By the Numbers: Tire Replacement at Auto Lab Troy in Troy
April 14, 2019
Ever notice that your tire is covered with writing? It's like some hieroglyphic art form. Of course, Troy drivers know that it's not just graffiti, but to most of us, it might as well be. Would you like to know what all those codes on your tire mean? It won't lead you to buried treasure, but it could help you make a better tire purchase at your local Troy tire store.
Prominently featured on your tire is a set of numbers and letters that looks something like this: 225 50 R 16 92 H. The first number is the width of the tire in millimeters, or the width between the sidewalls of the tire when it is fully inflated and not carrying a load. When Troy drivers replace tires, they need to match this width number, or the tires won't fit properly in the wheel wells.
The 50 is the aspect ratio of the tire, which is measured by taking the height of the sidewalls and dividing it by the tread width. If you drive off-road around the Troy area, it should have a high aspect ratio. For high performance on the road, you want a lower aspect ratio.
The R simply means this is a radial tire.
The 92 is the load rating index, or in other words, a rating of how much load a tire can safely carry. If you frequently haul heavy loads around Troy, you will want a tire with a high load rating.
The last letter in our “code” sequence is the speed rating on the tire. Not all tires have this rating. In general, the closer the letter is to the end of the alphabet, the higher the speed rating. In other words, Z is the highest rating and A is the lowest. One exception: H comes between U and V. Why? Your guess is as good as mine.
If you'd just as soon ignore all of the markings on your tire, that's okay. When you need to replace your tires just ask your friendly and knowledgeable Auto Lab Troy tire professional for his auto advice on the best tires for you and your vehicle. Replacing tires is a standard part of preventive maintenance for Troy drivers vehicles. We all have to do it sooner or later. And the better we understand what we're buying, the better our vehicle will perform and the safer we will be on Michigan roads. Good vehicle care is informed vehicle care.
Auto Lab Troy
2790 West Maple Rd.
Troy, Michigan 48084
(248) 643-7690
Need Service?
More articles from Auto Lab Troy

The Untold Truth About Blinker Fluid: Why Your Car Desperately Needs It
May 10, 2026
If youve been ignoring your dashboard, your mechanic, and that one guy at the gas station who muttered bro your blinkers sound dry, then buckle up because today we dive into the critical world of blinker fluid maintenance. What Is Blinker Fluid? Blinker fluid is a high-viscosity, luminescent com... More

No Charge (Why Won’t My Battery Hold a Charge?)
April 15, 2026
When your vehicles battery is dead, it leaves you with that horrible, helpless feeling. A dead battery means it wont hold a charge, and there are several reasons it wont. One is age. Batteries have chemical and electrical systems in them that create power, and as time goes by, they wont work we... More

In the Red (Why a Vehicle Overheats)
April 14, 2026
Heat is one thing that can damage a vehicle, especially if a problem isnt taken care of soon. Be on the lookout for signs that its getting too hot in some parts of your vehicle, starting with the most obvious one: the heat gauge/warning light on your instrument panel. When you see that heat gaug... More
