The markings and writing on your tyre not only state the brand and model of the tyre, but also the sizes, width, aspect ratio, and load and speed rating.
But what does that mean? Putting the branding to one side, let’s focus on the numbers and letters.
For example, a tyre may say 205/65/R16 . This would mean that the tyre is 205 mm wide, the 65 is an aspect ratio. This ratio is what the height of the tyre sidewall is, in relation to its width. So in this example, the tyre wall is 65% of the tyres width.
Next is R16 , which tells us two things, the ‘R’ , that the tyre is of radial construction, the 16 tells us what diameter wheel these tyres are designed for.
So this tyre is telling us it’s a radial tyre, 205 mm wide, with a tyre wall 65% of its width, which will only fit 16 inch wheels.
The next two sets of numbers and letter are the load index, and speed rating. So if we use the same 205/65/R16 tyre, we now see a number and a letter.
The number is the load index, this tells us the weight that each tyre can carry, the letter is the speed rating, denoting what maximum speed the tyre can safely drive at.
So from the example, we see that this tyre has been rated 95 V . From the charts below we can see that this tyre is rated to carry no more than 690 KG per wheel. So a total vehicle weight of 2760 KG ( the average vehicle weight being about 1,400KG ) is permitted. The speed rating on the example tyre V, means that it is not recommended by the manufacturer to exceed 150mph.
These ratings may seem high but they need to accommodate unrestricted roads such as the Isle of Man and the German Autobahns.