Porsche Boxster Owner's Manual page 251

If you must drive over a curb or other obstacle,
drive slowly and at an obtuse angle. Exercise
care when parking along curbs.
Wheel alignment, wheel balancing
As a precaution, have wheels with summer
tires balanced in the spring, and those with
mud and snow tires before winter. Unbalanced
wheels may affect car handling and tire life. Only
the specified weights may be used for wheel
balancing. Self-adhesive weights must not come
into contact with cleaning agents, since they could
drop off. Uneven tread wear indicates wheel
imbalance. In this event, the vehicle should be
checked at an authorized Porsche dealer.
Warning!
If, during a trip, uneven running or vibrations
occur that could be caused by damage to
tires or the car, the speed must be reduced
immediately, but without braking sharply.
If you continue your trip without having the
cause of the fault remedied, you might lose
control of your vehicle which could cause
serious personal injury or death.
Stop the vehicle and check the tires.
If no cause for the fault can be found, drive
carefully to the nearest authorized Porsche
dealer.
Removing and storing tires
After changing, adjust tire pressure and torque
wheel bolts diagonally to 94 ft.lb. (130 Nm).
Tires must always remain on the same side
of the vehicle. When wheels are removed,
the direction of rotation and position of each
wheel should be marked.
Example
FR (front right), FL, RR and RL.
Wheels must always be fitted in accordance with
their marking.
The perception that tire durability and performance
are immune to the effects of storage and age
is unfounded. Chemical additives, which make
the rubber elastic, lose their effectiveness in the
course of time and the rubber becomes brittle and
cracks.
Therefore, the tires should be inspected from
time to time.
Note
Under no circumstances should tires older than 6
years be used on your Porsche.
The age of the tire can be obtained from the
"DOT" code number. If, for example, the last four
numbers read 0706, then the tire was produced in
the 7th week of 2006.
Store tires in a cool and dry place.
Practical Tips, Emergency Service
249