One way to keep on top of tyre safety is to make sure that the tyres on your car have the right tyre speed rating. We’ll explain what a tyre speed rating is, why it’s important and how to check it for your car.
In this article
What’s a tyre speed rating?
The speed rating of a tyre shows you the top speed that the tyre can safely be driven at. It’s a legally approved limit and tyres are only rated after they’ve been tested in a lab. The safest top speed applies as long as the tyre isn’t being driven with too much weight loaded.
Often, the tyre speed rating will be a faster speed than your car's able to go. That’s mainly for safety reasons, to make sure that you tyre performance is never worse than the car’s performance.
Does the tyre speed rating matter?
Choosing the right tyre speed rating for your car’s important for the safety of yourself and other road users.
If the tyre speed rating’s too low for your car, it might not be able to cope with the heat of high speeds. That could cause the tyre to lose performance and the car to lose control. It could even lead to a tyre blow-out.
But it’s not just about speed. The rating also relates to:
- Ride comfort
- Tread wear
- Cornering ability
It’s important to choose the right speed rating for your vehicle and the conditions. Tyres with higher speed ratings may give better grip and stopping distances, but they might not perform as well in the cold and could wear out faster.
Tyre speed rating and insurance
The tyre speed rating’s also important for legal reasons. If you have a lower tyre speed rating than you should, it might invalidate your car insurance.
Where can I find the tyre speed rating?
You can check the tyre speed rating on the sidewall of a car. There's a group of letters and numbers on the side. The final letter is the speed rating.
The speed rating letter comes after the load rating. It’s important to look at both together because the speed rating depends on driving with the right load.
Tyre speed rating chart
This chart shows you the maximum speed is for each tyre speed rating letter. The system is based on kilometres per hour (kmh), which is why the increments seem odd in miles per hour (mph).
Tyre load index chart
The 2 numbers on a tyre sidewall that come before the tyre speed rating are the load index. This shows you the maximum weight of the vehicle (and any load it’s carrying) for that tyre.
It’s important not to go over the maximum load as it could be dangerous. The tyre speed rating won’t be accurate and it could affect the way the tyres perform and handle.
You’ll also need to make sure your tyre pressure is correct.
|Load (kg)||Load index||Load (kg)||Load index||Load (kg)|
Can I fit tyres with a higher speed rating than I need?
Yes, you can. It’s not against the law to choose tyres with a higher speed rating that your car needs as long as they’re right for your vehicle.
Find out more about the legal requirements for car tyres.
Can I fit tyres with a lower speed rating that I need?
No, you shouldn’t ever fit tyres with a speed rating that’s too low for your car. It could cause steering and control issues or you might even suffer tyre failure.
It’s not illegal to use a tyre speed rating that’s too low but it is dangerous and it could stop your car insurance from paying out.
Can I mix tyres with different speed ratings?
We’d never recommended mixing tyres with different speed ratings on your vehicle.
It’s safest to fit the same size and type of tyre, with the same speed rating, on all your wheels.
Published: 23 November 2020 | Updated: 24 November 2020 | Author: The AA