Offset Measurement

The offset of a wheel is the distance from the centre line of the wheel to the mounting face of the nave plate.

The easiest ways to calculate the offset of a wheel varies, depending on whether it is a single or twin type wheel.

Single Wheel

Using a flat object across the front edge of the rim, measure down to the front of the nave plate. (see picture) The offset can calculated using this measurement. The exact same measurement can be taken from the back edge of the wheel to the mounting face. It is also useful to measure the thickness of the nave plate. It is always advisable to take these measurements without a tyre fitted to the wheel, as it can be difficult to get accurate results.

Twin Wheel

When a wheel is fitted in twin format, the term HDS (Half Dual Spacing) is used. This is the measurement from the centre line of the rim to the outer face of the nave plate. (Offset + nave thickness).

With the wheel turned on its side, use a flat object placed across the front face of the dish nave and measure down to the floor. This will give a measurement of the overall height, from which we can calculate the Half Dual Spacing (HDS). Again its easier to take this measurement with no tyre fitted to the rim for greater accuracy.