A Complete Guide To Tyre Speed Ratings

As a car owner, it’s important to understand tyre speed rating, load index, and tyre size. When it comes to buying new tyres, you can’t live without this information – understanding tyre speed ratings and how they affect which tyres you can use on your car is essential.

Tyres have their size, speed rating, and load index labelled on their sidewall. Knowing how to read this information is one thing, but knowing what each marking actually means is another. This blog will help you to understand the tyre speed rating so you can choose the right tyres for your car.

What is a tyre speed rating?

A tyre speed rating is the maximum speed that the tyre is legally approved to be driven at, based on the recommended load index that’s also on your tyre. These speed ratings are based on practical tests that engineers run when new tyres are designed – making sure the tyres can safely reach high speeds.

Can speed rating affect my driving?

The best quality tyres have better braking, grip on wet roads, and more responsive steering. If you use tyres with the wrong speed rating, it could contribute to dangerous driving as steering response will undoubtedly be affected. Installing the wrong type of tyres on your car can also void the manufacturer’s guarantee, so be sure to check in your user manual.

It’s possible that your insurer will refuse to pay out if the wrong tyres have been selected, or that a police officer will fine you for having unsafe tyres. In the worst cases, the wrong speed rating can cause a tyre blowout or serious accident.

To ensure that you’re buying high-quality tyres, look out for ones that are labelled with EU tyre labels. These provide improved tyre information for buyers through a rating system that covers fuel efficiency, braking distance in wet conditions and exterior noise, making tyres with these labels ideal for long-distance motorists.

How to read the tyre speed index

The tyre speed index is a system that indicates the maximum speed that your tyre is legally approved for. The system is based on a lettered code and each letter corresponds to a speed. The tyre speed rating is clearly displayed on the sidewall of each tyre and indicates the fastest speed that a driver should not exceed when their vehicle is fitted with those specific tyres. The speed rating numbering system run from A1 to A8 in sequence, whilst the letters run from B to Y.

For example, a tyre that reads 255/40 R20 101V shows V to be the tyre speed rating. The tyre speed rating chart below shows that V corresponds to 149 mph. Therefore, tyres with this speed rating should not be driven over 149mph.

Tyre speed rating chart

What tyre speed rating do I need?

Most vehicles fit into the speed rating of S or T for 112 or 118 miles per hour limits (180 or 190 kilometres per hour). The speed ratings for wide diameter tyres are often higher as they are usually fitted to higher-performance vehicles. Sports cars need tyres with speed ratings of W, Y or (Y).

If you decide to choose tyres that are an incorrect speed rating, load index or size for your car, you must inform your insurance company, as it is likely to affect what you are entitled to claim in the event of an accident. At Tyre Shopper, we recommend that you keep speed rating in mind when choosing new tyres.

Use our Tyre Size or Registration search tool to find tyres that match your car perfectly.

How do I know the speed rating of my tyres?

To find the speed rating of your current tyres, simply look on the tyre sidewall. You’ll find the speed rating after the load index rating, and it will be one letter. For example, your tyre may have the letter ‘W’ as its speed rating, meaning it can go up to 168mph.

You can also find your tyre information in your car's handbook. You may also be able to find your tyre information on the inside of the fuel cover door or the inside of the passenger door.

Does tyre speed rating matter?

Yes, one of the most important parts of the tyre is its speed rating. If a tyre has the wrong speed rating for the vehicle then the tyre may wear faster, in turn causing a loss in fuel efficiency. If a tyre wears quicker than expected, this could cause many safety issues, including a loss of grip.

What does the load rating on tyres mean?

The tyre load rating is the maximum load capacity that a tyre can carry. This means the amount of weight a tyre can carry whilst driving. It is crucial to have the correct tyre load ratings for tyres on your vehicle as if the load rating is below what is recommended, your tyres may not be able to hold the weight of your car.

This could lead to the tyres wearing faster, less grip from the tyres, and overall compromise the safety of your vehicle. Therefore, it is crucial to get the correct tyre load rating for your vehicle. For a complete guide on tyre load rating, including a tyre load rating chart, click the link below.

Tyre Load Rating

Expert advice

Here at Tyre Shopper, our staff can help you meet your exact requirements when you need to buy car tyres. We stock many tyre brands which help our technicians to offer the widest selection of tyre choices to suit every vehicle. These tyres come at the lowest possible price online. See our price promise to see how we beat any competitors.