What does 108s mean on a tire?
In both cases, the "R" stands for radial, and the "H" is the speed rating (more later). The "109" in the ISO metric system indicates the load index for the tire, and the "109H" speed and load combination is often called the "service description."
If there is a "P" on the sidewall, it stands for "passenger car." This refers to the U.S. (P-metric) method of tire sizing. "LT" stands for Light Truck, "ST" is for Special Trailer and "T" stands for Temporary, which is primarily used for small spare tires.
- Megatonne (Mt), a unit of mass equal to one billion kilograms (109 kg) Megatransfer, in computing, equal to one million transfer operations per second. Metric ton (mt or MT), equal to one thousand kilograms.
- The All-Terrain T/A KO ("KO" for Key benefit On- and Off-road) is BFGoodrich's On-/Off-Road All-Terrain light truck tire developed to meet the needs of pickup truck and sport utility vehicle drivers who want confidence and control on and off the road.
- Tire load index chart and understanding your tire's code. The service description is simply the speed rating and the load rating together. In our example, the service description is the last three characters: 225/45R17 94H 94 is the load rating and H is the speed rating.
Updated: 2nd October 2019