Wheel spacers sit between the hub and the wheel and push the wheel outward. People fit them for two reasons: to clear a big brake caliper, or to bring the wheel face flush with the arch. Both are legitimate. The problem is that most of the advice online skips the three numbers that decide whether a spacer fits at all.
This guide covers those numbers, the safety question, and the UK legal position.
What size wheel spacer do I need?
There is no universal answer, because the size you need depends on your current offset and how much room you have. As a working rule:
- 5mm to 12mm – caliper clearance after a brake upgrade, or a very small stance correction. Usually fits under standard arches with no rubbing.
- 15mm to 20mm – the common choice. Noticeably fills the arch without needing arch work on most cars.
- 25mm and above – serious stance, or a wide-track conversion. Expect to check arch clearance on full lock and over bumps.
- 40mm to 50mm – almost always pickups and 4x4s, where the track is being widened deliberately. Our 50mm X-Class spacers are a typical example.
Spacers above roughly 20mm need longer bolts or a bolt-on spacer with its own studs, because the original bolts will no longer have enough thread engagement. That is not optional.
The three numbers you must match
A spacer has to match your car on all three of these. Get one wrong and it will not mount.
| Spec | What it means | Example |
|---|---|---|
| PCD / bolt pattern | Number of bolts and the circle they sit on, in mm | 5×112, 5×108, 6×114.3 |
| Centre bore | Diameter of the centre hole, in mm | 66.5mm, 63.3mm |
| Thread pitch | Bolt or stud thread size | M14×1.25, M12×1.5 |
A BMW on 5×112 needs 66.5mm bore and M14×1.25. A Ford Focus on 5×108 needs 63.3mm bore and M12×1.5. They are not interchangeable even though both are five-bolt wheels. If you are unsure of your bolt pattern, our 5x112 guide explains how to measure it.
What does hub-centric mean, and does it matter?
Hub-centric means the spacer has a machined lip that locates on your car's hub, and a matching lip on the outer face that your wheel locates on. The spacer carries the wheel's weight on that lip, exactly as the hub normally would.
The alternative, lug-centric, relies on the bolts alone to centre and support the wheel. On a road car this is the wrong choice. It is the single most common cause of vibration after fitting spacers, and in the worst case it loads the bolts in shear rather than tension.
Buy hub-centric spacers. Every spacer we sell is hub-centric and machined for a specific hub diameter, which is why they are listed per car rather than as a generic size. The same principle applies to wheels, which is covered in our guide to spigot rings.
Are wheel spacers legal in the UK?
Yes. There is no UK law prohibiting wheel spacers on a road car, and there is no specific MOT test item for them.
Two caveats that do matter:
- The tyre must not protrude beyond the arch. Construction and Use regulations require wheels and tyres to be covered by the bodywork. Spacers that push the tyre proud of the wing can fail an MOT under tyre and bodywork checks, and can attract a Construction and Use offence.
- Tell your insurer. Spacers are a modification. Not declaring them gives an insurer grounds to reduce or refuse a claim. It is normally a small or nil premium change; not declaring it is the expensive option.
Fitted properly, with correct bolt engagement and the tyre inside the arch, spacers are no more dangerous than a different offset wheel. The failures you read about are almost always lug-centric spacers, original bolts used with a thick spacer, or bolts that were never re-torqued.
Fitting: the part people skip
- Clean the hub face. Rust or old grease under a spacer causes runout and vibration.
- Torque to the manufacturer's figure with a torque wrench, not an impact gun.
- Re-torque after 50 to 100 miles. This is the step that gets missed and it is the one that matters most.
- Check arch clearance on full lock, and with the car loaded.
Popular fitments we stock
All sold in pairs, hub-centric, with the bolt pattern and bore in the product title so you can check at a glance:
- BMW 3 Series G20 / G80 M3, 20mm – 5×112, M14×1.25, 66.5mm
- BMW M3 G80 and M4 G82, 20mm – 5×112, M14×1.25, 66.5mm
- Ford Focus MK3 ST250 and RS, 15mm – 5×108, M12×1.5, 63.3mm
- Ford Focus MK4 ST, 15mm – 5×108, M12×1.5, 63.3mm
- BMW M5 F90, 20mm – 5×112, M14×1.25, 66.5mm
To find spacers for your own car, use the car picker on our performance parts page — pick your make and model and it shows only parts that fit it. You can also browse the full wheel accessories range.
Still not sure?
Send us your registration and what you are trying to achieve — caliper clearance or arch fill — and we will tell you the size and spec you need. If a spacer is the wrong answer for your car, we will say so.