Everything You Need to Know About Tire Weight Ratings and More

May 8th, 2020 by

A mechanic at a Cincinnati tire shop is showing a man different types of tires.

When it comes to your vehicle, it’s important you take care of it in the best way possible—by understanding what it needs and how you can service it. A car or truck can be the best tool you’ll ever have, but if you don’t understand how to take care of it, you may find its usefulness decline as it starts to have problems. Every part of the machine is important, but the tires are more essential than one might think. You may have visited a tire shop on occasion to have new tires put on, but do you know all the information attached to your set of tires?

At McCluskey Chevy, we know the importance of having good tires on your vehicle. We also know how important it is to have the correct tires on your vehicle. You may have noticed that tires come with all sorts of information attached to them on their sidewall, but not everyone realizes what it all may mean. Here, we’re going to talk about what some of the numbers on your tires mean and how that could affect how you use your vehicle.

The Breakdown

There are plenty of numbers etched into the sidewall of every tire out there, and these can give you specific information about the tire you’re looking at. For example, you might see something along the lines of LT225/75R16 on the side and feel like you’re reading a foreign language. Each letter and number is a key piece of information that reveals something else about the tire.

In the preceding example, the “LT” stands for Light Truck and the “225” is the tire width. The “75” is the aspect ratio, and the “R” stands for radial construction. The “16” is the diameter of the beads. That means this type of tire can fit onto a rim that’s 16 inches in diameter.

After those numbers, you will normally find another set of numbers plus a letter. It will look something like “97V” or “89H.” This is your load index and speed rating. The load index will be a number that has a large range, while the speed rating will be a letter that ranges from L – Z. The MPH rating of the tire will generally be higher as the speed rating letter goes farther in the alphabet.

As you can see, there are many different factors involved in the buildup of each tire. It’s easy to go to the tire shop and have them do what needs to be done, but if you understand how tires work, you can also better understand what your vehicle needs.

A closeup is shown of the code on the side of a tire, the code reads 205/45R17.

Load Index

The load index is one of the most important pieces of information you can find on a tire. This little number etched onto the tire sidewall is going to tell you exactly what kind of weight can be associated with the tire. If you haven’t noticed, your tires are holding the entire vehicle up. Add in some passengers and cargo, and that’s a lot of weight for your tires to handle. On top of that, the tires are always in direct contact with some kind of surface, whether it be pavement, dirt, or gravel. So, they’re carrying thousands of pounds of weight and constantly rubbing against different surfaces at high speeds. Needless to say, they need to be built for what they’re supposed to handle.

Most of the time, the tires that come with your vehicle will, of course, be more than capable of carrying a lot of weight capacity. If you buy a new vehicle, there are almost always high-quality tires attached to it. But what if you need to change out your tires later on or switch to some other ones for one reason or another?

If you do a quick search online, you can find entire charts of what kind of weights each tire can handle according to their load index. For instance, if you have a tire with a load index of 70, you can expect it to carry around 739 lbs. That may not seem like much, but just remember there are normally four tires on your vehicle. So, assuming all of your tires are the same, you just have to multiply the load index by four. In this case, the result would be 2,956. Generally, a passenger car will have tires with load indexes ranging from 75-100, but you could see higher. Light truck tires will often have higher load indexes.

As you move higher up in load index numbers, you can see the weight capacity increase by a fair margin. At 70, it’s only 739 lbs, but at 80 it’s 992 lbs. At 90, it’s 1323 lbs, and at 100 it’s 1764 lbs. Keep moving up, and you’ll have tires that can handle plenty of weight. If you have a big full-size heavy-duty pickup truck, you might want some tires with large load indexes to handle all of the hauling you might be doing. While many people do think about this, it can sometimes slip the mind and cause some unfortunate circumstances.

If you’re going to replace your tires, you should always get tires that have the same load index or higher of the tires that came with your vehicle (assuming those tires were correct in the first place). You normally won’t need to increase the load index of your tires when you drive a passenger car, but you might if you drive a truck. Light truck tires have two load index numbers on them, just in case they’re ever used on dually trucks, or trucks that have four tires on the back.

A closeup is shown of a summer tire on a Cincinnati, OH, road.

Load Range

In addition to the load index, there is also a load range associated with tires. It’s similar to the load index in that it’s talking about the load a tire can handle, but the load range is specifically talking about how much load a tire can carry at a specified pressure. The load range can be shown as a number (ply rating) or as a letter or group of letters (load range). Ply rating is an older method of showing the load range by counting the number of layers or plies the tire was made out of. So if there were ten plies, the tire would have a 10-ply rating.

Today, tires are still constructed with layers, but there are much fewer layers and they’re more durable. Ply rating is still used with tires, but it no longer refers to the actual number of layers in the tire. Now, the ply rating just indicates the strength of the tire.

The load range is shown with letters. Each letter is then associated with a maximum load pressure. So, a load range of B on a light truck tire would have a maximum load pressure of 35 psi, which is the amount of air you would pump into the tire. A tire with load range B could also have a ply rating of 4. They both mean the same thing when it comes to maximum load pressure.

Find Tires for Your Vehicle in Cincinnati, OH

At McCluskey Chevy, we believe in selling quality vehicles, but also making sure these vehicles stay in tip-top shape. It’s essential to know the ins and outs of your vehicle, including how your tires work. If you need your tires looked at, or some new tires put on, come visit our tire shop for high-quality discount tires.