If you have shopped for tires recently then you know that there are just as many different tires out there as there are cars. But while the options may seem endless the standard to which they are all held is the same. While the average person doesn't typically worry too much about the speed ratings on their tires it's good information to have and understand, especially if you are considering tires with a higher speed rating. Unless you frequent the race track, or like getting speeding tickets, most of us drive within the posted speed limit, which on the highway is about 75 mph. However, there are places in Europe, like the Autobahn, that allow drivers to go much faster than that. It is for this reason that speed ratings on tires were developed. Tires were not manufactured to handle such speeds and too many people experienced blowouts and bad accidents as a result of tire failure. Now tires are rated for specific speeds to fit the needs of the driver and the vehicle. A typical tire rating will imprinted on the sidewall of your tire and look something like this P195/60R15 87S. The speed rating is denoted by a single letter, L-Z, at the end. In this case it's an "S". (Prior to 1991 the speed rating was incorporated in the rest of the rating.) Each letter represents the maximum speed that the tires are rated for. L-75mph M- 81mph N- 87 mph P- 93 mph Q- 99 mph R- 106 mph S- 112 mph T- 118 mph U- 124 mph H- 130 mph V-149 mph Z- in excess of 149 mph W- 168 mph Y- 186 mph While it may be tempting for some to get a higher rated tire, like Z or W, the life of the tire decreases dramatically the further up you go. But if you plan on taking your Procomp tires out for a spin on the fast track it's best to have tires that are rated for the higher speeds.