What does the number and letter mean after the tire size?
|Q||99 mph||160 km/h||Studless and studdable winter / snow tires|
|R||106 mph||170 km/h||H.D. light truck tires|
|S||112 mph||180 km/h||Family sedans and vans|
|T||118 mph||190 km/h||Family sedans and vans|
|H||130 mph||210 km/h||Sport sedans and coupes|
|V||149 mph||240 km/h||Sport sedans and coupes|
|W||168 mph||270 km/h||Sport sedans, coupes and sports cars|
|Y||186 mph||300 km/h||Exotic sports cars|
|Y||186+ mph||300+ km/h||Exotic sports cars|
You can see that each step up the scale results in an increase in top speed. Albeit some letters are missing (e.g. U) and not necessarily in alphabetical order, the chart does outline what ratings are appropriate for vehicles. It's important to note that some of the vehicle manufacturers sometimes specify a tire has a higher speed rating than necessary. For example, many Honda Accord vehicles have V-rating tires from the factory, which gives a 149 mph top speed on the tire. Tire Rack is very comfortable with this vehicle wearing an H-rating. We feel that being able to drive up to 130 mph is more than enough speed rating for everyday use. Does that mean that some shops will have a hard time installing an H-rated tire? Yes, some installers have taken all the guess work out of the situation and only install what the O.E. manufacturer puts on the car.
How does a family sedan that has no chance of ever reaching 149 mph in factory form have this rating specified? Higher speed ratings will handle more heat and circumferential force, which causes them to be more ridged and firm. This helps for performance handling and responsiveness to steering inputs, but can firm up road manners and result in a little more tire noise from impacts. Your lower speed ratings typically are "looser" types of passenger all-seasons and standard touring all-seasons and are not as concerned with sport performance. Winter / snow tires are the exception to the rule as most shops will install a winter tire of significantly lower speed rating. This is due to the understanding by most that the winter tires are going to make your car handle a little differently (usually a bit more play in the steering) to give you exceptional winter traction. Finally, as you are trying to determine what is best for your needs start by searching by vehicle. We do our best to offer what will keep your car handling most like the manufacturer intended. And, if you're still having trouble understanding how the tire speed ratings work, get a hold of one of our sales specialists.