Tire Speed Ratings Explained: What it is & Why it’s Important

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As a car owner, you have a lot on your head, and the last thing you may be thinking about is the tire speed rating for your car.

However, it’s not a bad thing to think about, especially if you’re in the market for new tires.

In this post we’ll go through what tire speed ratings is and why you should consider it when picking out new tires for your vehicle!

What is a Tire Speed Rating?

A tire speed rating shows the maximum speed that a tire can withstand over time. To be precise, it is the fastest speed a tire can maintain before it weakens. Therefore, a higher speed rating provides better handling and control at high speeds.

The speed rating of a tire is done using a tire rating system. The system helps to regulate the safe performance of tires at set speeds. A tire’s speed rating is indicated with a letter from A to Z. The speed range from 3 mph (5 km/h) to above 186 mph (300 km/h)

Why Tire Speed Ratings is Important to Consider

For safety reasons it’s very important to use tires with a rating higher than the speeds you intend to drive at. If you drive faster than what the tires are intended to handle, especially for a long time, you risk damaging the tire, potentially putting yourself and others at danger.

High-speed rated tires offer better handling at higher speeds that delight most drivers. Since they are designed with soft rubber materials and stiff structure, they provide better steering response, cornering, and stopping power.

However, expect a little discomfort, shorter tread life and lower performance in cold environments when using high-speed rated tires.

Where Can I Find my Tire Speed Rating?

You can locate the speed rating in various places, normally in the manufacturer’s manual, driver’s door jamb side, glove box door, and/or hatch of the gas tank. Modern upgrading has altered almost all ratings, except unlimited ZR.

This includes the speed symbol and index of the load as a component of every tire’s service depiction on the tire’s sidewall. When you read your tire’s sidewall, the last item in the character sequence in the tire size code indicates the speed rating.

An example of the description on the sidewall of a tire is as shown below: 205/60R15 91V. In this case, the tire will have a speed rating of V. Such a tire can be driven at a speed of around 93 mph (150 km/h).

Tire Description

205/60R15 91V

205 = section width (mm)

60 = Aspect ratio

R = Radial construction

15 = diameter of the rim (inches)

91 = Description of the load index service

V = Symbol of the speed as a vector (velocity)

What is The “ZR” Marking on my Tires?

For tires with an optimum speed capability above 186 mph (300 km/h), a “ZR” may be printed in the size label, such as this; P255/75ZR-15 92Y.

Tires with an optimum speed capability above 149 mph (240 km/h) must have a “ZR” in the size label. However, if there is no service description, you can consult the tire manufacturer to get the optimum speed of your tire.

The Z implies that the tire has a speed rating of above 149mph or 240 km per hour. Upon the introduction of this speed rating, it was thought that there would be no need for designing a tire that would accommodate it.

Later on, it was realized that there was a need for higher speeds. Consequently, W and Y were developed. So, even though the “ZR must be there for any tires that can travel above 149mph or 240 km/h, you will discover the actual speed rating as W or Y.

Here are a few exampes of this:

225/50ZR16 = in excess of 149 miles per hour, 240 km per hour.

205/45ZR17 88W = up to 168 miles per hour, 270 km per hour.

285/35ZR19 99Y = up to 186 miles per hour, 300 km per hour.

Table of Tire Speed Ratings And Their Meaning

The table below shows speed ratings and symbols used.

Symbol SpeedSpeed (km/h)Speed (mph)

Do Higher Speed-Rated Tires Wear Out Faster?

There’s no need to worry about your tires wearing out faster if you put higher-rated ones on your car. Higher-rated tires simply implies that you can drive faster without overstraining your vehicle, and the speed limit will accommodate such a speed.

The durability of the tire has no direct relationship with its speed rating. Each manufacturer has unique, varied factor combinations. Different tires are available, which come in a wide range of sizes with different speed ratings as well. 

Bottom Line

The tire speed rating is different from speed limits written on highway signs. It is grounded on lab simulations and does not consider real-life factors that influence the true tire capability, such as:

How hot is the road? Is your vehicle well aligned, or ever had your flat tire repaired? Are your tires fully inflated? What is the state and age of the tread?

Therefore, do not use the tire rating as the baseline for the optimum speed you can drive. If you are driving on a tire that has been patched, low on air, or carrying a heavy load, your tire speed ability is much reduced.

So, maintain your speed at the recommended speed limit or even below for safe driving.