Tire Combinations

RXA0057453-UN-04OCT01

Step Identification (Independent Link Suspension)

RXA0096584-UN-13NOV07

Step Identification (1500 MFWD Axle)

A - Marking Location, Independent Link Suspension

B - Marking Location, 1500 MFWD Axle

C - Divot

IMPORTANT: Avoid excessive drive train wear. Do not mix worn and new tires, bias and radial, or tires of different diameters. Do not use R2 tires in combination with R1.

With the tire industry converting to metric designations, there are many new terms which can be confusing. To simplify things, tires are placed into groups by their Rolling Circumference Index (RCI). Rolling circumference is the distance a tire travels in one revolution. Tires within a group, regardless of rim size, are the same or nearly the same height. Knowing and understanding RCI and group sizes makes choosing front and rear tire combinations easier.

RCI is important for proper MFWD and Independent Link Suspension tractor setup. With both types of front axles, front and rear tires do the work. Since front tires are smaller than rear tires, front tires have to rotate faster to cover the same distance as the rear. Therefore it is important to select the correct size to optimize efficiency and ensure longer tire life.

Tractors equipped with 1300 MFWD axle always have front tires that are five group sizes smaller than the rear tire group. Tractors equipped with Independent Link Suspension have a ”4” or ”5” marking (A) stamped on the right side of front differential housing. Tractors equipped with 1500 MFWD axle, have a ”4” and a ”5” marking (B) stamped on the right-hand side (B) of the front axle above the steering cylinder. A divot (C) is stamped beside the appropriate number for that tractor. This marking identifies axle gear ratio and the difference in tire group size required.

The front tire must be from a group that is four or five group sizes smaller than the rear tire group. For example, if the rear tires are group 47, and the front differential is stamped with ”5”, then the front tires must be group 42. The rim size is of no consequence. Different rim-size tires such as 18.4R46 and 20.8R42 have the same rolling circumference, which is 47. Tire sizes for 8030 Series Tractors are found in the table on the following page.

MFWD front tire size combinations must be matched with the rear tires. It is not recommended tire combinations be changed without consulting your dealer. Mismatched tire sizes effect electronic transmission control, which may vary tractor ground speed. Mis-matched tires may also increase wear on tires and drive train components.

If you have any questions or need assistance in choosing the correct combination, see your John Deere dealer.