Tires: Service Precautions

TIRE CONDITION/TIRE PRESSURE
Tires are a safety component and can only fulfil the requirements imposed on them when the air pressure is correct and there is sufficient depth of tread.

The stated tire pressures are minimum values below which tire pressures must never fall. Besides the adverse effect on driving behavior, there would be a risk of severe tire damage.

Valve caps protect the valve from dust and dirt and thus from leaks. Always screw caps tight and replace any missing caps.

For reasons of safety, besides a check on air pressure a visual check should be made for sufficient tread depth, foreign bodies, punctures, cuts, cracks and bulges in the sidewall (ply breakage).

TIRE AGE
High-speed ZR tires in particular should not be too old - never older than 6 years. The age of the tire can be determined via the manufacturer's code, which is listed behind the DOT code on the tire sidewall. The date of manufacture (the last three digits) is located at the end of the code. For the years 1990 to 1999, the 3-digit code is sometimes supplemented by "triangle suffix" (Distinguishing feature.)
Example:
DOT DM CP 05 Y 065
06 = Production week 6
5 = Production year 1995

TIRE DAMAGE/REPAIRS
Repairs on "ZR" tires is not allowed, as is the use of inner tubes in tubeless tires.

If a tire is damaged and it cannot be determined with absolute certainty that there is no ply damage - with all of its consequences - or if the tire was thermally or mechanically overloaded due to a loss of pressure or other prior damage, we recommend replacement of the tire in question for safety reasons.

TIRE MATCHING ON REPLACEMENT
If new tires are to be mounted or the tires of one axle are to be replaced, tires of the same make and with the same specification code must always be used on each of the two axles. If tires are replaced on one axle only, the different tread depth than on the other axle can cause a noticeable change in the familiar handling. This is especially the case if new tires are mounted on the rear axle. This effect decreases with increasing tire mileage.

When replacing a tire on an axle, make sure that the tread depth of the new tire does not differ from that of the other tire by more than 30%.