Wheel Sizing & Markings
Wheel sizes and markings can seem somewhat intimidating at first, especially if you are just looking for a new set of wheels for your car and are being bombarded with letters, numbers and offsets. What we will do is break down the jargon and explain each part of the wheel markings.
6.5J x 17 H ET35
Firstly lets break this down into the seperate parts.
- 6.5 - This is the wheels width in inches from the front of the rim to the back.
- J - The J indicates the bead profile, a full table of these is below.
- 17 - This is the wheels diameter in inches.
- H - This represents the hump type and will be a good indication of wheel rigidity.
- ET35 - This is the wheels offset. A measurement in mm showing how far away from the wheel centreline the wheels meet the hub. Check below for a diagram on offset.
Wheel offset is how far away from the centreline (the red dashed line on the diagram below) your allow wheel makes contact with the hub.
The greater the offset the closer your wheel is to the axle and steering and suspension components, and the lesser the offset pushes the wheels out to the road side and closer to the the wheel archers and body panels.
Zero offset means that the centreline of the alloy is in line with the point at which the wheel is attached to the car.
Along with wheel sizing, tyres have their own various markings, these are similar in the way wheels are marked in that they show the sizing, construction and safety information for the tyre.
Again, lets break this down into its parts
- 215 - Tyre width in mm from sidewall to sidewall
- 45 - Aspect Ratio for the tyre, the height of the sidewall of the tyre as a percentage of the width. In this instance 45% of 215 is 96.75mm meaning that is the height of the tyre sidewall.
- R - Tyre construction type. Most modern tyres today are manufactured as radial tyres and have the R type, other types include B for bias belt and D for diagonal.
- 17 - Tyre diameter in inches, Easier to match to the wheel size which is usually represented in inches too.
- 107 - Load Index. A numerical code referring to the maximum load the trye can carry.
- W - Speed rating. A table of these is below but this tells you the maximum speed the tyre is rated for at its maximum load.
Load Index Table
|Load Index||Kilograms||Load Index||Kilograms||Load Index||Kilograms|
Speed Index Table
|Speed Symbol||Approx MPH||Approx KM/H|
Wheel Marking table
|A||Bikes, Motorcycles, light and heavy trucks and forklifts|
|D||Bikes, Motorcycles, light and heavy trucks and forklifts|
|E||Light & heavy trucks|
|G, H||Heavy trucks|
|P, K||Antique cars|
|S, T, V, W||Utility vehicles|