Porsche Carrera GT, Manual

Page: 147 / 192

Practical Tips, Emergency Service
147
Temperature A, B, C
The temperature grades are A (the highest), B and
C, representing the tire’s resistance to the gener-
ation of heat and its ability to dissipate heat when
tested under controlled conditions on a specified
indoor laboratory test wheel.
Sustained high temperatures can cause the mate-
rial of the tire to degenerate and reduce tire life,
and excessive temperature can lead to sudden
tire failure.
The grade C corresponds to a level of perfor-
mance which all passenger car tires must meet
under the Federal Motor Vehicle Safety Standard
No. 109.
Grades B and A represent higher levels of perfor-
mance on the laboratory test wheel than the mini-
mum required by law.
Danger!
The temperature grade for this tire is established
for a tire that is properly inflated and not overload-
ed.
Excessive speed, underinflation, or excessive
loading, either separately or in combination, can
cause heat buildup and possible tire failure.
Tire pressures
Danger!
Incorrect tire pressure causes increased tire
wear and adversely affects road handling.
f Always use an accurate tire pressure gauge
when checking inflation pressures.
f Do not exceed the maximum tire pressure list-
ed on the tire sidewall.
Please observe the chapter “VEHICLE IDENTI-
FICATION, TECHNICAL DATA” on Page 177.
f Cold tire inflation pressure means: all tires
must be cold, ambient temperature maximum
68°F/20°C, when adjusting the inflation pres-
sure.
Avoid sunlight striking the tires before measur-
ing cold pressures, since the pressures would
rise from the temperature influence.
f Valve caps protect the valve from dust and dirt,
and thus from leakage.
Always screw caps tightly down.
Replace missing caps immediately.
f
Do not use commercially available sealant or
tire inflating bottles.
Tire traction
Danger!
When driving on wet or slushy roads, a
wedge of water may build up between the
tires and the road. This phenomenon is
known as “hydroplaning” and may cause par-
tial or complete loss of traction, vehicle
control or stopping ability.
f Reduce speed on wet surfaces to prevent this.
Tire life
Tire life depends on various factors, i. e., road
surfaces, traffic and weather conditions, driving
habits, type of tires and tire care.
f Inspect your tires for wear and damage before
driving off. If you notice uneven or substantial
wear, wheels might need alignment or tires
should be balanced or replaced.
f f f