It is the question we get asked most: do I need spigot rings with these wheels? The short answer is that it depends on two numbers, and once you know them it takes about ten seconds to work out.
What a spigot ring actually does
The centre bore is the hole in the middle of the wheel. The hub is the raised circular lip on your car that the wheel sits over. On a factory wheel these match exactly, so the wheel is centred by the hub itself. That is what hub centric means.
Aftermarket wheels are made to fit many cars, so the centre bore is usually cut larger than any one hub. A spigot ring is a plastic or alloy collar that fills that gap and centres the wheel properly.
Working out whether you need them
Compare two figures. The wheel's centre bore, listed on every OMI product page. And your car's hub diameter.
Common UK hub sizes: Volkswagen, Skoda and SEAT are 57.1 mm. Audi A3, S3 and TT are 57.1 mm, but the A4 and larger are 66.5 mm. Mercedes is 66.6 mm. Ford is 63.4 mm. BMW is 72.6 mm. Tesla Model 3 and Model Y are 64.1 mm. Range Rover is 72.6 mm.
If the wheel bore is larger than your hub, you need rings to fill the difference. A 66.6 mm wheel on a 57.1 mm Golf hub needs 66.6 to 57.1 rings. If the two match, you do not.
If the wheel bore is smaller than your hub, the wheel will not physically seat. No ring solves that.
What happens if you skip them
The wheel is then centred only by the bolts, which is called lug centric. It can work, but it is far less forgiving. The usual symptom is vibration through the steering at 50 to 70 mph that feels like a balancing problem and never quite goes away no matter how many times the wheels are rebalanced.
Rings cost a few pounds. Chasing a phantom balance fault costs far more.
Do they need replacing?
Plastic rings can be reused but are worth replacing whenever the wheels come off for tyres, since they can distort with heat and age. Alloy rings last longer and are worth it on heavier cars.
The short version
Every OMI product page tells you the centre bore and whether rings are needed for the common fitments. If your car is not listed or you are unsure, send us your registration and we will confirm before you order.