Wheels & Tires - Summer Tire and Wheel Summary
911 (996)5/04
Binder - Group 4, Running Gear
This bulletin replaces several bulletins, see filing information below.
Summer Tire and Wheel Summary
Vehicle Type:
911 Carrera (996) and 911 Carrera 4 (996)
Model Year:
As of M. Y. 1999 (X)
Filing:
This bulletin replaces bulletins, Group 4, # 4/01, dated 11-30-01, # 4b/01, dated 3-5-03, # 9/01, dated 4-19-02, 9a/01, dated 4-19-02, and # 9b/01, dated 3-5-03. Remove all these bulletins from your Technical Manual.
Concern:
Summer tires, wheels, and spacer rings - status as of 04/2004
Information:
Approved Summer Tires and Types
Danger!
Increased risk of accident due to insufficient tire pressure and/or due to defective tires.
> 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.
Mounting Instructions:
Instructions for proper tire mounting are located on the tire sidewall.
Tire Pressures
Tire Sizes
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.
Reworking the Wing Seam:
The wing seam and if necessary the rear spoiler must be reworked in the areas shown (B).
A = transition approx. 50 mm
B = flange approx. 295 mm
C = transition approx. 25 mm
Caution!
Paint damage can occur in the event of improper reworking of the wing seam.
> Only carry out reworking when the wing seam is partially warmed.
> Partial painting is required if the conditions are unfavorable.
The wing seam must be flanged over a width of at least 10 mm and at least 60°; never flange grind or cut off more than 65°.
Adjusting the Rear Spoiler:
If the rear spoiler projects over the flanged rear side section (view A) the projecting part of the rear spoiler must be cut or ground off (arrow).
Spacer Ring/Wheel Installation:
The 5 mm thick spacer rings are mounted on the wheel hubs together with the brake discs using longer countersunk screws (M6x16), Part No. 900 269 106 09. Tightening torque: 10 Nm (7.5 ft-lb.).
The 5 mm spacer ring must remain on the vehicle when mounting the spare wheel.
Wheel mounting must take place with the 5 mm longer wheel bolts of the 911 GT3, Part No. 996 361 203 90. These GT3 wheel bolts are marked with GT or with a red color on the face surface (arrow) of the bolt head, or the rotating spherical cap ring is galvanized in red. Dimension X = approx. 50 mm. Tightening torque: 130 Nm (96 ft-lb).
The 17 mm spacer rings are mounted on the wheel hubs using the standard wheel bolts, Part No. 996 361 203 00/01 (dimension X = approx. 45 mm). Tightening torque: 130 Nm (96 ft-lb.).
The wheels are mounted on the 17 mm spacer rings using wheel nuts. Part Nos. 999 182 003 36. Tightening torque: 130 Nm (96 ft-lb.).
The 17 mm spacer ring must be removed when mounting the spare wheel.
Navigation Systems:
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:
Rubber valves, not for 18-inch Turbo I wheels, Part Number - 900 265 001 50 and 000 044 600 00. Steel valves, for 18-inch Turbo I and SportTechno wheels, Part Number - 993 361 073 00.
Always observe any possible instructions concerning the rolling direction and/or specifying which side the tires must be mounted on.
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.
Wheel Storage:
Tires must be stored in a cool, dry and dark room with adequate ventilation. They must never come into contact with fuel, oil, grease or other chemicals. Complete wheels can be stacked for storage: It is advisable to increase the tire pressure by 6 psi (0.4 bar).
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 installed.
Optimum conditions for proper storage of the complete wheels are provided by the Original Porsche storage stand (trolley), Part Number 000 044 000 22.
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