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Free Tool

TYRE PRESSURE CALCULATOR

Science-based pressure recommendations based on your weight, tyre width, rim width, setup type, and road surface.

Check your wheel manufacturer specs. Most modern road wheels are 19-21mm.

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Quick answer

Enter rider and bike weight, tyre and internal rim width, road surface, and tube type. The calculator returns front and rear PSI targets following SILCA-style impedance-loss optimisation — the same logic the WorldTour use to set up their tyres.

WHAT IT DOES

The right tyre pressure isn't "the maximum on the sidewall" — that's almost always too high. Lower pressures roll faster on real roads because they reduce impedance losses (the energy spent vibrating the rider, not just the tyre). This calculator gives you front and rear targets for your specific setup and surface.

WHO IT'S FOR

  • →Anyone running modern wide tyres (28mm+) on hookless or wide rims
  • →Riders who still pump to 100+ psi out of habit
  • →Gravel and all-road cyclists juggling road and rough surfaces
  • →Tubeless converts who want to confirm safe minimums

HOW IT WORKS

Optimal pressure scales with system weight (rider + bike + kit), tyre volume (width × internal rim width), and surface roughness. We model this off SILCA-style impedance-loss research — pressure too high causes the tyre to bounce instead of rolling, costing watts. Front pressure runs ~5 PSI lower than rear because the front carries less weight.

  1. 01

    Weigh yourself in kit

    Add your weight in cycling kit, the bike, plus bottles and any luggage. Most riders forget to add 1-2 kg of kit and bottles.

  2. 02

    Measure rim width, not stated tyre width

    Internal rim width is the number that matters. Measure with calipers or check the manufacturer spec. Modern road rims are 19-25 mm internal.

  3. 03

    Pick the surface

    Smooth tarmac, rough chip-seal, or gravel/cobbles. Each surface shifts the optimal pressure down by several PSI.

  4. 04

    Set front and rear separately

    The calculator returns different front and rear values. Set them with a digital pressure gauge — most floor pumps are wrong by 5-10 PSI.

EXAMPLE CALCULATIONS

75kg rider, 28mm tubeless, 21mm rim, smooth tarmac

  • · Total weight: 84kg
  • · Tyre: 28mm
  • · Rim: 21mm
  • · Surface: smooth
  • · Tube: tubeless

Front: 65 PSI. Rear: 70 PSI.

85kg rider, 38mm gravel tubeless, 24mm rim, gravel surface

  • · Total weight: 95kg
  • · Tyre: 38mm
  • · Rim: 24mm
  • · Surface: gravel
  • · Tube: tubeless

Front: 32 PSI. Rear: 36 PSI.

LIMITATIONS

The calculator can't see your specific tyre casing (some tyres have noticeably different impedance curves), your rim's actual mounted tyre width (which is often 1-2 mm wider than stated), or your tubeless sealant volume. Use the output as a starting point; adjust ±5 PSI based on how the bike feels on your local roads.

When to see a coach

If you're tracking watts on a known segment and the difference between two pressures is in the noise — it probably is. Tyre-pressure optimisation is worth 5-15 watts on rough roads but isn't going to win you a race. Get the basics right, then move on.

FREQUENTLY ASKED QUESTIONS

What tyre pressure should I run on a road bike?+

For a 70kg rider on 28mm tubeless tyres with 21mm internal rims on smooth tarmac, around 65-70 PSI front, 70-75 PSI rear is fast. Add 5-10 PSI per 10kg above 70kg. Subtract 5-10 PSI for rough roads. The sidewall maximum is a safety limit, not a target — it's almost always too high.

Why do lower tyre pressures roll faster?+

On real roads, energy is lost two ways — hysteresis (tyre deformation) and impedance (rider/bike vibration). Higher pressure reduces hysteresis but increases impedance, because the tyre bounces over bumps instead of absorbing them. Below the optimum, hysteresis dominates and you get slower; above, impedance dominates. SILCA's research found the optimum is usually well below the sidewall max.

How much lower should front pressure be than rear?+

Around 5 PSI lower on a road bike, because the front wheel carries roughly 40% of system weight versus 60% on the rear. On gravel or all-road, the gap can grow to 4-6 PSI. Running equal pressure makes the front feel harsh and the rear feel soft.

Are tubeless tyres faster than tubes?+

Yes — typically 5-15 watts faster at the same pressure due to lower hysteresis losses, plus tubeless lets you safely run lower pressures (no pinch flat risk), unlocking more impedance gains. The trade-off is setup hassle and sealant maintenance.

Is the maximum sidewall pressure safe?+

Yes, it's a safety limit. But it's not the target. The sidewall max exists for legal/insurance reasons — running near it on a wide modern tyre with a wide rim almost always rolls slower and definitely feels worse. Treat the calculator's number as the target and the sidewall as a never-exceed ceiling.

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