It is very important for any driver to know the ins and outs of tire care and maintenance. As it easily wears out when not maintained properly, vehicle owners must always stay within the limits specified for a particular type of tire. Some vehicles are capable of carrying heavy loads, while some can move at high speeds depending on the equipped tire type. However, manufacturers put design limits and descriptions on tires for the drivers to know the corresponding specifications and limits.
What does the markings on the tire mean? It is especially helpful for auto repair experts to identify this to be able to carry out tire service operations.
Let’s use this for example: P 205/55R16 89H M+S
The P stands for a passenger-car tire. Other letters determine the type of tire (and consequently, the type of vehicle operation): T for temporary, as in spare tire; LT for light truck; and C for commercial. Some tires, however, do not include this letter.
The first three number, in this example, 205, correspond to the tire’s width in millimetres.
For the 55R16 segment, the 55 refers to the tire’s profile – the height of its sidewall relative to its width. In other words, it is the sidewall’s aspect ratio in percentage. For the example, the sidewall height is 55% of the tire’s width, which is 205mm. This is known as the tire’s series. Sporty tires have lower-series tires while off-road tires tend to be higher-series, designed to absorb the impact from rough surfaces.
The R means radial tire, which is a description of the way underlying layers, or plies, are laid out. For performance tires, an extra letter (from N to Z) precedes the R as a designation of the tire’s maximum speed rating in mph; the lowest is N with 87 and the highest is Y with 186, while Z is an open-ended rating that means the tire’s maximum speed is, at minimum, 150.
The 16 is the tire’s diameter, in inches, of the rim on which the tire fits.
89H is the service description. It represents the tire’s load and speed ratings. The tire’s 89 load index is equivalent to 1,279 pounds per tire, and the speed rating H represents 130 mph.
Lastly, the M+S stands for mud and snow, hence, indicating that the tire is of an all-season type. t's not the clearest of the specs, because there aren't other designations for summer and winter tires: Summer tires simply lack the M+S, and winter tires are labeled M+S and add an icon of a mountain plastered with a giant snowflake.
With these markings, the auto repair is now ready to determine proper treatment for malfunctioning or damaged tires. Conversely, by looking at the tire condition, he can also tell what kind of exploitation (or combination of such) it has gone through. Moreover, he is able to advice the vehicle user about the threshold at which a tire may simply start to go wrong.
Hence, it is imperative to have your tires checked today to avoid further hassle and hazards in your driving tomorrow.