Tire Pressure Calculator
Enter your system weight, measured tire width and the surface you ride, and get front and rear pressures in psi and bar — with the weight split of your riding position, casing and rim-type corrections, and hookless-safe caps built in.
Your setup
Tire system
Rim bead
Front
59.5 psi
4.10 bar
Rear
64.5 psi
4.45 bar
System weight
80.5 kg
rider + bike
Front / rear split
48% / 52%
Road (hoods/drops)
Surface
Worn pavement
Tubeless
Start here, then fine-tune ±2 psi by feel: chattery or skittish over texture → let a little out; wallowy or squirmy in corners → add a little. Never exceed the maximum printed on your tire or rim.
How to use it
- 1Weigh yourself in kit, and your bike as it rolls — bottles, cages, saddle bag, repair kit.
- 2Measure your tire's real width with calipers at pressure; on wide rims it's often 2–3 mm over the label.
- 3Pick the surface you'll actually ride, not the best road on the route — rough sections cost more than smooth ones save.
- 4Set your tire system (tubeless, latex or butyl tube, tubular) and rim bead type (hooked or hookless).
- 5Choose your riding position to set the front/rear weight split, or dial a custom split if you know yours.
- 6Read the front and rear pressures, inflate, then fine-tune ±2 psi by feel over a few rides.
Lower pressure is usually faster
The old logic said pump it hard: less tire squish, less rolling resistance. Lab rollers agreed — real roads don't. Above the optimum, extra pressure stops flattening the tire and starts bouncing the whole bike and rider off every bit of texture. Those vibrations are energy leaving your forward motion (and fatiguing your muscles), a loss that grows faster than the casing savings. The optimum is the breakeven point: enough pressure that the casing doesn't wallow, little enough that the tire absorbs the surface instead of ricocheting off it. Past it, more air makes you slower — it only feels fast.
Load per wheel, not just rider weight
Pressure exists to carry weight, so the right number depends on how much weight each wheel carries. Total system weight is you plus bike plus bottles and bags — and the split between wheels comes from your riding position. On the hoods roughly half the load sits on the rear wheel and slightly less up front; in a TT tuck the front is loaded harder than the rear; on a MTB the rear dominates. That's why this calculator gives two numbers, and why your front tire almost always wants a few psi less than the rear.
Width, casing and surface set the curve
The same load on a wider tire needs far less pressure — air volume rises with the square of width, so a 32 mm tire carries the load of a 25 at two-thirds the pressure. Measured width matters more than the label: modern wide rims blow a nominal 28 out past 30 mm. Casing type shifts the number too (tubeless can safely run a little lower; stiff butyl tubes want a touch more), and surface is the biggest lever of all — cobbles and gravel reward dropping well below the smooth-road number.
Hookless rims have a hard ceiling
Hookless (straight-side) rims rely on tire fit rather than a bead hook, and ETRTO caps them at 72.5 psi (5 bar) regardless of what the tire says. If your load and width put the optimum above that, this calculator clamps the recommendation and tells you — the honest fix is a wider tire, which brings the optimum back under the ceiling and rolls just as fast.
How the math works
The base pressure is a power-law fit through the classic 15% tire-drop data (Frank Berto's load-deflection charts), recalibrated against current road, gravel and MTB practice: pressure = 333 × wheel-load(kg) ÷ width(mm)^1.5785, computed separately per wheel from your position's weight split. Surface (track +5% down to chunky gravel −35%), casing (tubeless −5%, butyl +2%, tubular −2%), wheel diameter (650b +2%, 26″ +4%) and speed (±2%) scale that base. Safety rails are applied last: hookless rims cap at the ETRTO 72.5 psi maximum, recommendations never drop below 10 psi, and the tool warns on pinch-flat risk (tubes below 30 psi on rough surfaces) and above 100 psi. It's a starting point calibrated to the same anchors the wider industry uses — your perfect number is within a couple of psi of it, found by feel.
Built and reviewed by the PaceBeats coaching-engine team. Every calculator runs the same sports-science math that powers the app's adaptive plans.
Common questions
Should my front and rear tire pressure be different?
Yes. Your wheels don't carry equal weight — on a road bike roughly 48% of the system weight sits on the front wheel and 52% on the rear, and in a TT position the front carries more than the rear. Since optimal pressure scales with load, the lighter-loaded wheel wants proportionally less air. Running both tires at the same pressure means one of them is wrong: usually an over-inflated front that chatters and washes out in corners.
Is higher tire pressure faster?
Only up to the optimum, and modern optima are lower than most riders think. On real surfaces, pressure above the breakeven point makes the bike vibrate instead of roll — and vibration is drag. Testing consistently shows a properly-pressured wide tire matches or beats a rock-hard narrow one everywhere except a velodrome. If your tires never leave you buzzing after a chipseal section, you're probably close; if they do, let air out.
What pressure should I run tubeless?
About 5% less than the equivalent tubed setup, and this calculator builds that in when you select tubeless. With no tube to pinch, the practical floor is set by rim strikes and casing squirm rather than snakebites, so tubeless lets you exploit the low end of the range — especially on gravel, where the grip and comfort gains are large. Stay under your rim's limit (72.5 psi max on hookless) and add sealant-friendly margin before big rock gardens.
Does tire width change the pressure I should run?
Dramatically — width is the strongest variable in the whole model. Air volume grows with roughly the square of width, so each step up in size carries the same load at markedly lower pressure: a 70 kg rider who needs ~84 psi on 25 mm tires needs only ~57 psi on 32s and ~35 psi on 40 mm gravel tires. Use the measured width, not the printed one; a '28 mm' tire on a modern 25 mm-internal rim often measures 30+ and should be pressured as such.
Next step
Turn these numbers into an adaptive plan.
PaceBeats uses this exact math — and your training history — to build and adapt your training week after week, in your sport or all four.