What Are Speed Ratings?

The speed rating tells you the speed a tire can safely maintain over time. A higher speed rating means you will have better control and handling at higher speeds—and that the tire can take the extra heat. As a general rule, tires with higher speed ratings also handle better at slower speeds.

The U.S. Department of Transportation (DOT) set the ratings scale shown below. Tire manufacturers test their own tires and assign their own speed ratings. On the sidewall of every tire, you will find one of these speed rating codes:

M—Up to 81 mphN—Up to 87 mph
P—Up to 93 mph
Q—Up to 99 mph
R—Up to 106 mphS—Up to 112 mph
T—Up to 118 mph
H—Up to 130 mph
V—Up to 149 mph
W—Up to 168 mph
Y—Up to 186 mph
Z—(See Below)

What does a speed rating really mean?
If you reference the list above, you will see that tires with a Q speed rating can safely sustain speeds of up to 99 miles per hour. The tire may be able to reach higher speeds, but doing so for any length of time is neither safe nor recommended.  This statement also holds true for any speed ratings.

What is a Z Rating?
For tires rated about 149 mph, a Z rating may appear in the size designation.

Safety and Speed Ratings:

  • When you get new tires, choose tires with at least the speed rating your vehicle manufacturer recommends. Moving up to a higher speed rating may be  okay but do not go lower unless you have consulted with a professional, as this may impact the handling of your vehicle.

  • The speeds shown are test speeds; they are not recommended speeds. It is always important to maintain a safe, controllable speed.

Do you have questions about what tire is right for your vehicle?  Visit a Best-One® location, and one of our trained technicians can assist you.

If I Buy A Used Car, How Do I Know How Much Life Is Left In The Tires?

Everyone knows that buying a new car can be expensive. So if you’ve decided that you’re in the market for a pre-owned vehicle, you’ll want to evaluate any potential car’s tire tread depths.

To answer this question, you’ll want to check the tire’s tread depth. To do this, all you’ll need are some U.S. coins!

1. Place a penny into the tread grooves. If Lincoln’s head is covered by the tread, you have more than 2/32″ of tread depth remaining. Click here to view an example.

2. If you’re using a quarter, when Washington’s head is covered by the tread, you have more than 4/32″ of tread depth remaining.

To check for uneven wear evaluate the tread depth in several different places throughout the tire.  It is possible for a tire to show significant wear in one spot — and less wear in another.

According to most states’ laws, tires need to be replaced when they have worn down to 2/32″ of remaining tread depth.  Another way to ensure you have at least 2/32” depth remaining is to check your tire’s wear bars. Click here to learn how.

Remember, you’ll want to ensure that any vehicle you purchase is riding on safe tires, as tread depth plays a vital role your vehicle’s ability to perform in rain and snow. If you find yourself in need of new tires, visit your local Best-One location and one of our friendly staff will be glad to help you out!

What Is The Difference Between A “Donut” Spare Tire And A Full Size Spare Tire?

You’ve probably heard a spare tire referred to as a “donut”.  Do you know how a donut is different than a full size spare tire?

A donut is a spare tire that is smaller than your vehicle’s standard tires. Since donuts are smaller than a standard tire, they usually come with a speed limitation. They are designed for limited use only.  Long term use or improper use can present safety issue for braking and traction systems. Donut spares are smaller in order to save space and are usually found in a vehicle’s trunk.

Full size spares are found on most SUV’s and full size trucks. Since these types of vehicles have a higher center of gravity, they need a larger tire – a donut is far too small.  Full size spares are the same size as the tires that come on your vehicle from the factory.

Both types of spares should be periodically checked for proper air pressure to ensure they will be properly prepared should they be needed.

If you have questions about what kind of spare tire you should keep in your vehicle in case of an emergency, stop by your local Best-One!  We’ll help keep you safe on the road.

-Jim Channel, Best-One® Tire & Service Expert Panelist