Ever wondered what the numbers on the side of your tyres mean?
Published Date: 9th Jun 2016
Setting about choosing new tyres for your car is more than just going for that brand that is advertised all the time on the TV. When purchasing new tyres today there is a large range of information that will help you to compare and choose the right tyre for you.
Most of this is displayed on the rubber sidewall of the tyre and the rest is shown on a label that was attached to the tyre.
The New Tyre Label Guide
The new tyre information label is mandatory with every new tyre sold in Europe. The label looks similar to when you buy a new home appliance and there is a power efficiency table. On the label is the tyres wet grip rating, fuel efficiency, and noise rating.
New Tyre Fuel Efficiency
The first column on the chart shows the fuel efficiency, based on the rolling resistance of the tyre from A to G. The difference between the top A and bottom rank G can be up to 7.5% according to research by the European Commission
New Tyre Wet Grip
The second column shows the grip rating on a wet road surface, using the same A to G rating. This is a trade off between rolling resistance, the lower friction between the tyre and road surface will also affect and reduce the grip in the rain, so you will always have to strike a balance between fuel consumption and wet grip.
The general rule is the wet grip determines the stopping distance from 50 mph. The difference between each grade is 1 to 2 car lengths. So the total stopping distance from A to G could be up to 18 metres.
The third chart at the bottom of the label shows the noise level. The amount of noise generated is measured when the car is travelling at 50mph in decibels (dB)
How do I read the tyre size and speed rating?
On the side or sidewall of every tyre is the size and speed rating and usually looks like this 215/45R16 91Y.
The First Three digits (215) show the width of the tyre in millimetres
The second two digits show the height of the sidewall or profile of the tyre in as a percentage to the width. So in this case the height of the sidewall is 45% of 215mm
The letter R refers to the construction of the plies (steel banding within) of the tyre and the R is for Radial construction
The next two numbers 16 refer to the rim size in inches. So this tyre will fit a wheel that is 16 inches in diameter
The following next two show the load rating of the tyre but don’t relate to the actual weight that the tyre can carry. So here we have 91 that means this tyre has the ability to carry 615Kg. Load ratings go from 62 (265Kg) to 126 (1,700Kg).
The next letter is the speed rating of the tyre in this case Y can go all the way up to 186mph. This rating denotes the maximum speed the tyre can maintain.
If you ever need to find the tyre size and speed rating for your car, it can be found in the owner’s manual.