How to read a tire? The first rules are...
Many of you deal with Off-Highway tires on a daily basis. So, you can probably choose a tire, judge its performance and make out possible failures. But are you able to recognize a tire from its code? Which are the rules to read a tire? Let’s find out together!
Off-Highway tires have their “identity card” hot stamped on the sidewalls. Every important piece of information is tagged on the tire, you just need to know where to look for it.
The tire marking shows a series of references, abbreviations and codes specifying the tire features. Some information is mandatory, other is voluntarily given by the manufacturer. In addition to the tire dimensions, performance features and construction data (structure and production date), we can find references on the brand, the tire name, tire size, safety information, load and speed indices, instructions on pressure, tire type, rolling direction, and the serial number.
When changing a tire on agricultural machinery, the tire size is likely to be the feature we are mainly interested in.
The main parameters for measuring a tire are:
- Overall Diameter (OD)
- Section Width (SW) without the prominences due to tire marking.
- Overall Width (OW) measured at its widest point, including all prominences due to tire code marking.
- Section Height (SH) refers to the tire’s vertical section. It is calculated from the overall diameter less the rim diameter and then divided by two.
- Static loaded radius (SLR) is the distance between the ground and the tire rotation axis with the tire inflated at nominal pressure, fitted on the reference rim at maximum load according to the load index.
- Static loaded width (SLW) is the maximum distance between the tire sidewalls with the tire inflated at nominal pressure, fitted on the reference rim at maximum load according to the load index.
But, which of these measures are given in the marking? Well, it is not so easy to answer this question. Unfortunately, there are different modes to write the tire code. Little by little, we will go into it and answer questions like these:
How to read a tire? What do letters and numbers refer to? Are measures expressed in centimeters or inches? Is the code on an agricultural tire written differently to that on an OTR tire?
Follow us over the coming weeks for some training on reading the main Off-Highway tires. Stay tuned!