Wheel Spoke Tension & Dish Calculator

How it works

Bracing angle α = asin(flange offset ÷ spoke length); balance: T_L sin αL = T_R sin αR → T_L ÷ T_R = sin αR ÷ sin αL; drive-side target ≈ 90–95% of rim rating; asymmetric rims add their offset to the drive side's effective flange distance

A rear wheel stays centred because the sideways pulls of the two spoke sets cancel: each side's tension times the sine of its bracing angle must match. The drive-side flange sits close to the centreline to leave room for the cassette, giving those spokes a shallow angle, so they must be pulled far harder — typically 1.5 to 2.5 times the non-drive tension — to balance the wider-angled left spokes. The builder tensions the drive side up to the rim's rating and accepts whatever the geometry dictates on the left; if that falls much below about 50 kgf the left spokes unload under rider weight, nipples back off and the wheel goes out of true. Asymmetric rims, wider hub flanges and mixed lacing all attack the same ratio.

Worked example

With a 33 mm non-drive and 18 mm drive flange offset on a 602 mm ERD rim, the bracing angles are 6.8° and 3.7°, so non-drive tension is only 55% of drive side: 114 kgf on the right (95% of a 120 kgf rim) means 63 kgf on the left — workable but marginal. A 2.5 mm offset rim would lift the left to about 63%.

Frequently asked questions