rim offset

Basically the offset says where the wheel centre is relative to the hub. If you've got this months retro and look at the Broadsport jag, it looks like it's got shallow offset wheels on the front and deep offset ones on the back. If you've got last months retro (I think), it explains offsets. The offset matters because having the wrong offset will alter the track of the car, and thus the suspension geometry, as well as leaving you with wheels stuck out of arches or disappearing underneath the car, fouling problems etc.

A rather bad pair of ASCII diagrams (viewing a cross section of the wheel, # represents hub). Should work with a fixed width font.

___ #| deep offset ¯¯¯ ___ #| shallow offset ¯¯¯