No. 32-21

911 (991)
Manufacturer's Certificate
32/21
ENU
4400
4
Approved Wheels and Tires (32/21)
Revision:
This bulletin replaces bulletin Group 23/18, dated November 19, 2018.
Model Year:
As of 2014 up to 2016
Vehicle Type:
911 Turbo (991)/911 Turbo S (991)
Information:
Approval status: May 2021
WARNING
Driving with different tires (mixed tires)
•
Uncontrollable vehicle handling

Only use tires of the same make and type, with the same speed index and the same specification code
(N0, N1, N2, ...) on a vehicle.
Summer Tires:
Model
Tire size
Tire make and type/
label value (link to EU database)
911 Turbo,
911 Turbo S
245/35 ZR 20 (91Y) XL
and
305/30 ZR 20 (103Y)
XL
Pirelli P-Zero N1
(Inside/Outside)
245/35 ZR 20 (95Y)
and
305/30 ZR 20 (103Y)
XL
Michelin Pilot Sport 4S N0
(Inside/Outside)
FA: https://eprel.ec.europa.eu/qr/595261
RA: https://eprel.ec.europa.eu/qr/595262
FA: https://eprel.ec.europa.eu/qr/411317
RA: https://eprel.ec.europa.eu/qr/408604
WARNING
Driving with sports tires
•
Aquaplaning on wet or muddy roads

Reduce speed.

Drive according to the road conditions.
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Jun 17, 2021
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911 (991)
4400
Summer Tires
(UHP):
ENU
Manufacturer's Certificate
32/21
Model
Tire size
Tire make and type/
label value (link to EU database)
911 Turbo,
911 Turbo S
245/35 ZR 20 (91Y)
and
305/30 ZR 20 (103Y)
XL
Dunlop Sport Maxx Race N0
(Inside/Outside)
FA/RA: Data currently not available
Pirelli P Zero Corsa N0
(Inside/Outside)
FA: https://eprel.ec.europa.eu/qr/595261
RA: https://eprel.ec.europa.eu/qr/595262
Information
Sports tires (Ultra High Performance Tires) are permitted on public roads and satisfy all legal
requirements and road safety criteria.
These tires are also designed for use on racing circuits (driving safety training courses, sports driving
schools, Clubsport events) and offer distinct advantages with regard to dry adhesion and wear-and-tear
compared to normal road tires.
The main features are a reduced tread depth as well as a special thread design and substructure.
Winter Tires:
Model
Tire size
Tire make and type/
label value (link to EU database)
911 Turbo,
911 Turbo S
245/35 R 20 91V
M+S and
295/30 R 20
101V M+S
Michelin Pilot Alpin PA4 N0
(Rotation)
FA: https://eprel.ec.europa.eu/qr/412844
RA: https://eprel.ec.europa.eu/qr/411498
Pirelli Winter 240 Sottozero Serie II N0
(Inside/Outside)
FA: https://eprel.ec.europa.eu/qr/594297
RA: https://eprel.ec.europa.eu/qr/594293
Information
N... = Specification code of the tire, e.g. "N0", "N1", "N2" ... The complete "N ..." code of the tires in
question must be shown on the tire sidewall near the tire type designation.
Instructions for correct mounting of the tires are also given on the tire sidewall. If there are no mounting
instructions on the tire sidewall, the tire must be mounted so that the DOT marking is visible from the
outside.
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AfterSales
911 (991)
Manufacturer's Certificate
32/21
ENU
4400
Arrow with inscription "Rotation"
= directional mounting
“Inside/Outside” inscription or “Left” or “Right”
= mounting on specified side only
Arrow with both inscriptions "Rotation" and
"Inside/Outside"
= directional mounting on specified side only.
Arrow with both inscriptions “Rotation” and “Left”
or “Right”
= directional mounting on specified side only.
4
Information
If a tire is damaged and it is not possible to determine with absolute certainty that there is no ply damage
- with all of its consequences - or if the tire was thermally and/or mechanically overloaded due to a loss of
pressure or other prior damage, replace the tire in question for safety reasons.
Repairs to "V", "W", "Y" and "ZR" tires are not permissable, as well as the use of inner tubes in tubeless
tires. Please inform your customers accordingly. It is advisable to mount winter tires at temperatures
below 45° F/7°C , because the driving characteristics of summer tires are reduced at low temperatures.
Extremely low temperatures can cause permanent damage to summer tires.
WARNING
Incorrect tire pressure
•
Uncontrollable vehicle handling

Adjust the tire pressure according to specifications. Never allow the pressure to fall below the minimum
pressure.

Check age of tires. Replace tires that are more than 6 years old.

Perform visual inspections.

Use only tires recommended by Porsche.
WARNING
Driving at high speed with low tire pressure can cause irreparable damage to tires.

Set Comfort air pressure for tires only on vehicles with Tire Pressure Monitoring System (TPMS) and
“Comfort” selected in the "Tire pressure" main menu in the multi-function display.
Tire Pressure:
Information
The 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.
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911 (991)
4400
ENU
Manufacturer's Certificate
32/21
Standard tire pressure for summer tires
Part load
Wheel size
20-inch wheels
Full load
FA
RA
FA
RA
2.4 bar
(34 psi)
3.0 bar
(43 psi)
2.6 bar
(37 psi)
3.3 bar
(47 psi)
Standard tire pressure for winter tires
Part load
Wheel size
20-inch wheels
Full load
FA
RA
FA
RA
2.2 bar
(31 psi)
2.7 bar
(39 psi)
2.4 bar
(34 psi)
3.0 bar
(43 psi)
Comfort tire pressure for summer tires up to 270 km/h (165 mph) – only for vehicles with
Tire Pressure Monitoring (TPM) and “Comfort pressure” menu in the multi-function display
(depending on the country)
Part load
Wheel size
20-inch wheels
Sizes:
Full load
FA
RA
FA
RA
2.2 bar
(31 psi)
2.5 bar
(36 psi)
2.3 bar
(33 psi)
2.8 bar
(40 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 Turbo, 911 Turbo S
Summer
FA: 245/35 ZR 20 (91Y)
RA: 305/30 ZR 20 (103Y) XL
FA: 8.5 J x 20 H2, RO 51
RA: 11 J x 20 H2, RO 56
No
FA: 8.5 J x 20 H2, RO 51
RA: 11 J x 20 H2, RO 59
No
FA: 9 J x 20 H2, RO 51
RA: 11.5 J x 20 H2, RO 56
No
- Not for Japan
Winter
Jun 17, 2021
Page 4 of 9
FA: 245/35 R 20 91V M+S
RA: 295/30 R 20 97V M+S
AfterSales
FA: 8.5 J x 20 H2, RO 51
RA: 11 J x 20 H2, RO 56
RA only
FA: 8.5 J x 20 H2, RO 51
RA: 11 J x 20 H2, RO 59
RA only
911 (991)
Manufacturer's Certificate
32/21
ENU
4400
4
The following wheel/tire combination is also permitted for 911 Turbo vehicles:
Tires
Tire sizes
Wheel sizes
FA: 245/35 R 20 91V M+S
RA: 295/30 R 20 97V M+S
FA: 8.5 J x 20 H2, RO 51
RA: 11 J x 20 H2, RO 52
Snow
chains
911 Turbo
Winter
– Not for vehicles with Porsche
Ceramic Composite Brake
(PCCB)
Wheels:
No
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 number (without color code FFF) and Porsche logo
20-inch 911 Turbo III wheel
(5-hole bolting system)
Front: 8.5 J x 20 H2, RO 51
Part No. 991.362.161.06 FFF
Rear: 11 J x 20 H2, RO 56
Part No. 991.362.166.09 FFF
20-inch 911 Turbo S wheel
(central lock)
Front: 8.5 J x 20 H2, RO 51
Part No. 991.362.161.34 FFF
Rear: 11 J x 20 H2, RO 59
Part No. 991.362.166.34 FFF
or
Front: 9 J x 20 H2, RO 51
Part No. 991.362.162.34 FFF
Rear: 11.5 J x 20 H2, RO 56
Part No. 991.362.167.34 FFF
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911 (991)
4400
ENU
Manufacturer's Certificate
32/21
20-inch Sport Classic II wheel
(5-hole bolting system)
Front: 9 J x 20 H2, RO 51
Part No. 991.362.162.41 FFF
Rear: 11.5 J x 20 H2, RO 56
Part No. 991.362.167.42 FFF
20-inch Carrera S III wheel
(5-hole bolting system, winter tires only)
Front: 8.5 J x 20 H2, RO 51
Part No. 991.362.161.04/.40 FFF
Rear: 11 J x 20 H2, RO 52
Part No. 991.362.166.05/.41 FFF
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:
using wheel bolts:
Tightening torque 160 Nm (118 ftlb.)
using central wheel lock:
Tightening torque 600 Nm (444 ftlb.)
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AfterSales
911 (991)
Manufacturer's Certificate
32/21
ENU
4400
4
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:
Wheel Storage: •
•
•
•
•
•
•
•
General
Information:
•
•
•
•
•
Tire size
Porsche Part No.
Type of snow chain
295/30 R 20 M+S
991.044.600.00
Link-type chain, quick fit
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 wheel & tire assemblies can be stacked for storage; we recommend that you increase the
tire pressure by approximately 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.
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.
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).
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911 (991)
4400
ENU
Manufacturer's Certificate
32/21
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.
New Tires (Replacements):
•
•
•
•
If new tires are to be mounted or the tires of one axle are to be replaced, tires of the same make,
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 on the same axle by more than 30 %.
Refer to WM 449503 for specific details of the vehicle you are working on.
•
•
>The 2mm specification will be given here.
> If there is none listed then the default is 30%.
Repairs to 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.
Repairs to "V", "W", "Y" and "ZR" tires are not permissible, as is the use of inner tubes in tubeless tires.
Tire Aging:
•
•
•
•
•
•
•
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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.
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911 (991)
Manufacturer's Certificate
32/21
ENU
4400
4
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.
© 2021 Porsche Cars North America, Inc.
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