Tyre Size Guide

It is essential to make sure that your vechile's tyres are safe, as the consequences of having dangerous tyres are unthinkable. Not only are there safety fears, you could be faced with points on your license and a massive fine if your tyres are not up to scratch. Your insurance may also be worthless if you have an accident due to unsafe tyres, because it is your responsibility to maintain them. 

Below we have an example of how to check your tyre size which consists of 3 sets of numbers and a speed rating:

Leadgate Tyre Centre ImageWidth
This is the tyre width in millimetres

This is the ratio measurement of tyre width to profile height, shown as a percentage.

Wheel Size
This is the diameter of the inner rim in inches

Tyre Speed Rating

All tyres have a speed rating letter. The letter denotes a maximum speed that the tyre can sustain for a 10 minute period before becoming damaged. Each speed rating is 10Km/h above the previous.

As the table shows, the tyre speed rating is not considered vital due to the 70Mph speed limit imposed here in the UK.

Speed Symbol Approx MPH Approx KM/H
Q 99 160
R 106 170
S 112 180
T 118 190
H 131 210
V 149 240
VR 131 210
W 168 270
Y 186 300
ZR 149 240



It is also extremely important to make sure the tread of your tyre is at the legal limit of 1.6mm.

ROSPA (the Royal Society for the Prevention of Accidents) recommends that you should change your tyres when it reaches 3mm, which equates to your tyre being 78% worn.

The reason why this is so important is because the tread determines the distance your vehicle needs to stop. So if your tyres have an 8mm tread, they can stop in 25.9m in the wet. When your tyres are at the legal limit of 1.6mm, it will take 39.5m to stop in the same conditions at the same speed.

    8mm                                 Your Tyre is approx 0% worn
    7mm                                 Your Tyre is approx 15% worn
    6mm                                 Your Tyre is approx 31% worn
    5mm                                 Your Tyre is approx 47% worn
    4mm                                 Your Tyre is approx 62% worn
    3mm                                 Your Tyre is approx 78% worn
    2mm                                 Your Tyre is approx 94% worn
    1.6mm                        DANGER - Your Tyre is at the legal limit


                                       The current maximum fine is £2,500 and 3 Penalty Points per Tyre

Pressure Monitoring Systems

As of late Autumn 2012, all new cars must be fitted with tyre pressure monitoring systems (TPMS). The TPMS will be subject to testing during MOT's therefore must be tested and serviced to ensure they meet MOT standards.

Leadgate tyre centre now offer the service of testing and servicing the TPMS on all cars.

If you need any more information on the safety of your tyres, then contact one of our talented technicians on 01207 438155.

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