Tyre Guide: What do the Numbers Mean?

If you’re buying new tyres for your car there’s plenty to consider. This tyre guide will help you identify the kind of tyre you’re buying and help you determine if it’s suitable for your car.

We’re all familiar with where the numbers on the tyres are but from left to right, they always denote the width, profile, build of tyre, rim size, load rating, and speed rating in that order.  

Here’s an example of a typical tyre: 205/55/R16 91H
– width = 205
– profile = 55
– build = R
– rim size = 16-inches
– load rating = 91
– speed rating = H

Width of the tyre

The width of the tyre affects the grip it has on the road. Faster cars need more grip so you the width will be similarly larger.

For an easy example, an F1 car has a tyre width of 305mm in the front wheels and 405mm in the rear. In comparison, the Honda City only has a width of 185mm.

It’s recommended you stick to the recommended width prescribed by the manufacturer.

Profile of the tyre

The profile number is a percentage of the total tyre sidewall height from total tyre width. In this case. 55% of 205mm.

The taller the tyres, the more cushion you might feel over bumps and the thinner they are, the more control you’ll feel while driving.

SUVs typically have taller tyres that absorb bumps at 60% while a souped up Mercedes-AMG GT 63 has a tyre profile of 35%. Great around the corners but you better brake before hitting that speed bump.

Build and rim size

The build is always R for radial in modern cars. There are others such as B for Bias belt and D for Diagonal, but these are for older cars.

The next number is the size of the rims appropriate for the tyre. Pretty self-explanatory. If you’re wondering, rims do not affect the performance of your car.

Load rating and speed rating

Think of these as movie ratings. The higher the load rating, the higher the load it can carry. A 91 load rating can carry 615kg. That’s for one tyre, so at 4 tyres, the total weight it can carry is 2,460kg.

A typical sedan weighs about 1,300kg so provided you aren’t transporting multiple walruses at a time, your tyres will be able to sustain most passengers and loads.

As for speed rating, there are arbitrary letters assigned to speeds. H in our example denotes a speed limit of 210km/h. Spare tyres might have an M rating or 130km/h and ultra performance sports cars might have tyres with a Y rating for speeds of up to 300km/h.

Looking for more guides? Read our guide on tyre pressure here.