Whats offset?
Imagine your wheel as a round two-layer cake, with the street side of the wheel corresponding to the top surface of the cake. If the layers are exactly the same height, the center layer of frosting on the cake would be at the centerline of the wheel. The offset describes how far from this centerline the plane at which vehicle hub and wheel touch each other, with positive toward the street side. Naturally, if the offset is non-zero, there is an uneven load on the wheel bearing, which was designed into the wheel bearing. Choosing a correct offset is very important, as the bearings on the car are designed for a specific load. The rule of thumb is that an aftermarket wheel offset shouldn’t more than 20% of the stock value, which for 3rd Gen RX7s gives a range of 40mm to 60mm or so. (Incidentally, the tire width does make some difference in choosing a correct offset. If we put significantly wider rubber on our cars, ideally, we would want to add in a little additional offset (in proportion
