Tyre Designations - Chevrolet Corvette Owner's Manual

Caution
High performance summer tires
have rubber compounds that lose
flexibility and may develop
surface cracks in the tread area
at temperatures below -7 °C
(20 °F). Always store high
performance summer tires
indoors and at temperatures
above -7 °C (20 °F) when not in
use. If the tyres have been
subjected to -7°C (20°F) or less,
let them warm up for 24 hours or
more in a heated space to at least
5°C (40°F) for High Performance
Summer Tyres, or 10°C (50 °F)
for Competition Oriented Tyres,
before installing them or driving a
vehicle on which they are
installed. Do not apply heat or
blow heated air directly on the
tyres. While the cracking will not
result in air loss, it is damaging to
the tyre. Tyres that have been
used in cold climates and exhibit
(Continued)
Caution (Continued)
tread cracks should be discarded.
Always inspect tyres before use.
See Tyre Inspection 0 263.

Tyre Designations

E.g., 215/60 R 16 95 H
215 = Tyre width, mm
60 = Cross-section ratio (tyre height
to tyre width), %
R = Belt type: Radial
RF = Type: RunFlat
16 = Wheel diameter, inches
95 = Load index e.g., 95 is
equivalent to 690 kg
H = Speed code letter
Vehicle Care
Speed code letter:
Q = up to 160 km/h (100 mph)
S = up to 180 km/h (112 mph)
T = up to 190 km/h (118 mph)
H = up to 210 km/h (130 mph)
V = up to 240 km/h (150 mph)
W = up to 270 km/h (168 mph)
Y = up to 300 km/h (186 mph)
(Y)* = above 300 km/h (186 mph) -
consult the vehicle and tyre
manufacturer.
* The tyre should have ZR in the
tyre designation.
When the Y speed rating indicated
in a service description is enclosed
in parentheses, such as 285/
35ZR19 (99Y), the top speed of the
tyre has been tested in excess of
300 km/h (186 mph), indicated by
the service description as shown
below:
257