COMPONENTS OF A LIGHT ALLOY WHEEL
The rim diameter corresponds to the interior diameter of the tyre in use and is quoted in inch.
The rim with (quoted in inch) indicates the inner distance between the two rim flanges.
Pitch circle diameter / pitch circle:
The pitch circle diameter indicates the diameter of the circle (in mm) of two opposite bolt holes. The pitch circle quotes the number of the holes.
The offset is the distance between the mounting surface and the rim’s centreline.
The hump avoids a slipping of the tyre into the drop centre (e.g. when driving sharp bends)