McLaren Super Series Owner's Handbook Manual page 260

Maintaining Your McLaren
Wheels and Tyres
Tyre markings
1. Width of tyre in millimetres.
2. Tyre profile given as percentage of tyre
width.
3. Indicates that the tyre is radial ply.
4. Indicates the diameter of the wheel rim in
inches.
5. The numbers denote load index and the
letter indicates the speed rating. 91
indicates a weight of 615 kg (1,350 lbs) and
Y indicates speeds over 186 mph (300
km/h).
6.36
6. Displays the maximum load which can be
carried by the tyre.
7. Treadwear grade number. The higher the
figure the longer a tyre will last.
8. The alpha character denotes resistance to
heat. An 'A rated tyre offers most heat
resistance.
9. Information about the manufacture of the
tyre. Contains place and date of
manufacture.
Tyres
WARNING: The tyres must be
mounted according to the labelling
on the tyre wall. The word 'OUTSIDE'
must be on the outer edge of the tyre
when it is fitted to the wheel or the
stability of the vehicle will be
adversely affected, especially at high
speeds.
Asymmetric tyres
Asymmetric tyres have a tread pattern that is
different from one side of the tread to the other.
This combination of tread offers better grip in
both wet and dry conditions.
The outer tread features a larger stiffer tread
pattern that aids with cornering stability. The
inner tread pattern aids stability in wet
conditions. A central groove in the tyre aids
straight line stability.
WARNING: Only tyres recommended
by McLaren are to be fitted to the
vehicle.