bikes the rear wheel carries more of the combined rider and bike weight, so equal front and rear pressure is a common mistake. With equal pressure the front is over-inflated for its load (harsh ride, less cornering grip) while the rear is under-inflated (more rolling resistance, higher pinch flat risk). This calculator therefore returns two separate numbers, with the rear running about 5 PSI higher than the front. That matches the 5 to 7 PSI rear bias used across modern pressure charts, which works out to roughly 3 to 14 percent depending on the absolute pressure.
A clincher (tubed) tyre and a tubeless tyre of the same width do not want the same pressure. Without an inner tube there is no tube-to-casing friction, and the supple casing conforms better to road imperfections, so tubeless setups roll best at lower pressures. The calculator subtracts 5 PSI when you select tubeless. Do not go too low: below about 50 PSI on narrow 25 to 28 mm tubeless tyres the sealant can burp out at the bead under hard cornering, so fine-tune by feel and stay above your tyre's stated minimum.
Smooth tarmac lets you run the full calculated pressure. On rough pavement the calculator applies a 5 percent reduction so the tyre absorbs vibration instead of transmitting it to your hands and back. For gravel, light trails and cobbles it applies a 10 percent reduction for extra grip and comfort. For the cobbled classics professionals have been known to drop to 55 to 65 PSI on 28 to 30 mm tyres, which shows how much lower pressure can go when the surface gets violent. The selector uses percentage factors rather than fixed PSI subtractions so the adjustment stays sensible for low-pressure mountain bike setups too.
Take a 75 kg rider with an 8 kg road bike on 28 mm clincher tyres on smooth pavement. System weight is 83 kg. The base front pressure is (83 × 0.45 × 2.25) / (28 / 25) = 75.0 PSI, and the rear is 75.0 + 5 = 80.0 PSI. In bar that is 75 / 14.5 = 5.2 bar front and 80 / 14.5 = 5.5 bar rear. Now change the setup to 38 mm tubeless tyres on a gravel bike on rough gravel: the same rider and a 12 kg bike give a system weight of 97 kg, a base front of 64.6 PSI, a gravel factor of 0.90 (58.2 PSI), and a tubeless offset of minus 5 PSI, for a final 53.2 PSI front and 57.7 PSI rear. Same rider, very different tyres, and the model tracks the change automatically. The PSI to bar conversion (divide PSI by 14.5) is applied to every result, so you get both units without doing the maths yourself.
Use these as rough starting ranges, then let the calculator give you a personalised pair of numbers.
| Bike type | Typical tyre width | Pressure range | |---|---|---| | Road bike | 23-28 mm | 80-120 PSI | | Gravel bike | 30-45 mm | 40-60 PSI | | Hybrid / commuter | 32-50 mm | 50-70 PSI | | Mountain bike (trail) | 2.0-2.6 in | 18-35 PSI |
Heavier riders sit at the top of each range and lighter riders at the bottom. Wider tyres always want lower pressure than narrower ones for the same system weight, which is why the calculator scales pressure by the inverse of tyre width.
The calculator clamps its output so it never suggests a pressure outside safe bounds for the discipline you picked: 40 to 130 PSI for road, 25 to 80 PSI for gravel, 15 to 45 PSI for mountain, and 40 to 100 PSI for hybrid. One extra rule the tool does not override: if you run hookless (straight sidewall) rims, never exceed 72.5 PSI (5 bar) regardless of what the tyre sidewall allows, per ETRTO guidelines. Exceeding the rim or tyre maximum can unseat the tyre, so treat the lower of the two limits as absolute and check pressure with a gauge before every ride, not with your thumb.
As a starting point, a 75kg rider on 28mm clincher tyres wants about 75 PSI front and 80 PSI rear on smooth pavement. Tubeless tyres of the same width run roughly 5 PSI lower. Heavier riders go higher, lighter riders go lower, and wider tyres need lower pressure than narrower ones. Enter your exact numbers above for a personalised front and rear recommendation.
No. The rear wheel carries more of the combined rider and bike weight, so it should run about 5 PSI higher than the front (roughly 3 to 14 percent depending on the absolute pressure). Running identical pressure means the front is over-inflated for its load, giving a harsh ride and less cornering grip, while the rear is under-inflated, adding rolling resistance and pinch flat risk.
Heavier riders need higher pressure to prevent excessive tyre deformation under load. As a rough guide, the base model scales pressure almost linearly with total system weight (rider plus bike), so adding 10 kg of system weight adds roughly 7 to 9 PSI at typical road widths. That is why the calculator asks for rider weight and bike weight rather than rider weight alone.
Yes. Without an inner tube there is no tube-to-casing friction and the supple casing conforms better to the road, so tubeless tyres roll best about 5 PSI lower than clinchers of the same width. This calculator subtracts 5 PSI automatically when you select tubeless. Avoid going below about 50 PSI on narrow 25 to 28 mm tubeless tyres, where the sealant can burp out at the bead.
Wider tyres need lower pressure for the same rider weight because the larger air volume carries the load with less casing stress. A 28 mm tyre at 75 PSI deforms about as much as a 23 mm tyre at 100 PSI. Modern testing shows wider tyres at lower pressure are actually faster on real roads, because the energy saved by absorbing vibrations outweighs any aerodynamic penalty. Enter your measured tyre width above for the correct scaling.
Most road tyres are rated for 100 to 130 PSI maximum (check the sidewall), but hookless rims common on modern carbon wheels are limited to 72.5 PSI (5 bar) per ETRTO guidelines no matter what the tyre is rated for. Treat the lower of the tyre and rim limits as absolute, and note that maximum pressure is rarely optimal: most riders go fastest at 60 to 80 percent of maximum.
Check before every ride. Tyres lose air through the casing and valve over time, and even a few PSI below your target changes the handling. A floor pump with a built-in gauge is the reliable tool; squeezing the tyre with your thumb is not precise enough to detect small drops.
Air pressure rises with temperature and falls with cold, roughly 1 PSI for every 5 C change. That means a tyre set at 80 PSI in a cool garage can read several PSI higher after an hour in the sun. Always set pressure at the temperature you will be riding in, and re-check when the weather swings.
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