Tire Fitment : What does it mean?
These tire size details can be found on the sidewall of the tire and provides important information including fitments, load capacity, speed rating, and more.
Here is a short guide that will help you understand what these indicators mean.
This indicates what type of vehicle or type of service that the tire was designed for.
P : If a tire size starts with P, the tire is a "P-Metric" size which denotes tires that are designed to be used for passenger vehicles such as cars, minivans, and light duty pickup trucks. This is the most common tire size today.
LT : If a tire size starts with LT, the tire is a "Light Truck Metric" size which denotes tires that are designed to be used for vehicles that are capable of carrying heavy cargo such as pickup trucks, SUVs, and full size vans.
T : If a tire size starts with T, the tire is a "Temporary Spare" size which designates that the tire should just be used briefly until a flat is repaired.
This indicates what the width of the "cross-section" is. So, the 215 shows that the tire is 215 millimetres across from the widest point of its outest sidewall to the widest point to its inner sidewall.
Sidewall Aspect Ratio
This indicates the tire's profile or aspect ratio. It is calculated by dividing the section height by the section width and multiplying by 100. So, in this case, the sidewall is 65% of the section width of 215.
The letter, R in this case, indicates the construction type of the tire.
R : "R" stands for a tire that has radial construction which is a design where the cord plies are laid 90 degrees from the centre of the tread. This is the most common construction type.
D : "D" stands for a tire that has "bias-ply" construction which is a design where the cord plies crisscross on a diagonal. These designs are typically used for light truck and spare tire applications.
This number indicates the diameter of the wheel that the tire matches. So, in this case, the exact size of wheel the tire will fit has a diameter of 15 inches.
This number represents the load rating of the tire which indicates the maximum amount of weight that the tire is able to support. If you want more information on the corresponding weights for each load rating, check out our Load Ratings page.
This letter represents the speed rating of the tire which indicates the top safe speed that the tire was designed for. For more information, check out our Speed Ratings page.
Load Index and Carrying Capacity
Tire experts use a "load index" to describe a tire's carrying capacity. The load index corresponds to a carrying capacity in the chart below. To find you tire's carrying capacity, look for the load index number on the sidewall of the tire.
For example, if you tire size on your side wall reads:
Then your corresponding load index would be 89.
Typically, the load indexes for tires used in passenger cars and light trucks range from 70 to 126.
Speed Ratings and Safety
The speed rating signifies the speed that the tire can safely maintain over time. These speed ratings were established to match the speed capability of the tires with the top speed capability of the vehicles.
Speed ratings are based on laboratory tests where the tire is pressed against a metal drum to reflect the appropriate load, and then it is run at ever increasing speeds until the tire's required speed is met.
A tire's speed rating can be found on the sidewall of the tire in the information for the tire's size.
In this example tire sizing, the speed rating is marked by an "H". You use this letter to match to the corresponding speed rating below.
|Symbol||Speed (km/h)||Speed (mph)|
There is a lot of useful information that you need to know on the sidewall of your tire. This information can range from size to tread wear, and it can be easy to be overwhelmed. But just look at all the information individually and try to match it to the example diagram below, and you’ll be a tire expert in no time.