Z Rated Tires Mph
Mph w speed rating and 186 mph y speed rating.
Z rated tires mph. The speed rating system used today was developed in europe in response to the need to control the safe performance of tires at standardized speeds. The w of the 91w means the above yokohama advan neova is w speed rated. The higher the speed rating the better control and handling youll have at higher speeds. Anything rated for more than 149 mph is considered a z speed rated tire and sometimes the manufacturer will stick the z in the size right before the r to denote a z speed rated tire.
A letter from a to z symbolizes a tires certified speed rating ranging from 5 km h 3 mph to above 300 kmh 186 mph. That ultimately caused the automotive industry to add w and y speed ratings to identify the tires that meet the needs of vehicles that have extremely high top speed capabilities. The rating is molded on the tire sidewall signified by a letter or two usually after the load index number. Tires with z ratings were originally thought to be to the highest rated tires a vehicle would require.
Where have they gone. The introduction of exotic sports cars with extremely high top speeds ultimately caused the creation of the w and y speed ratings to identify tires that meet the needs of such vehicles. The tire speed rating is the maximum speed tires can safely carry a load the original weight of your vehicle plus whatevers in it for a sustained amount of time in ideal conditions. Some manufacturers will insert a z in the middle of the tire size description right after the aspect ratio when the tire is rated at w or y and if a tire is rated in excess of 186 mph 300 kph manufacturers usually will list a z within the size description per industry standards.
While z speed rated tires are capable of speeds in excess of 149 mph how far above 149 mph was not identified. Since z means 149 mph any w or y speed rated tire is z speed rated. Tire speed rating and why it matters. In the above picture youll see 91w to the right of the size.
The z rating may appear on any tire rated above 149 mph. A tires certified speed rating is given a letter from a to z ranging from 5kmh 3mph to above 300 kmh 186 mph. Not all z speed rated tires have a z listed on the sidewall in this manner because it is not mandatory. Speed ratings are as follows.
However the development of faster vehicles led to the production of two new speed ratings w and y. While z speed rated tires are capable of speeds in excess of 149 mph the z rating did not specify how far above 149 mph.