The phrase “one size fits all” is not true in the case of tires. For your tires to fit your car and to make sure they can handle its weight or speed, you need the right size. It’s easy to find out what tire size fits your car, whether you want to buy new tires or want to know. But you need to know the technicalities of it. If you wonder, “What size tires fit my car?”. We got you covered.
What tire size do you need?
Your car comes from the factory with wheels and tires of a certain size. There are a lot of reasons why they are that size. Engineers consider tire size when designing ride quality, gas mileage, how well the brakes work, how the car handles, how quickly the steering responds, and a number of other things that affect the total driving experience.
The maker says that the stock tire size is the best, but that doesn’t mean you can’t improve your car by making small wheel or tire size changes. This is called “plus sizing.” It could be because you want a better-looking set of wheels and tires. Or it could be for a practical reason, like improving your grip. Or maybe you have a tire size that is hard to find, and you want to switch to something more common. No matter why you want to change something, the first step is to figure out what the tire marks mean.
How to read tire size
The sidewall is made up of the outer and inner “walls” of a tire. Each panel has its own information, which is broken up into mainly three main parts:
Basic tire specs
This section includes the basic specifications of the tire. It details tire size, construction, speed ranking, load index, etc.
DOT safety code
This section is necessary as it ensures that your tire meets all safety standards the Department of Transportation (DOT) sets. After the DOT symbol is your tire’s identification number, it starts with the tire’s maker and the plant code (two numbers or letters) where the tire was made. The week the tire was made is shown by the ninth and tenth letters. The last number or numbers tell you when the tire was made.
The National Highway Traffic Safety Administration (NHTSA) created the Uniform Tire Quality Grading (UTQG) system to test tires using methods set by the government and then grade each tire based on three key factors: Treadwear, Traction, and Temperature.
Let us take an example of a standard tire size marking: P225/65R17. Here,
- P denotes the p-metric
- 225 denotes the tire width
- 65 denotes the aspect ratio
- R denotes radical construction
- 17 denotes the wheel size
The P used to stand for “Passenger,” but now P tires are common on cars, minivans, some light trucks, crossovers (CUVs), and SUVs. Another popular classification is LT-Metric, which is needed for trucks (3/4-ton and 1-ton).
Also read: Tire Talk: What Do the Numbers on Tires Mean
How to choose the right tire size for your car
Choose the size of your tires based on the vehicle’s manual and the advice of the tire maker. If the combined diameter of the wheel and tire isn’t right, the ride height and speedometer numbers could be very different.
Changing to different tire sizes can only be done by following all laws and rules and the manufacturer’s suggestions for the car, wheels, and tires. At the very least, the wheel must be able to turn in any direction, and the tire must be able to hold enough weight. As a general rule, if you go up one size in tire width and down one size in aspect ratio (the height of the sidewall), your tire size will still be the same as it was before.
Any tire that goes on a car must be either radial or bias-ply on the inside. Putting together bias-ply and radial tires on cars, caravans, and other small trucks is dangerous and against the law. This rule can only be broken if you need to use an extra tire. The same rules also apply when choosing wheels or rims. You must use the standard wheels or rims that the manufacturer of the car has allowed.
“Original Equipment” refers to tires that were designed to come standard on your specific make and model of car and were approved by the manufacturer. Some car companies, like Audi, BMW, Mercedes, and others, put tires on their cars that are made especially for their brand. On the rim of these tires, there is a special OE mark. In this case, you should only change your car’s tires with ones that have the OE marking. Here are some of the OE tires for reference:
- * = BMW, Mini
- AO = Audi
- MO = Mercedes
- MO1 = AMG
- N0, N1, N2, N3, N4 = Porsche
- VO = Volkswagen
- RO1 = QUATTRO
Can you replace all tires of your car at the same time?
Yes, you can change all four tires at the same time for the best safety and efficiency. Even though you can change less than four tires at once, there are a few rules you should follow about the size of the tires.
For example, if you only need to replace one or two tires, make sure they are all the same size and have the same load index and speed rating as the carmaker says. If you only need to replace two tires, put both of them on the back wheels. This is because the newer tires will have a much better grip, especially on wet roads, making it less likely that the car will hydroplane.
It’s not a good idea to replace just one tire because it could affect the suspension or engine of the car and cause the tread to wear out too quickly. But if you have to change only one tire, pair the new one with the deepest tread and then put both on the rear axle.
Using tires of the right size that fits your car is super important. It can not only enhance the efficiency of your car but also makes it more secure to travel in. Make sure you go through the specifications and read your car’s manual thoroughly before getting one. If you find it difficult to comprehend, seek the help of a professional.