Backspace / Offset Calculator

Offset / Backspace Converters

Offset (mm)

Wheel Width (in)

Backspace (in) (= A4/25.4 + ((B4+1)/2))

Backspace (in)

Wheel Width (in)

Offset (mm) (= (D4 - (E4+1)/2) * 25.4)

Current Width (in)

Current Offset (mm)

New Width (in)

New Offset (mm)

Wheel will move outbound by

mm

inches

Wheel will move inbound by

mm

inches

Formulas: Outbound mm = (((NewW − CurrW)/2)×25.4) − (NewOff − CurrOff); Inbound mm = (((NewW − CurrW)/2)×25.4) + (NewOff − CurrOff).

Complete the Wheel Position section first (uses Outbound mm).

Distance to outbound location (closest contact point or desired location) (mm)

Spacing needed (mm)

Spacing needed (in)