Tyre-Speed Ratings | They Can Be Pretty Confusing!

If you’re an avid car enthusiast who likes to read into the technical stuff, then I’m sure you’re already gobsmacked by the weird ways tyres are rated. X, Y, Z - what the hell!

So lets get this one over with once and for all..

These alphabetical ratings are basically speed ratings that indicate what speeds the tyre can achieve safely. A one letter difference in the speed rating can mean an upto 10kmph increase in the rating. These ratings are given after a testing process which consists of the tyre running at 10kmph steps in 10 minute increments until the required speed has been met.

Wider, larger-diameter tyres frequently have a higher speed rating since they are commonly installed on more capable cars and are therefore made to withstand higher speeds. Y is the highest letter used to denote the speed rating. The speed rating is displayed on the tyre’s sidewall, after the load rating. As you can see from the table below, there are a few outliers since automakers have increased the top speeds of their vehicles and new speed ratings have been established to reflect those changes.

These ratings are not only used for speeds. They’re also about ride comfort, traction, tread wear and cornering ability. A higher speed rating generally offers better grip and stopping power, but it may have a lower tread life and reduced performance in cold weather. That’s why V, Z, W and Y-rated tyres are usually better suited to high performance vehicles in warmer climates.

You can increase the speed rating of your vehicle’s tyres for improved performance, but can never decrease it without reducing the vehicle’s top speed to that of the lower speed rating selected.

Words: Sresht Garg