Buying tires for your car, truck or SUV can seem like a daunting, confusing task, just like anything else when it comes to vehicle maintenance. You need to know that you’re getting the right tires for your car. You also want to be sure the people you buy your tires from are selling you what you need, not just this month’s featured model.
At Next Tires, we’re the good guys: we’re tire experts who understand that our job is to get you the perfect tires for your car at a price that fits your budget.
The good news is that buying tires is actually way easier than you think. It all starts with making sure you have the right size tires for your car, truck, minivan, SUV, or whatever kind of vehicle you drive.
You shouldn’t be expected to know everything about tires to find the right tires for your car. So we want to share some of our tire expertise with you in a simple way to help you understand tire sizes and what your car needs. Here we’ll answer the following questions, so feel free to jump ahead:
- How do I find my tire size?
- What does “P” or “LT” mean in a tire size?
- What are the speed rating and load range on a tire?
- Do speed rating and load range really matter on my tires?
- How do I know I have the right tire size?
- How to read truck or off-road tire sizes (aka “flotation” tire sizes)
How Do I Find My Tire Size?
Determining your tire size is usually as simple as looking at the tires that are on your car right now.
Fair warning, this sounds way easier than you would think, but your tire size is right there on the side of your tire! Assuming you already have the correct size tires on your vehicle (and you probably do, but we’ll give you a way to verify that later), your tire size will be written, plain as day, on the sidewall of your tire.
Below is a photo from a regular car tire as a sample. Yours probably looks very similar:
In this example, the tire size is shown as “205/55R16.” Of course, your actual tire size will probably be different, but we’ll use this example to show that a tire size is typically broken down into three main numbers:
- Width (205 in our example)
- Height or aspect ratio (such as 55)
- Rim diameter (such as 16)
The first number in the tire size refers to the width of the tire. This number is actually a measurement of the width of the tire in millimeters from sidewall to sidewall, also known as the “footprint” of the tire. So our example tire pictured above is 205mm wide.
The width measures the actual tread of the tire — the part of the tire that contacts the road and gives you traction. The bigger this first number is in your tire size, the wider the tire will be.
The second number in the tire size refers to the height of the tire. It’s also called the “aspect ratio.” So, what is a tire’s aspect ratio? The height or aspect ratio of a tire is actually a percentage. It’s the sidewall height (measured from the wheel rim to the top of the tread) compared to the tire’s width, indicated as a percentage. In the example above (205/55R16), the height of the tire is equivalent to 55% of the width of the tire. Think of it this way: the larger the aspect ratio, the taller the sidewall; likewise, the smaller the aspect ratio, the shorter (or lower) the sidewall will be.
NOTE: This is why tires with the same aspect ratio won’t all look equally tall. For example, if you have a tire size of 205/55R16 next to a tire that is 285/55R18, the 285/55R18 tire will be taller because 55% of 285 is larger than 55% of 235.
The third number in the tire size refers to the diameter of the rim upon which the tire is mounted (the diameter of the actual wheel that the tire is on). In this case, the rim is 16 inches in diameter.Also note that the “R” in front of the rim diameter doesn’t mean “rim”; it simply notates that the tire is a “radial” tire. These days, you’d be hard pressed to find anything other than a radial tire, but do make sure there is an “R” before your rim diameter.
What Does “P” or “LT” Mean in a Tire Size?
Depending on the tire, you may see a “P” or an “LT” in front of the first number in your tire size.
“P” simply stands for “passenger” tire. Most cars — and even many trucks and SUVs — are considered passenger vehicles and still use passenger-rated tires. These are meant for vehicles carrying a standard load (passengers, stuff in the trunk, etc.). As opposed to…
If there is an “LT” in front of the first number, that indicates that the tire is meant for “light trucks.” LT tires typically have a reinforced (stronger) sidewall construction to be able to handle heavier loads. These are more common among work trucks, extremely heavy vehicles and the like — vehicles that are capable of carrying heavier loads.
What Are the Speed Rating and Load Range on a Tire?
In the sample tire size pictured above, you see “100V.” The number “100” is an indication of the load range of the tire, while “V” is the speed rating. Generally speaking, the higher the load range number, the heavier load the tire can handle. This number and letter may vary depending on the vehicle (97H, 103Z, etc.). For now, we’ll keep this simple — we just want you to know where to find this info and what it might look like.
Do Speed Rating and Load Range Really Matter on My Tires?
The quick answer is yes. You definitely want to make sure your tires’ speed rating and load range are appropriate for your vehicle.
When matching the load range of your tires, it is best to follow the vehicle manufacturer’s recommendation. However, if you choose tires that exceed the recommended load range, your tires should still be fine for your vehicle. So our example tire size with “100” as the load range should be fine for a vehicle with recommended load range of 100 or less (unless the vehicle manufacturer specifically states in the owner’s manual that you cannot deviate from the recommended load range).
If a tire’s load range rating is under the recommended load range, you shouldn’t buy it. If you did, you’d be putting more weight than is recommended on those particular tires. If you have any questions about load range and want to be sure, feel free to call us anytime at 1-800-360-5459, and talk to one of our tire experts. We can quickly walk you through it and get you the right tires.
Technically, the speed rating is an indication of how fast you can travel on that particular tire for 60 minutes at a constant speed … but you don’t need to worry about that The speed rating isn’t meant to coincide with how fast you’ll actually be driving. Instead, a tire’s speed rating is an indication of how well those tires will handle in order to meet the expectations of the vehicle manufacturer.
As an example, if you drive a sports car, it will likely have a higher speed rating than a big, clumsy, heavy station wagon or a minivan. Therefore, when you buy “performance tires” for your sports car, you will want to match the recommended speed rating so it handles the way it’s supposed to.
The speed rating isn’t meant for just sports cars — every vehicle has been engineered in a specific way by the manufacturer for both safety and performance. Meeting the recommended speed rating (and load range) helps any vehicle perform the way it was designed.
To put speed ratings into perspective, here’s a list of the most common speed ratings and the associated miles-per-hour speed that they can handle:
| SPEED RATING | MAXIMUM MPH |
| S | 112 mph |
| T | 118 mph |
| U | 124 mph |
| H | 130 mph |
| V | 149 mph |
| W | 168 mph |
| Y | 186 mph |
| Z | 149 mph + |
Looking at the table above, it’s pretty obvious you’re not going to be speeding around town at 149 MPH for an hour, non-stop. You will, however, come across some sharp turns, lane changes, accelerations, decelerations and other opportunities to experience the handling of your vehicle. Buying a set of tires with the right speed rating (and load range) will help your car handle the way it was intended by the manufacturer.
How Do I Know I Have the Right Tire Size?
We hear this question a lot: “I found the tire size on my tires, but I don’t know if it’s the right tire size. Can you tell me the right tire size for my car?”
If you’re not certain you have the right size tires on your vehicle, you can look up your stock tire sizes in our database by simply clicking on “Search By Vehicle Type,” and entering your vehicle information. However, there should also be a placard on the inside of your driver’s side door that tells you the recommended tire size(s) for your vehicle (see example in the photo below). You can also find this information in your owner’s manual.
How to Read Truck or Off-Road Tire Sizes (aka “Flotation” Tire Sizes)
If you have a truck or SUV, you may be seeing a completely different-looking tire size on your sidewall, called a “flotation” tire size. As an example, the tire pictured here shows “35×12.50R17LT.”
Flotation tires are typically found on off-road vehicles. These are called flotation tires because they are constructed to be able to “float” across softer soils and off-road terrain (mud, dirt, sand, gravel, etc.) better than other tires can.
If you have flotation tires, the tire size reads in the same order as standard tire sizes as shown above: Width/Height/Rim Diameter. The main difference with flotation tire sizes is that the numbers are in inches (as opposed to the metric size shown in millimeters at the top of this page).
- Flotation tire height: In the example above, “35” simply means that the tire is 35 inches tall – simple as that.
- Flotation tire width: In the example above, “12.50” means the tire is 12.5 inches wide. (We told you this was easy!)
- Rim diameter: As you guessed it, in the example above, the “17” is the diameter of the rim that the tire can be mounted on.
- LT: And, yes, you guessed it: “LT” means light truck. You’ve got this tire-size thing down!
Hopefully, this has made finding the right size tires easier for you. If not, please feel free to contact us with any questions you might have. It’s very important for safety and performance that you understand what size tires you should get for your vehicle, and we can guide you through your tire-buying journey from start to finish to make your vehicle safe, and even fun to drive!
If you’re ready to start shopping for tires, or if you just want to “kick the tires” as they say, click below to get started.
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