Wheels, Tyres & Innertubes
How to determine which tyre to buy
Look at the sidewall of your lawn tractor tyre. There should be a series of numbers or numbers and letters on it. If you don't see anything, try washing the tyre to make them appear.
Count the numbers and determine the size from the numbers. The number sequence has either two or three numbers. In two-number sequences, the first number of the sequence is the width in inches, and the second number will be the diameter of the rim in inches. For exampe, if the sidewall of the tyre reads "12.4-26", that means the width of the tyre is 12.4 inches and the diameter of the rim is 26 inches.
Determine the size if there are three numbers. For three-number systems, the first number is the height, the second is the width, and the last number is the rim size. So for a tyre that reads "15/6.0-6," the height is 15 inches, the width is 6 inches, and the rim size is 6 inches. This might also be written as 15x6.00-6 which is the format we will use to describe the tyres.
What does the Ply rating mean?
The Ply relates to the Load Range. This indicates the maximum load recommended for the tyre. This varies by tyre size and inflation pressure: A bigger tyre can hold more air and can be rated for a higher load. Also, a given tyre size at a higher air pressure results in a higher rated load. 2-Ply tyres are rated load range "A" and 4-ply tyres are rated load range "B" (higher). You should consult your owners manual to determine which ply-rating to buy but you will probably find the larger tyres only come as 4-ply anyway.