Smart Motorist » What Tires Fit My Car?

What Tires Fit My Car?

You might want to replace your car tire, but the thought of what tires fit my car becomes a setback. Getting the right tires for your vehicle is paramount to vehicle efficiency and safety.

Your choice of the tire should mirror your driving conditions and your preferences for vehicle reaction and handling. You have to know what is the right tire size for your car to make the perfect choice when the time to replace comes.

Deciding the accurate tire size for your vehicle is reasonably straightforward. Keep reading to learn how to know what tires fit your car.

How to Determine the Perfect Tire Size for Your Car

The use of a three-number code assigns tires sizes. For example, for tire size series 255/55/16, the aspect ratio is 55, 2555 is the breadth, while 16 is the inner diameter size.

The external width of the wheel gets calculated by the length between the ends of each sidewall. To find the inner diameter, the aspect ratio of the wheel, and the rim size, remove an inch from the external width.

Multiply the aspect ratio of the wheel by two to find the external width, including the top and bottom sidewalls, and add it to the inside diameter. Then convert to inches from millimeters, this would give you 25.7inches as the measured height.

When you get the external width of the old wheel, cross-reference it with the replacement width, which is how to find out what is the right tire size for your car.

How to Know Tires That Would Fit Your Car

Recent car models have bigger wheels and larger tire sizes. Bigger tires give your vehicle a more elegant, sleeker look and make driving safer. The part of the wheel that is between the inner and outer diameter is called the sidewall.

The more the sidewall, the higher the cushion. Cars with 18-20 inch wheels have narrow sidewalls. The riding experience of such vehicles is slightly uncomfortable but possesses better handling. While for cars with higher sidewalls, the ease of handling gets reduced experience.

Where Do I Find My Tire Size

Where Do I Find My Tire Size

It is easy to find out the correct tire size of your car because the information you seek is in the vehicle owner’s manual. If you want to replace the tires head over to the manufacturers, they could provide a tire size chart catalog.

If the manual is unavailable, look out for the tire fit guide by the car glove compartment or gas tank handle. Then use it as what tires fit my car calculator guide. You can also use the speed rating and load index to find the right tire sizes.

You can also find tire size by VIN. When you find the tire size data, you would also have to figure out the letter and number series.

How to Interpret Tire Size

Use the image below to understand better what the numbers or letters that appear on the data stand for. We would use tire size P225/70R16 91S as an example.

Letters “LT” And “P”

The letter “P” appears before the number series, for our example, P225/70R16 91S. The “P” is a short input for “P-metric,” and it means “passenger car” type by the Rim and Tire Association.

To be chiefly used by passenger cars and other light pickup trucks. If it is labeled “LT” and not “P,” it means you need “light truck” tires. “LT” is abridged for “LT-metric” and are made primarily for vehicles moving heavy cargos or trailers.

Other letters include “T,” which means “temporary” is used as spare tires, while “ST” denotes “special tires.”


The first number that appears on the tire size data is the width, and it is measured in millimeters. For our example P225/70R16 91S. It means that the tire has a nominal width of 225 millimeters and is a passenger vehicle. The width of the tire can be gotten by measuring one end of the sidewall to the other.

Aspect Ratio

The next number following the slash is the aspect ratio of the tire. It lets you know how long the profile of your tire is. It gets denoted in percentage.

In the case of our tire P225/70R16 91S, 70 is the aspect ratio, which means the height of the tire is seventy percent of its width. Tires with low aspect ratio, like 60 series, offer better handling performances than tires with a high aspect ratio.


The letter after the aspect ratio shows the kind of inner construction caring for the stability of the tire. The two kinds of construction that can be found on the sidewall of a tire. The constructions are R, which stands for Radial and D, which stands for Diagonal, are commonly called Bias Ply.

In our case P225/70R16 91S, the construction is Radial. It means that the inner ply cord of the tires gets arranged radially, perpendicular to the rotation axis.

Diameter of Rim

Diameter of Rim

After the construction, the sequential number is called a diameter code. It is measured in inches of the rim, in which you mount the tire. In our example, our tire of size P225/70R16 91S will perfectly fit a 16-inch diameter rim.

Load index 

The next number in our series after the rim diameter is the load index of the tire. It lets us know how much weight the tire can carry when it gets fully inflated. It is measured in pounds.

It is called load “index” because the number does not tell the exact amount in pounds that the tire can support, at most not alone. For our example P225/70R16 91S, 91 is the load index.

Speed Rating

The last figure in the size series is called the speed rating, and it is designated with a letter. Speed rating correlates to a specific speed established based on a standard lab test.

If a car has tires of varying speed ratings, this speed of the car is dictated by the tire with the “slowest” speed rating.

Tires designated with “S” has speed rating rated up to 112 miles per hour (mph), while tires rated as “R” are up to 106mph. In our case with tire P225/70R16 91S, our speed rating is designated “S.”

Wrap Up

This article explains in detail the question, what tires fit my car? You would need to determine the tire size to know which tire to buy.

It is not enough to know the answer to what tires fit my car. You have to also decide what brand of tire you would prefer. There are various brands of tires in the market to choose from. Some popular brands include Goodyear, Michelin, Bridgestone, and Kumho.

You can buy tires from automotive shops near you, or if in doubt, go to big shopping malls and ask for the auto section. For example, Walmart has a whole section for Walmart tires.

Kindly drop a comment if you have further questions or contributions.