What Do Tire Numbers Mean

Tires are the most easily worn parts of a vehicle. When your car has been driven for six or seven years or has traveled 60,000 to 70,000 kilometers, will the mechanic suggest you replace the tires during maintenance? They will say that your tires are severely worn and cracked, and it is unsafe to continue using them. So, do you know how to choose the right tires for your car?

Today I will explain to you about this, hoping that you can understand more about tire information, which may be helpful the next time you change tires.

What Does 215 50R17 Mean on A Tire

Let's first talk about the most important tire specifications, because different specifications of tires will affect the performance and comfort of the whole vehicle.

The tire specifications are usually marked on the side of the tire using the ISO international quality certification method. Let me give an example to explain their meanings in detail, such as: "P215/50R17 91V" on the tire in the figure below.

P Meaning

The first portion of the code is made up of 1 or 2 characters (P, LT, ST, T) that describe the type of vehicle that the tire is meant to be used with. There are 4 vehicle classes:

P stands for passenger car. Vehicles such as automobiles, SUVs, crossovers, minivans, and light pickup trucks are designed to use tires with the P standard.

LT stands for light truck. Tires with the LT specification can tow trailers and are made to support large weights.

ST stands for special trailer. Trailers including travel trailers, utility trailers, and boat trailers use these kinds of tires.

T stands for temporary. Typically, spare tires with the T standard are not meant for daily usage.

215 Meaning

The first number "215" represents the width of the tire. Simply put, we can roughly understand that the width of this tire is 215mm.

The width of the tire often determines its grip effect, so for the same brand and model of tire, the wider it is, the smoother the driving and the better the braking effect.

However, the wider the tire, the more it will affect the power and fuel consumption of the car, so the wider the tire is, the better it is.

50 Meaning

The second number "50" represents the aspect ratio, which is the percentage between the tire section height and the tire section width, that is: tire thickness ÷ tire width x 100%.

The larger the aspect ratio, the thicker the tire wall, the more air stored in the tire, the stronger the cushioning capacity, and the higher the comfort; conversely, the smaller the aspect ratio, the thinner the tire wall, and the relatively poorer comfort.

Letter R Meaning

The letter "R" after the number "50" stands for Radial tire. Almost all family cars on the market currently use this type of tire.

17 Meaning

The third number "17" represents the rim diameter. The number "17" after the letter "R" represents that the rim diameter is 17 inches. Common sizes include 13, 14, 15, 16 and 17.

91 Meaning

The fourth number "91" represents the load index. The number "91" after the letter "R" represents the load index, and its corresponding load is 615kg. Each load index has a corresponding loadable mass.

It represents the maximum pressure-bearing capacity of the tire. The larger the value, the greater the tire's pressure-bearing capacity.

Letter V Meaning

The last letter "V" represents the maximum speed that the tire is suitable for. It is divided into different levels such as A-Z. The later the letter is, the better the tire performance is and the higher the speed it can carry.

How to Choose the Right Size of Tires

A tire size calculator is a quick way to ensure a new set of tires will fit your vehicle, SUV, sports car, light truck or crossover. But remember, this calculator is merely an estimate. It is critical that you adhere to your vehicle's sizing tolerances. The wrong size tire may create steering wheel pull, rub against your vehicle's suspension or body, restrict hill clearance, or result in a stiffer or noisier ride.

Tips on Choosing Tires

There are many types of tires on the market, and there are four types of tires. Although they sound attractive, they are not ideal for family cars.

1. High wear-resistant tires

High wear-resistant tires sound practical because they have a long service life and can save tire replacement costs. But in fact, this type is generally built for taxis. In order to achieve a longer service life, high wear-resistant tires often sacrifice tire grip and softness. This will result in insufficient tire grip on slippery roads or emergency braking, increasing braking distance, thereby reducing driving safety. For family cars, safety is always the top priority, so it is not recommended to choose high wear-resistant tires.

2. Sports tires

Sports tires are also not suitable for family cars. Sports tires are usually designed with a lower aspect ratio and a larger tread width. Although such a design can improve the handling and stability of the vehicle, it also brings problems such as high noise and poor comfort. Moreover, the price of sports tires is usually higher, which is not a cost-effective choice for family car owners who pursue cost-effectiveness.

3. All-season tires

Let's talk about all-season tires. All-season tires seem to be able to cope with all weather conditions, but in fact, it is difficult to take all aspects into account. In extreme weather conditions, the performance of all-season tires is often not as good as specially designed winter tires or summer tires. For example, on snow or ice, the grip of all-season tires may not meet the needs of safe driving. Therefore, for family cars that often need to cope with different weather conditions, it is safer to choose special winter tires or summer tires.

4. All-road tires

Finally, we should be wary of all-road tires. All-road tires were originally designed to adapt to various road conditions, including off-road, gravel, mud, etc. However, such a design also leads to poor comfort and handling of tires on the road. For most family cars, most of the time is spent on the road, so it is more appropriate to choose tires designed for the road. In summary, although high-wear tires, sports tires, all-season tires, and all-road tires have certain advantages in some aspects, they are not ideal choices for family cars.