How to Read an Earthmoving Tire Size?

Tire Size for Earthmoving Machines in Inches

In addition to the size in millimeters, the size can also be indicated in inches. An example of this is size 14.00R25. The first number shows the width of the tire. In this case, it is 14 inches wide.
The R (that comes after the 14.00) indicates that it is a Radial tire. The number 25 indicates that the rim diameter is 25 inches.
Tires with an inch size can also be swapped for a tire with a size in millimeters. For example, the mentioned tire size: 14.00R25 (inch size) is identical to size 385/95R25 (size in mm).

Tire Size for Earthmoving Machines in Millimeters

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

The first 3 digits show that the tire has a width of 750 mm. After the slash ( / ), the designation 65 follows. This is the height of the tire as a percentage of the width of the tire. The letter R indicates that it is a Radial tire. The number 25 indicates that it is a tire with a rim size of 25 inches.

Different Tire Series for Large Earthmoving Machines

For large earthmoving machines (OTR tires), the tires can be roughly divided into different series: 100-series, 80-series, and 65-series.

Note; this designation is often only found in the tire sizes that are displayed in millimeters.

A small example: in the example we mentioned above: 750/65R25, it shows that it is a tire from the 65 series. This is because the height of the tire is 65% of the width of the tire.

100-series: For a 100 series tire, the height and width ratio of the tire is identical. Here, the number 100 will be mentioned in the size indication.
80-series: Here, the ratio between the height and the width is 80%. This is indicated with an 80.
65-series: Here, the ratio is 65 percent and is indicated with the designation 65.

Load Capacity/Load Index/Speed Index for Earthmoving Machines

The load capacity of the earthmoving tires is indicated by means of a load index (Load Index, LI) for radial tires and by means of a ply-rating (Ply Rating, PR) for diagonal tires. The load index or ply-rating is combined with a speed index, which is why it is often referred to as the load/speed index.

The Tread Pattern of OTR Tires

Large earthmoving machines are mainly used in muddy conditions. It is important that the tires have a lot of traction. The tires are therefore 100% designed for off-road conditions.
There are various profiles that are suitable for specific earthmoving machines. The different codes are explained below

Tread Pattern of Earthmoving Machines

E stands for Earthmoving. This refers to machines such as articulated dump trucks. These tires are often provided with special codes as shown below.

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

Tread Pattern of Graders

G stands for Grader. The codes are listed below:
G2:Traction
G3:Rock, normal profile
G4:Rock, deep profile
G5:Rock, extra deep profile

Tread Pattern of Loaders

The letter 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