Porsche 2007 Cayenne Owner's Manual page 328

Speed code letter
The speed code letter indicates the maximum per-
missible speed for the tire.
This code letter is shown on the tire sidewall.
T = up to 118 mph (190 km/h)
H = up to 131 mph (210 km/h)
V = up to 150 mph (240 km/h)
W = up to 167 mph (270 km/h)
Y = up to 186 mph (300 km/h)
Tip on driving
Tires with a maximum speed rating that is lower
than the specified maximum vehicle speed may be
mounted only if they bear an M+S identification on
the tire sidewall.
f Please note that in addition to the winter tires,
all-season and all-terrain tires are also subject
to speed limits and bear this identification.
Inscription on light alloy wheels
Note on operation
f The rim width in inches G and the rim offset L
are visible from the outside. This information
can be found near the tire valve.
328
Minor Repairs
G - Rim width in inches
H - Rim-flange contour code letter
I - Symbol for drop-center rim
J - Rim diameter in inches
K - Double hump
L - Rim offset in mm