Front axle

20-inch summer tires

2.0 bar
(29 psi)

20-inch summer tires
Cup 2R

2.2 bar
(32 psi)

21-inch summer tires

2.3 bar
(33 psi)

21-inch summer tires
Cup 2R

2.5 bar
(36 psi)

20-inch winter/all-season
tires
Sizes:

Rear axle

2.3 bar
(33 psi)

2.5 bar
(36 psi)

Permissible wheel and tire sizes
(RO = rim offset in mm, FA = front axle, RA = rear axle)
Tires

Tire sizes

Wheel sizes

Snow
chains

911 GT2 RS/GT3 RS
Summer

FA: 265/35 ZR 20 99 XL Y
RA: 325/30 ZR 21 108 XL Y

FA: 9.5 J x 20 H2, RO 50
RA: 12.5 J x 21 H2, RO 48

Winter

FA: 245/35 R 20 91 V M+S
RA: 315/35 R 20 110 XL V M+S

FA: 9J x 20 H2, RO 55
RA: 12J x 20 H2, RO 47

No
RA only

911 GT3/Touring/GT Speedster

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Summer

FA: 245/35 ZR 20 95 XL Y
RA: 305/30 ZR 20 103 XL Y

FA: 9 J x 20, RO 55
RA: 12J x 20, RO 47

No

Winter

FA: 245/35 R 20 91 V M+S
RA: 295/30 R 20 97V/101 XL V M+S

FA: 9 J x 20, RO 51
RA: 11J x 20, RO 59

RA only

AfterSales

911 (991)

Technical Information
Wheels:

10/19

ENU

4400

4

Overview of Porsche wheels for summer and winter tires
Identification on the inside/outside of the wheel disc:
Wheel size, rim offset (RO) in mm, Part No. (FFF = color code) and Porsche logo
911 GT2 RS

20, 21-inch GT2RS aluminum wheel with
central lock
FA: 9.5 J x 20 H2, RO 50
Part No. 991.362.162.83 FFF
RA: 12.5 J x 21 H2, RO 48
Part No. 991.362.167.84 FFF

20, 21-inch GT2RS aluminum wheel

20, 21-inch GT2RS magnesium wheel with
central lock
FA: 9.5 J x 20 H2, RO 50
Part No. 991.362.163.83 FFF
RA: 12.5 J x 21 H2, RO 48
Part No. 991.362.168.84 FFF

20, 21-inch GT2RS magnesium wheel

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Technical Information

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911 GT3 RS

20, 21-inch GT3RS aluminum wheel with
central lock
FA: 9.5 J x 20 H2, RO 50
Part No. 991.362.162.84 FFF
RA: 12.5 J x 21 H2, RO 48
Part No. 991.362.167.85 FFF

20, 21-inch GT3RS aluminium wheel

20, 21-inch GT3RS magnesium wheel with
central lock
FA: 9.5 J x 20 H2, RO 50
Part No. 991.362.163.83 FFF
RA: 12.5 J x 21 H2, RO 48
Part No. 991.362.168.84 FFF

20, 21-inch GT3RS magnesium wheel

Information
Improper handling can damage the wheel surface.
Carry out tire removal and mounting using a bead holding-down device only.
Use a leather pad on the rim flange to support the valve insertion tool.
Only use the Porsche centering clamping set for balancing.
Do not use brushes to clean the wheels because brushes can cause deep scratches that cannot be
removed by polishing.
Never use solvents or other chemical substances on tires.
Wheel
Mounting:

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using central wheel lock:
Tightening torque 600 Nm (444 ftlb.)

AfterSales

911 (991)

Technical Information

10/19

ENU

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WARNING
Incorrectly installed snow chains
•

Uncontrollable vehicle handling



Do not exceed the maximum speed of Speed 30 mph/50 km/h.



Observe installation instructions from the chain manufacturer.

Snow Chains:

Porsche offers the following snow chains as accessories:
Tire size

Porsche Part No.

Type of snow chain

991.044.601.00

Link-type chain, quick fit

911 GT2 RS/GT3 RS
315/35 R 20 M+S

Wheel Storage: Tires must be stored in a cool, dry and dark room with adequate ventilation. Tires must never come into
contact with fuel, oil, grease or chemicals. Do not store summer tires in storage areas with ambient
temperatures of less than 5° F (-15° C).
Complete wheels can be stacked for storage; we recommend that you increase the tire pressure by
approx. 6 psi (0.4 bar).
Optimum conditions for storage of the complete wheels are provided by the Original Porsche storage
trolley, Part No. 000.044.000.38.
If the tires are not mounted on wheels, it is best to store them in a vertical position. We recommend that
you turn tires stored in this position every two weeks in order to prevent flat spots. Tires that are stacked
in a horizontal position will become severely deformed and cannot be seated properly in the rim flange
when they are mounted.
General
Information:

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 on page 1 (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

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Technical Information

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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 permissible, 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.

Important Notice: Technical Bulletins issued by Porsche Cars North America, Inc. are intended only for use by professional automotive technicians who have attended Porsche service training
courses. They are written to inform those technicians of conditions that may occur on some Porsche vehicles, or to provide information that could assist in the proper servicing of a vehicle. Porsche special
tools may be necessary in order to perform certain operations identified in these bulletins. Use of tools and procedures other than those Porsche recommends in these bulletins may be detrimental to the
safe operation of your vehicle, and may endanger the people working on it. Properly trained Porsche technicians have the equipment, tools, safety instructions, and know-how to do the job properly and
safely. Part numbers listed in these bulletins are for reference only. The work procedures updated electronically in the Porsche PIWIS diagnostic and testing device take precedence and, in the event of a
discrepancy, the work procedures in the PIWIS Tester are the ones that must be followed.

© 2019 Porsche Cars North America, Inc.

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AfterSales