Are wheel spacers safe?

Hub-centric wheel spacers that are properly torqued with extended studs or bolts are generally safe. However, they must be high quality (forged aluminium), correctly sized, and regularly checked for tightness. Many motorsport organisations ban spacers over 15mm.

Do wheel spacers affect handling?

Spacers increase the track width, which can improve cornering stability but also increases the load on wheel bearings. Large spacers change the scrub radius and can make the steering feel different. Keep spacers as thin as possible.

Will spacers affect my MOT?

Wheel spacers are not specifically mentioned in the MOT test, but if they cause the tyres to protrude beyond the bodywork or interfere with steering/suspension, the car will fail. The wheels and tyres must also be securely attached.

Do I need to tell my insurer about wheel spacers?

Yes. Wheel spacers are a vehicle modification and must be declared to your insurance company. Failure to disclose could invalidate your policy in the event of a claim. Some insurers charge a small additional premium, while others may refuse to cover the modification.

What thickness wheel spacers should I use?

Use the minimum thickness needed to achieve your desired look or clearance. 5-10mm spacers give a subtle improvement. 15-20mm gives a noticeable stance change but may require longer wheel bolts or studs. Over 25mm is generally not recommended for road use.

CarCalcs

Wheel Spacer Calculator

Calculate what thickness wheel spacers you need for your desired offset.

Current Offset (ET)

Your wheel's current ET value

Desired Offset (ET)

The ET you want to achieve

How We Calculate This

Wheel spacer thickness equals the difference between your current offset and your desired (lower) offset. A spacer pushes the wheel outward by its thickness.

Formula

Spacer thickness = Current offset - Desired offset
Track width increase = Spacer thickness x 2 (both sides)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Actual figures may vary based on driving conditions, vehicle specifications, and other factors.