How do you read an earthmoving tyre?

Reading the tyre size of large earthmoving machines such as loaders or dump trucks can be quite a challenging task. In this article, we explain what to pay attention to and how to do this correctly. Tyres for earthmoving machines are also known as OTR tyres (Off-The-Road tyres).

First of all, you should pay attention to the following: on earthmoving machines, the tyre size can be displayed in two different ways: in inches or in millimetres. It is important to remember that for every tyre size displayed in inches, there is also an equivalent size available in millimetres, and vice versa.

Calvin van der Burgt09-04-20263 minutes

Earthmoving tyre size in inches

In addition to millimetres, the size can also be indicated in inches. An example of this is size 14.00R25. The first number shows the width of the tyre. In this case, it is 14 inches wide.

The R (which comes after 14.00) indicates that it is a radial tyre. The number 25 shows that the rim diameter is 25 inches.

Tyres with inch sizing can also be replaced with tyres sized in millimetres. The tyre size 14.00R25 (inch sizing) is identical to size 385/95R25 (mm sizing).

View all OTR tyres

Earthmoving tyre size in millimetres

The size designation of a large earthmoving tyre is structured as follows: 750/65R25.

The first three digits indicate that the tyre has a width of 750 mm. After the slash ( / ) comes the number 65. This represents the height of the tyre as a percentage of the tyre width. The letter R indicates that it is a radial tyre. The number 25 indicates a rim size of 25 inches.

View all OTR tyres

Different tyre series for large earthmoving machines

For large earthmoving machines (OTR tyres), tyres can generally be divided into different series: 100 series, 80 series, and 65 series.

Note: this designation is usually only found in tyre sizes expressed in millimetres.

Example: the size 750/65R25 indicates a 65 series tyre, meaning the height is 65% of the tyre width.

100 series: height and width are equal (100%).
80 series: height is 80% of the width.
65 series: height is 65% of the width.

Load capacity / load index / speed index

The load capacity is indicated by a load index (LI) for radial tyres and a ply rating (PR) for diagonal tyres. This is often combined with a speed index.

Tread pattern of OTR tyres

Earthmoving machines operate in muddy conditions, so tyres are designed for maximum traction and off-road use.

Different tread patterns are used depending on the machine.

Tread pattern for earthmoving machines

E stands for Earthmoving.

E2: Traction
E3: Rock, normal profile
E4: Rock, deep profile
E7: Flotation

Tread pattern for graders

G stands for Grader.

G2: Traction
G3: Rock, normal profile
G4: Rock, deep profile
G5: Rock, extra deep profile

Tread pattern for loaders

L stands for Loader.

L2: Traction
L3: Rock, normal profile
L4: Rock, deep profile
L5: Rock, extra deep profile
L3S: treadless
L4S: treadless, thick tread
L5S: treadless, extra thick tread

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