How to read the codes of agricultural machinery tires?

Choosing tires for a tractor is important but it is also, for any type of agricultural machinery. Choosing an inappropriate tire can cause a lot of problems and if you buy a used tractor you should not worry much, but if it is a used tractor you may have more problems.

For this, it is important to know the tire codes for agricultural machinery. Knowing what all those numbers and letters mean is important, because there are more letters than in the car.

How is the tire of a tractor?

To understand this, it is vital to explain how the dimensions and shapes of the agricultural tire are. In this way we will understand correctly all the nomenclature. In this image you can see a tire (cut) that allows us to see the main dimensions:

• S: width of the ball. It would be the width of the tire section (flank to flank).
• H: flange height. It would be the height of the tire section.
• H / S x 100%: this would be the relation of form, between the height and the width of the ball.

In normal tires, this parameter is usually 100%, that is, the width and height of the ball is the same. In the low profile tires varies between 75% and 85%. On very low profile or extra wide base tires it can even vary up to 60% or 70%. Example: if we have a tire with H = 60% it means that at the height it is 60% of B.

• R: total radio without load. It would be the radius of the complete wheel without bearing any weight.
• R’: radio under load. The same as the previous one but mounted on the tractor.
• Ø: diameter of the rim.
• IC: load index or capacity. Determines the weight that the wheel can support with a particular pressure. There are tables of this.
• Speed ​​code: in addition to these, there is also the speed code A1, A2, B …, etc. These codes allow us to know what speed the tire supports.

How to read the codes of agricultural tires?

Having said all this, we can now explain how to read a code for an agricultural tire, although there may be several, according to the manufacturer. Everyone agrees to bring first the width of the ball, then the structure (radial or diagonal) and finally the diameter of the rim. Let’s give several examples.

• 20 D 30 130 A8 *

1. 20 is the width in inches.
2. D (diagonal structure) with a diameter of 30 inches.
3. 130 (load index).
4. A8 (speed code, up to 40 km / h in this case).
5. * = inflation pressure of 1.6 bar.

• 20 R 30 8 PR

It would read like the previous one, only that from 8 it changes:

1. 8PR (Ply Rating or number of canvases that would be equal to 8).

• Tire 500/65 R 30 145 A5 TUBELESS

Do it yourself, you find a 500 in width in mm, then a 65% ratio of shape (very low profile) and radial structure of 30 inches in diameter. We also find the load index 145 and a maximum speed A5, of 20 km / h. The word tubeless, in English, means that the tire does not have an air chamber.

And with this we hope we have helped you understand correctly the tire codes of the tractors.