Tyres used on cars feature something known as a speed rating. In this guide, we explain what exactly a tyre speed rating is and how you can make sense out of them.
Tyre speed rating explained
The tyre speed rating indicates the maximum speed a tyre is legally approved to travel at.
It is useful information as it allows drivers to know the quickest they can safely travel in their vehicle.
Tyre speed ratings are determined through tests conducted by engineers who run the tyre they’re assessing at 6.2mph steps, in ten minute increments, until the required speed has been met.
Wider, larger-diameter tyres tend to have the highest speed ratings and such tyres are usually found on high-performance cars, including hot hatches, roadsters and supercars.
How to read a tyre
You can work out the exact tyre speed rating that has been given for the tyres on your car by looking at the side profile of one of the tyres and reading the relevant label.
On the tyre’s sidewall, next to the numbers which indicate the size of the tyre (which will read as something like 225/45R17, for example), there will be a separate two-digit figure with a letter right next to this. While the two-digit number explains what is known as the ‘load index’, the letter next to this is the speed rating.
This letter on the tyre’s sidewall reveals the maximum speed the tyre can travel to, but knowing what exactly the letter means requires being clued up on the different tyre speed ratings.
Tyre speed rating chart
Different letters are used on tyres to designate what the maximum speed they can legally and safely travel on is.
Listed below are the different letters used for tyre sidewalls and the specific top speeds associated with them. The ordering is somewhat confusing as the maximum speed tends to increase as you progress through the alphabet but there are some exceptions. For example, tyres with the speed rating ‘U’ can travel faster than those marked ‘T’, but not tyres marked ‘H’.
Tyre speed ratings
N – 87mph
P – 93mph
Q – 99mph
R – 106mph
S – 112mph
T – 118mph
U – 124mph
H – 130mph
V – 149mph
Z – 150+mph
W – 168mph
Y – 186mph
