How to choose
What a wheel fitting kit is
Aftermarket alloy wheels are often made so that one and the same wheel fits several cars. In that case the fixings are not included in the wheel box and are bought separately. OZ Racing calls this the Kit-System in its fitting instructions: hub-centric rings and wheel bolts chosen for the specific car. This section has OZ Racing, Alcar and Alutec fixings intended for wheels of these brands. OZ Racing kits with a ring are made up for one wheel - five fixings and one ring - so a car needs four. Alcar and Alutec bolts come in larger packs without rings.
Why not just any bolts
For each car the wheel manufacturer specifies which bolts or nuts to use: seat, thread and length. For example, the Alcar wheel certificate for one Volvo model lists conical 60° bolts, M14x1.5, with a 34 mm thread length. The length depends on how thick the wheel is at the mounting point, but the seat has to match the hole in the wheel. Alcar's instructions warn that the wrong combination of parts (a different type, shape or length) can work loose, and the wheel can come off. OZ allows the car's original bolts only where this is specifically stated. For some cars it is, and then no kit is needed.
How to choose
- Wheel brand. A kit is meant for its own manufacturer's wheels, and you will find the right fixings for your car in the wheel manufacturer's application list or certificate.
- Thread and type. The thread, and whether the car uses bolts or nuts, is set by the car. You can read it off the old bolt or find it out from the carmaker.
- Centre bore (DIA). The outer size of the hub-centric ring (often also called a centring ring) has to match the wheel's centre bore, and the inner size the car's hub.
- Wrench size. OZ recommends checking whether the wrench supplied with the car fits the new bolts. If it does not, carry the right one with you.
Original bolts, locking wheel bolts and tightening
A kit replaces the car's bolts for these wheels only. Keep the original bolts for the original wheels and the spare: both OZ and Alcar state that the spare wheel is fitted with the car's original bolts, so a set of them has to stay in the car. Locking wheel bolts are not included in the kits and are in a separate section, "Locking wheel bolts". When choosing them, the thread and seat must be the same as on the kit bolts.
The tightening torque is set by the carmaker, and for aftermarket wheels it is also given in the wheel certificate. Tighten with a torque wrench, in a cross pattern. Do not oil the threads: both the OZ and Alcar instructions forbid it, and it is printed on the OZ kit bag. Alcar recommends checking the bolts after 50-100 km and retightening them if needed.