Dishwell Cycle Works

Calculator

Tyre pressure

kg
kg
mm
psi

Rear

83psi

5.7 bar

Front

53psi

3.6 bar

Working

How it is worked out

A starting point, not an answer. Ride it, then go 5 psi either way.

  1. Load on each wheel. Rider plus bike, 60 % on the rear and 40 % on the front, in pounds.
  2. Pressure for 15 % tyre drop. Frank Berto’s measurements, fitted as psi = 153.6 × load ÷ width1.5785 − 7.17.
  3. Surface. Worn road × 0.93, gravel × 0.85, mixed off-road × 0.78.
  4. Tubeless. × 0.92, because there is no tube to pinch.
  5. Limits. Never above the maximum printed on the tyre, and never above 72 psi (5 bar) on a hookless rim.

Check the limits printed on your tyre and rim. The lower of the two wins.

Next

Does the tyre fit the rim?

A 28 mm tyre on a 25 mm rim sits too square. The tyre and rim checker gives the range for your rim.

Tyre and rim fit

Black and white bicycle wheel with the shadow of its spokes on a wall