What Do The Numbers On The Side Of A Tire Mean?

Whether you’re switching out your tires for a different look or added performance, a good place to start your search for that new tread is the sidewall on one of your existing tires.

The numbers and letters on that sidewall represent everything from the tire type and width to the aspect ratio, construction type, diameter, load index, and speed rating. Here’s how to read the sidewall on your tires.

? Tire Size Meanings:

The numbers and letters on the sidewall can be confusing. Here’s what each one means.

1. TIRE TYPE:

The first letter in the code tells you what class of tire it is.

?? P stands for passenger vehicle tire. P-class tires include cars, SUVs, crossovers, minivans and smaller pickup trucks, as well as EVs (electric vehicles). While the right load capacity can be achieved for electric vehicles with a standard passenger vehicle tire, special EV tires may be available for some vehicles. Look for the letters EV on the sidewall.

?? LT means light truck tire, designed for vehicles capable of carrying heavy loads, towing trailers, or for those looking for an extra heavy-duty option. These are often equipped on three-quarter or 1-ton trucks and SUVs.

?? ST stands for Special Trailer. These tire sizes are meant for trailers, including fifth wheels and other travel trailers, as well as boat and utility trailers.

2. TIRE WIDTH:

The three-digit number following the letter is the tire’s width (from side to side, looking at the tire head-on) in millimeters. This may also be referred to as the section width.

3. ASPECT RATIO:

The forward slash separates the tire width number from the two-digit aspect ratio. The bigger the aspect ratio, the higher/taller the tire’s sidewall, or “profile” as it’s sometimes called.

The aspect ratio is indicated on the tire sidewall as a percentage. It’s the height of the sidewall measured from the wheel rim to the top of the tread, expressed as a percentage of tire width.

4. CONSTRUCTION TYPE:

This single letter tells you about the internal construction of the tire. These include radial and bias.

?? R: Radial Tires: R is for radial tires, the industry standard for most tires today. They have better road grip, lower rolling resistance for better gas mileage or electric range, and ride comfort and durability than previous generations of tires.

?? D: Diagonal Plies or Bias-Constructed Tires: D is for tires built with diagonal (crisscrossed) plies, called bias-constructed tires. They are also called conventional, x-ply, or cross-ply tires. Some motorcycle and trailer tires still use this internal construction.

5. WHEEL DIAMETER:

This two-digit number specifies wheel diameter in inches. It’s the distance between the two bead seat areas (where a tire gets tightly sealed onto the wheel).

6. LOAD INDEX:

The two-digit or three-digit number that follows the gap specifies the tire load index. The load index symbol indicates how much weight a tire can support, based on the following standard chart (see below). In our example, the load index is 89.

7. SPEED RATING:

The last letter is the tire speed rating. This indicates the top speed it’s safe to travel for a sustained amount of time. A tire with a higher speed rating can handle heat better and provide more control at faster speeds.

#viralpost #automotive #automobile #mechanic #mechanical #engineering #cars #engine #Tires #usa #australia