Short answer: if the wheel's centre bore is larger than your car's hub, yes, you need spigot rings. Without them the wheel is centred by the bolts instead of the hub, and you get a vibration at speed that no amount of balancing will ever cure.
This is the single most common reason a brand new set of wheels feels wrong, and the fix costs a few pounds.
What centre bore actually is
Look at the back of any alloy wheel. There is a machined hole in the middle, separate from the bolt holes. That is the centre bore.
Your car has a matching raised lip on the hub. When the two meet, the wheel sits on that lip and is held dead centre by metal. The bolts then clamp it in place.
That is the important distinction, and most people have it backwards:
- The hub centres the wheel. That is its job
- The bolts clamp the wheel. That is their job
Bolts are not designed to centre anything. They are designed to squeeze the wheel against the hub face. Ask them to do the centring as well and they will get it slightly wrong, every time.
Why aftermarket wheels have oversized bores
A manufacturer making a wheel for one car machines the bore to that car's hub exactly. That is a hub-centric wheel, and it needs nothing extra.
An aftermarket manufacturer wants one wheel to fit many cars. So they machine the bore oversized, usually 72.6mm or 73.1mm, big enough to clear almost any hub. Then they supply plastic or alloy rings that take up the gap for your specific car.
That is not a shortcut or a quality problem. It is how the whole industry works. The mistake is throwing the rings away or not realising you needed them.
The two numbers you need
| Number | Where to find it |
|---|---|
| Your car's hub diameter | Measure the raised lip on the hub with a vernier, or look up your car |
| The wheel's centre bore | Listed on every product page of ours, often stamped on the back of the wheel |
Then it is simple arithmetic:
- Wheel bore larger than hub? You need rings. Ring size is written as wheel bore to hub bore, for example 73.1 to 57.1
- Wheel bore the same as hub? Hub-centric already. Nothing needed
- Wheel bore smaller than hub? The wheel will not go on. Do not force it, do not machine it. Wrong wheel
Common hub sizes
| Make | Typical hub bore |
|---|---|
| Audi, VW, SEAT, Skoda (5x112) | 57.1mm |
| Mercedes (5x112) | 66.6mm |
| BMW E and F chassis (5x120) | 72.5mm |
| BMW G chassis (5x112) | 66.5mm |
| Ford (5x108) | 63.4mm |
| Range Rover, Jaguar (5x120) | 72.5mm |
| Porsche (5x130) | 71.6mm |
Note Audi and Mercedes. Both 5x112, completely different hub bores. A wheel that physically bolts to both needs different rings for each, and that catches people out constantly.
How to tell this is your problem
A centre bore vibration has a signature:
- It appears at a specific speed range, often 45 to 65mph, and sometimes fades above it
- You feel it through the steering wheel if it is the front, through the seat if it is the rear
- Rebalancing does not fix it. This is the giveaway
- It started the day the new wheels went on
If a tyre shop has balanced them twice and it is still there, stop paying for balancing. Check the bore.
Plastic or alloy rings?
Both work. The ring is not load bearing in the way people assume, it is a locator, so plastic is perfectly adequate and is what most wheel manufacturers supply.
Alloy rings last longer and cope better with heat near the brakes. They can corrode onto the hub over years, which makes the wheel a pig to remove, so a smear of copper grease on fitting is worth the thirty seconds.
Either way, rings stay with the car, not the wheel. If you swap back to winter wheels, the rings come off with the summer set.
Where this matters most
Heavier cars and bigger wheels. A 22 inch wheel on a Range Rover carries far more mass further from the hub than a 17 inch wheel on a Polo. The vibration is worse and the stress on the bolts is higher.
Our 22x9.5" Autobiography Turbine Style wheels are machined to 72.5mm for the Range Rover hub, so no rings are needed. That is deliberate. We list the centre bore on every product page precisely so you can check before you order.
In stock, with the bore listed
- 18x8" Concept TTRS Twist Style, Gunmetal — from £140
- 18x8" VRS Style, Gunmetal — from £140
- 20x9" TTRS Rotor Style, Satin Gunmetal — from £160
- 20x9" Golf R Estoril Style, Gloss Black — from £160
- 17x7.5" VW Clubsport Style, Black Machined — from £132.50
Spacers have the same problem, doubled
A spacer sits between hub and wheel, so it has two bores to get right: the inner one locating on your hub, and the outer one the wheel locates on. Both must be correct or you have reintroduced the exact problem rings exist to solve.
Every spacer in our spacer range is hub-centric on both faces and machined for the specific car it is listed against. We go into the sizing in our wheel spacer guide.
Common questions
Do I need spigot rings for my alloy wheels?
Only if the wheel's centre bore is larger than your car's hub diameter. Many aftermarket wheels are machined oversized to fit multiple cars, so rings are usually needed. Wheels machined specifically for your car are hub-centric and need nothing.
What happens if I do not use spigot rings?
The wheel is centred by the bolts instead of the hub, so it sits very slightly off centre. The result is a vibration at speed that rebalancing will not fix, and additional stress on the wheel bolts over time.
Are plastic spigot rings safe?
Yes. The ring locates the wheel, it does not carry the vehicle's weight, which is taken by the clamping force between wheel and hub face. Plastic rings are what most wheel manufacturers supply as standard.
Why do my new alloy wheels vibrate even after balancing?
Almost always the centre bore. If the wheel is not located on the hub lip, no amount of balancing will centre it. Check the wheel bore against your hub diameter before paying for another balance.
What size spigot rings do I need?
They are described as wheel bore to hub bore. A 73.1mm wheel on a 57.1mm Audi hub needs 73.1 to 57.1 rings. Both numbers are on our product pages.
Can I fit a wheel whose bore is smaller than my hub?
No. The wheel will not seat on the hub. Do not force it and do not have the bore machined out, because that removes material from the strongest part of the wheel.
Tell us your car and we will tell you the numbers. Send your make and model and we will confirm the hub bore, stud pattern and offset, and say whether rings are needed, before you order. sales@omiwheels.com or WhatsApp +44 7753 828059.