Tractor tires are available in dozens of sizes to fit particular models and fulfill different types of farming, gardening and lawn care chores. The information for reading a tire size is molded into the sidewall of the tire and is expressed as a series of numbers and letters.
Although the codes might seem confusing, the numbers and letters simply denote three different measurements and the construction type of the tire. Once this information becomes familiar, understanding tire sizes is like riding a bicycle: you'll never forget how it's done.
Locate the tire size printed on the sidewall of the tire and write down this information before heading to the store for a replacement. For example, the tire size might be listed as 26-12.00R-12.
Write down "height" above the first number. In the example, the 26 refers to the height of the tire in inches.
Write down "width" above to the second number. In the example, 12 refers to the tread width of the tractor tire in inches at the widest point. The R means that it is a radial tire. The tread is the grooved surface of the tire that touches the ground.
Write down "rim diameter" above the third number, which is 12 in this example. The 12 refers to the diameter of the wheel rim in inches. The wheel rim is the width of the wheel viewed from the side when it is mounted on a tractor.