Stuff only your dad knows: Speed rating for tires

Your dad tells you that you need new tires. He pulls out a Lincoln penny and shows you that too much of Lincoln's head is visible between the tire treads. He chides you for letting them go so long. You tell him it's not easy to buy a set of tires on a just-out-of-college salary (and he doesn't catch the hint). As he launches into his tire speech, your eyes glaze over and your mind wanders off. Then he says something about "speed ratings," and you realize you probably should have paid attention. Here's what he was talking about.

Speed Rating Defined.

A tire speed rating tells you how fast you can go on a tire based on the weight of your car before the tire fails. The higher the speed rating, the faster you can go and still rely on your tires to perform. Without the proper speed rating, you risk a blow-out while traveling at a high speed and losing control of your car. Higher speed ratings also give you greater control over your car when traveling at lower speeds. You can use tires with a greater speed rating than required by the manufacturer of your car, but do not choose one lower.

Using tires with the proper speed rating improves the comfort of the ride and the vehicle's cornering ability. The higher the speed rating, the greater control you have over the car and the greater the stopping power.

Correct Speed Rating.

The speed rating for the tire is marked on the tire itself. The speed rating is only accurate if you are using undamaged tires. Tires that have been repaired because of blow-outs or old tires with new treads are not guaranteed to live up to the speed rating originally given them.

The owner’s manual for your car will tell you the recommended tire speed rating for your vehicle. Ask your tire dealer to help you choose the right tire with the proper speed rating. For example, if you are choosing TireBuyer Nexen tires, the dealer will not only account for vehicle manufacturer recommendations, but he'll ask you questions about your driving style and habits to ensure you choose the right ones.

You can also find the recommended tire speed rating by checking the tire placard found on the side of the driver’s door or on the door to the fuel tank. This placard should give you all the information you need to purchase new tires.

Mix-matched Tires.

Driving a vehicle with tires that have mismatched speed ratings decreases your control of the vehicle. Steering is unpredictable and overall handling of the car is compromised. Mismatched tires increase the chance of tire failure on the road, such as having a blow-out at a high rate of speed. Also, tire rotation is not recommended with mismatched tires. If they are mismatched, they will still wear unevenly even with regular rotation.

Following the speed ratings lesson, you get it now. Thanks, dad.

Taken from: Guest Post (article, By Gerry Lane), Google (images).