How to read the wheel markings?

  • Author: OPONEO.CO.UK

Located on the inside of the wheel, wheel markings are a series of numbers and letters that provide coded information about the wheel such as its diameter, width or offset. However, you need to know how to read them - and once you do, you will see there is much important information left for you.

The sequence of numbers and letters help to identify not only the appropriate car wheels, but also other attributes and features. Have you ever wondered what the mysterious letter “J” means (the one placed after the number indicating the rim width, in inches)?

Likewise, not many drivers know what the “H2” at the end of the size symbol stands for. Read on to find out what structure or parameters of the wheel they symbolise.

wheel-markings

What do these mysterious markings on car wheels mean?

Wheel markings explained

To better illustrate the meaning of the markings, let's take a look at the following example: "7.5Jx16H2 ET35.” In this case:

  • 7.5 is the wheel size, meaning it is 7.5 inches wide (1 inch = 25.4mm)
  • 16 is the wheel diameter, also expressed in inches
  • ET35 is the offset - the distance of the hub mounting surface to the wheel’s symmetry axle expressed in millimetres.
     

The size, diameter and ET are wheel dimensions. We need to know them when searching for appropriate products for our cars

The letters J and H2 in the letter and number combination

The letter “J” means a tyre bead profile. This is the marking used to define the wheel collar profile you should never ignore. Wheel collars and tyres must be compatible. There are various types of wheel edges listed as follows:

Symbol  Use
A Bicycles, mopeds, motorcycles, scooters, vans, lorries, forklifts
B Old wheels up to 6" wide, sometimes found on the old VW Beetle
D  Bicycles, mopeds, motorcycles, scooters, vans, lorries, forklifts
E Lorries, vans, tractors (front wheel drive) with "semi-drop" wheels (see below)
F Vans, lorries, forklifts with "semi-drop" wheels
G, H Vans, lorries with "semi-drop" wheels
J Passenger cars
JJ 4x4 SUVs
P, K  Found sometimes in older cars such as VW Beetle, Jaguar
S Commercial vehicles with "flatbase" wheels (see below)
T, V Commercial vehicles with "flatbase" wheels
W Agricultural tractors, mainly on the rear axle

The edges of these different types may sometimes differ from one another. It's important to remember that some types of cars and wheels can come under more than one profile.

Why collar profiles always matter

The key thing is compatibility - take a look at an example illustrating a cross-section of the popular 6-inch wide wheel. The example shows the difference between “J” and “B” collar profiles.

Despite the fact that both wheels are designed for use with a passenger car, it’s forbidden to use car tyres designed for “J” with wheels using the “B” profile. You should make sure that your wheel collars and tyres match at all times.


differences-between-b-collar-vs-j-collar

The profile for a 6 inch wide wheel and the difference between "B" and "J" collar profiles.

Profile cross-section in detail

H2” is a wheel rim section profile symbol. It's usually found at the end of the alphanumeric symbols stamped on the wheel. In order to obtain the required stiffness, manufacturers strengthen the wheel structure with humps.

The outline of the passenger car wheel with the H cross-section profile, J collar and 5° wall tilt by ETRTO

Wheel contour production designs

As for the wheel collars, there are certain contour design options for wheels. The following table shows all the possible shapes of a passenger car wheel rim interior. A 5° rim wall tilt is required.

Wheel cross-section profiles with a 5 ° wall tilt.

Profiles no longer used in passenger cars

The following wheel profiles are no longer used in passenger cars:

  • Semi-drop
  • Flatbase
  • Divided
  • Drop-centre
  • 15 ° drop centre

While they can still be found in trucks, vans and agricultural vehicles, they are not used in any passenger car any more. As such, you are highly unlikely to come across them for your own car tyres and wheels. For the purposes of information, we will still present you with their shapes so that you can have a basic idea of the profiles discussed.

other-unused-wheel-profiles

 Various truck, van, agricultural and industrial vehicle wheel profiles.

Apparently, the code engraved on your car wheels isn't that mysterious. If you know what the symbols mean, you can easily find out all you need to know to have the perfect tyres mounted. As long as you know what size and profile your car wheels are, you can use our website to choose the best tyre sizes. Choosing an ideal set for your vehicle and driving style is only a few clicks away.

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