What does speed rating mean?
The speed rating of a tyre is displayed on the sidewall. You will find it at the end of the tyre's size. It is always represented by a letter - in the following example the tyre speed rating is "V".
Tyre speed ratings are based on tests in which engineers run the tyre at 6.2 mph steps, in 10 minute increments, until the required speed has been met.
Why is the tyre speed rating important?
The faster you are travelling, the faster your wheels and tyres rotate. This can create a lot of heat as the speed increases. This is why choosing tyres with the correct speed ratings according to your vehicle is very important. To ensure they have been designed for the suitable usage.
Does speed rating matter on tyres?
Yes, speed rating is an important factor when selecting tyres. Choosing a tyre with a speed rating that is too low for your vehicle can be dangerous. It is essential to select a tyre with a speed rating that is at least as high as the maximum recommended by the car manufacturer.
How To Read Tyre Speed Ratings
Tyre speed ratings are typically represented by a letter code that appears after the tyre size. The most common speed ratings are:
• Q - up to 160 Kmh
• S - up to 180 Kmh
• T - up to 190 Kmh
• H - up to 210 Kmh
• V - up to 240 Kmh
• W - up to 270 Kmh
• Y - up to 300 Kmh
Tyre speed ratings should not be confused with load rating – this tells the driver the maximum weight the tyre can safely carry.
What happens if you go faster than the speed rating?
Exceeding the speed rating of your tyres can be dangerous, as it can cause the tyres to overheat and fail.
This can result in a loss of control of the vehicle and potentially catastrophic accidents.
However, in New Zealand with the maximum speed limit being 110KMH, this should not be an issue. As nearly all speed ratings are in excess of this law. So no-one should be driving at speeds too high for the tyre.
What difference does tyre speed rating make?
Despite the name, the speed ratings are not only about speed. The speed rating also gives an indication as to the tyre's comfort levels, rate of wear, traction, and performance when cornering.
For example, tyres which have been developed to produce a high speed rating are generally better equipped to deliver greater grip and braking - however their durability and winter weather performance may not be as strong as tyres with a lower speed rating.
Tyre Speed Rating Table
The following is a table which notes each car tyre speed rating and the the maximum speed each rating: