Tyre Speed Rating 101

by Kar Pro Tyres Auto Bridgestone Tyres

Tyre speed ratings are an essential part of tyre safety and performance. Just like load ratings, they are regulated by law. Driving a vehicle that has tyres with a lower speed rating than what is recommended is not only illegal, but it can affect the vehicle’s handling and steering.

Therefore, whether you’re buying Pirelli tyres or Cooper tyres for your car, you need to know the recommended speed rating.

What is Speed Rating?

Put simply; it’s the minimum standard for attaining and sustaining a specified speed; the higher the speed rating – the better the car handles as a result of better grip on the road and improved stopping power. However, it does mean that tread life is reduced.

Tyre speed ratings range from A to Y with A being the lowest and are determined by indoor lab tests under controlled conditions and measure durability at high speeds.

Can You Use Tyres with Lower Than the Recommended Rating?

This is not only illegal, but it’s dangerous too. Both handling and steering are affected if your vehicle is fitted with tyres that have a lower than recommended speed rating.

Can You Fit Tyres that Have a Higher Than Recommended Speed Rating?

According to a local mechanic in Campsie, it’s legal to fit tyres with a higher than recommended speed rating. In fact, it can also be beneficial as it improves cornering at higher speeds.

Can You Mix and Match Tyres with Different Speed Ratings?

It is possible to mix and match tyres with different speed ratings, although they should always be replaced in pairs. Each pair should be installed on the same axle with the lower speed-rated tyres on the front of the vehicle.

However, most manufacturers would recommend that you replace speed-rated tyres in sets of four. Your new tyres should have a speed rating equal to or greater than that of the original tyres. When tyres with different speed ratings are fitting, the overall speed rating will be equal to the lowest speed-rated tyre.

Tyres with a High Speed Rating

You may have heard of ZR tyres and wondered what they are. These are tyres that have a speed capability in excess of 240 kilometres per hour. In recent years, W and Y ratings have been issued for tyres that are able to cope with speeds of up to 300 kilometres per hour.

Choosing Your Speed Rating

All the details for choosing the correct replacement tyres can be found in your vehicle’s owner’s manual and also on the sticker on your driver’s side door, but if in doubt, contact your local tyre supplier or mechanic.