ID your Superformance Wheels
Stock 15" wheels have changed since the introduction of the Mark III. Early cars used Trigo wheels. These wheels were replaced by Wheelcraft Alloy Wheels (WAW), which shifted the rear wheels outward 1/4". This new WAW wheel made it difficult to put wider tires on the rear, so the wheels and hubs were changed to bring the tires in 1/2". At this change, the rear hubs became common with the front. The information here will help you identify which wheels you have and help when making wheel or tire upgrades.
The sketch below is a section through the rear wheel and hub. All front wheels have the same hubs and are fully interchangeable
Pictures below show where a quick measurement can help identify which wheels you have
Above 5.25" is typical of cars about 800-1300
Above 4.75" is typical of cars about 1300 to current
A photo of cars up to 800 is not available, but the dimension above should be 5.00"
A Caution on Spinners
All spinners are interchangeable, however the spinner cone is shorter on early WAW spinners and the un-machined portion of the spinner may come in contact with other wheels before the spinner conical comes in contact with the wheel conical. If you find this condition, you must change to late WAW spinners.
Aftermarket Wheels and Spinners
Aftermarket wheels and spinners CC has seen employ the same critical dimensions late WAW, however, if purchasing aftermarket wheels, all critical dimensions listed here should be verified