Tires/Wheels - Summer Applications
911 (997)5/05
Section - Group 4, Running Gear
This bulletin replaces Bulletin Group 4, # 1/04, dated 7-25-04
Overview of Summer Tires, Wheels & Spacer Rings
Vehicle Type:
911 Carrera (997)/911 Carrera S (997)
Model Year:
As of 2005 (5)
Concerns:
Summer tires and wheels - status 6/2005
Information:
Approved summer tire makes and types.
Installation Notes:
Instructions for correct mounting of the tires are also given on the tire sidewall as shown.
If there are no mounting instructions on the tire, the tire must be mounted so that the DOT code is visible from the outside.
Danger!
Increased risk of accident due to low tire pressure and/or insufficient maintenance.
> The tire pressure must never fall below the specified tire pressure.
> Check the tires at regular intervals for uniform profile wear and for possible damage such as cracks, bulges, detachments in the running surface, penetration by foreign objects, etc..
> Tires older than 6 years are to be replaced.
> Never use solvents or other chemical substances on tires (e.g. for cleaning or dying)
> Replaced rubber tire valves at every tire change.
Tire Pressure
The 911 Carrera (997) and 911 Carrera S (997) have no spare tire, instead they come equipped with a tire sealant system.
This tire pressure applies only to the tire makes and types approved by Porsche, and is specified for cold tires (approx. 68°F /20°C). The tire pressures must never be lower than the specified values.
Sizes:
Permissible summer tires and wheels.
Caution!
Risk of surface damage if the tires/valves are not mounted according to regulations, and/or if the wheel surface is not cleaned/cared for correctly.
> Carry out tire removal and mounting with a bead holding-down device only.
> Use a leather pad on the rim flange to support the valve insertion tool.
> Use only the Porsche centering clamping set for balancing.
> Do not clean the wheels with brushes (speak to car wash operator).
> Deep scratches in the surface coating of the wheel cannot be repaired by polishing.
Wheels:
Overview of Porsche wheels for summer tires
Wheel Mounting:
Tightening torque: 130 Nm (96 ft-lb.)
Navigation System:
After a wheel change, the full locating accuracy is attained only after a trip of approx. 30 miles (50 km) (if possible on the highway and at a speed > 38 mph (60 km/h). Additionally, high slip of the wheels (e.g. wheel spin on snow) can result in temporary incorrect positioning.
General:
Always use new valves when changing tires.
Always observe any possible instructions concerning the rolling direction and/or specifying which side the tires must be mounted on. Refer to notes (if applicable).
Coat the tire beads and humps with mounting lubricant before mounting the tire. This ensures that the tire beads will slide over the humps easily. In order to prevent the tire from turning on the wheel, avoid extreme driving maneuvers (acceleration and braking) during the first (100 to 200 miles) with new or recently mounted tires.
In order to optimize smoothness of rolling, it is appropriate - and necessary in individual cases - to mount the tire in a certain (favorable) position with respect to the wheel (matching). Matching (uncontrolled and controlled) is explained below:
Uncontrolled matching:
Turning the tire on the wheel by 90° or 120° if necessary in order to achieve an acceptable value with regard to rolling smoothness (true running, imbalance and weight distribution of balance weights).
Controlled matching:
With a balancing machine with matching program. In most cases, this produces an even better result with regard to the rolling smoothness (true running, imbalance and weight distribution of the balance weights) than can be achieved with uncontrolled matching. Maximum permissible radial runout and lateral runout of the wheels < 0.7 mm. Maximum permissible radial runout and lateral runout of the wheels with tires < 1.25 mm. Values < 1.50 mm - ideally approx. 0.5 mm - are desirable.
The mounting pressure (seating pressure) of 58 psi/4.0 bar overpressure must not be exceeded before both tire beads are evenly seated on the rim flange.
If new tires are to be mounted or the tires of one axle are to be replaced, tires of the same make, the same type 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 from that 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 %.
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.
Repairs on "ZR" tires are not allowed, as is the use of inner tubes in tubeless tires. Tires age due to chemical and physical processes, which can impair their function. Tires that are stored unused for an extended period harden and become brittle faster than tires that are in continual use. Hairline aging cracks can occur on older tires. On tires in continual use, the kneading action activates the plasticizer in the rubber and thereby prevents hardening and cracking.
Therefore, attention should be paid not only to the tread depth but also to the age of the tire. Tires should not be older than 6 years. The age of the tire can be determined via the DOT code on the sidewall, which indicates the production date of the tire: e.g. DOT 2201=22nd week of 2001.
Tires/complete wheels must be stored in a cool, dry and dark room with adequate ventilation. They must never come into contact with fuel, oil, grease or chemicals.
Complete wheels can be stacked for storage; it is advisable to increase the tire pressure by 0.4 bar. Optimum conditions for proper storage of the complete wheels are provided by the Original Porsche storage stand (trolley), Part Number 000 044 000 38.
If the tires are not mounted on wheels, it is best to store them in vertical position. Tires stored in vertical position should be turned every two weeks in order to prevent excessive flattening. If the tires are stacked in horizontal position, they will become severely deformed and cannot be seated in the rim flange easily when they are mounted.
If the tires are not mounted on wheels, it is best to store them in a vertical position. In this case the tires should be turned every two weeks in order to prevent excessive flattening. If the tires are stacked in horizontal position, they will become severely deformed and cannot be seated in the rim flange easily when they are fitted.
Reference
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