Should I wait until a tyre reaches 1.6mm of depth before I change it?
A tyre is a lot less effective in the wet when below 3mm of tread depth remaining.
Under 3mm of tread depth, the tyre is less able to disperse water quick enough to avoid aquaplaning or loss of control. We advise replacing tyres if under 3mm of tread depth is remaining.
Tyre Size Information Before you order your new tyres, you will need to find out the size and specification appropriate for your vehicle.
The most accurate way to find this out is to check the vehicle itself.
It is important that you check the front and rear tyres as they can often be different in size.
A popular size for passenger cars is, for example:
205/55R16 91W Where:
‘205’ represents the approximate width of the tyre in millimeters
’55’ represents the sidewall height as a percentage of the width of the tyre – 55% of 205mm in this instance.
‘R’ represents the construction type – in this, as in almost all modern tyres, denotes a RADIAL construction
’16’ represents the diameter of the wheel measured in inches.
’91’ represents the load index (a reference chart detailing the maximum permissible weight the tyre can safely carry)
‘W’ represents the speed rating – in this instance a tyre with a manufacturers top speed rating of 168mph.
Speed Rating Information
The speed rating (denoted by a letter – ‘W’ in the example above) represents the maximum permissible speed for which the tyre is rated and indicates the speed at which the tyre can carry the load corresponding with its load index
You should replace your tyres with those of the same size, load and speed rating as recommended by the vehicles’ manufacturer.
Increasing the value of both the load and/or speed rating is acceptable practice but it is not recommended that lower value products be fitted.
The tyre should be able to withstand the forces applied to it at the vehicles maximum rated top speed.
There is currently no legal requirement for speed ratings but it is advised to check with your vehicle insurer of any potential issues that may arise when significantly altering specifications.
Speed Symbol Approx MPH
The load index is a numerical code, which corresponds to the maximum load a tyre can carry at the speed indicated by its speed symbol, under specific service conditions: