Help Centre
Measure the Rim, Not the Spokes
Last updated: September 12, 2026
Diameter is a specification, so it should be measured like one. The figure that matters is the rim's outer diameter across the centre, taken with the wheel centred.
For reference, most modern cars measure between 360 mm and 380 mm.
The Measurement
Three readings are enough to be confident. Take them at three angles and use the largest.
- Centre the wheel and straighten the front wheels.
- Lay the tape across the centre hub and read outer edge to outer edge.
- Repeat at roughly 60 and 120 degrees.
- Record the largest figure to the nearest millimetre.
The largest reading is the true diameter; a smaller one usually means the tape was not across the centre.
Reference Ranges
Sizes cluster. Compact sports cars sit near 340–350 mm. Hatchbacks near 360 mm. Most modern saloons fall between 365 and 370 mm, larger saloons and SUVs near 380 mm, and vans or trucks at 390–400 mm.
| Range | Inches | Vehicle class |
|---|---|---|
| 340–350 mm | 13.4–13.8 in | Compact sports |
| 360 mm | 14.2 in | Hatchback |
| 365–370 mm | 14.4–14.6 in | Modern saloon |
| 380 mm | 15.0 in | Large saloon or SUV |
| 390–400 mm | 15.4–15.8 in | Van or truck |
What Diameter Changes
Smaller rims produce a faster response for the same hand travel and feel more direct. Larger rims provide leverage and calm the input at low speed. The rack is unchanged in both cases.
When a Different Size Is Safe
A different diameter is acceptable only where the spline, hub and airbag mounting remain correct for the car. A smaller rim can obstruct the instrument cluster; a larger one can interfere with the driver's legs.
Most owners keep the original diameter and vary thickness, material and rim shape instead — those change the feel more than a small diameter step.
Before production we confirm the diameter and fitment for the exact vehicle from the chassis number and photographs.
Frequently Asked Questions
What is the standard range?
Most modern passenger cars measure 360–380 mm across the rim.
How is it measured correctly?
Outer edge to outer edge across the centre of the rim, with the wheel centred; take several readings and use the largest.
Is 370 mm common?
It is where many modern European saloons sit, which is why it appears so often in custom orders.
Can a smaller rim be fitted?
Sometimes, where spline, hub and airbag mounting match. Check instrument-cluster visibility before committing.
Does the airbag limit the choice?
The airbag mounts to the centre hub, so the fitment must be confirmed and the original core reused where required.
What else affects feel?
Rim thickness, covering and shape — usually more than a few millimetres of diameter.