Tires/Wheels - Winter Tires and Chain Applications
911 (993)2/98
4440
Binder - Service Technical Bulletins
Date: 3-5-99
Winter Tires, Wheels and Snow Chain Applications
Vehicle Type:
911 Turbo (993), 911 Carrera S (993), 911 Carrera 45 (993)
Model Year:
Model Years 1995 - 1998, (S), (T), (V), (W)
Concern:
Approved Winter Tire Summary
Information:
Summer and winter tires have opposite, seasonal, and specific applications. This is particularly true for high performance Porsche vehicles equipped with wide "ZR" tires designed for safety on dry and wet roads.
The cold weather performance of summer tires is not adequate for winter conditions and their use is discouraged under those conditions.
Summer tires at temperatures below 50 Celsius (41° F) exhibit a decrease in their ability to adhere to the road surface. Installation of the approved winter tire/wheel combinations during cold weather conditions is strongly recommended.
Approved Winter Tires and Types
Inflation Pressures:
Valid for all tire sizes and types with the M+S profile:
17 Inch Wheels 18 inch Wheels
Front 2.5 bar (36 psi) Front 2.5 bar (36 psi)
Rear 2.5 bar (36 psi) Rear 3.0 bar (44 psi)
Front 3.0 bar (44 psi), Turbo with 225/45 R 17
The above tire pressures are valid only for tires approved by Porsche. The tire pressures must be checked and adjusted cold (approx. 20° C / 68° F). The values listed cannot be lower under any circumstance.
Tire Sizes:
Approved Winter Tires, Wheel Sizes and Spacer Ring Sizes
Wheels:
Overview of Porsche wheels for use with winter tires. The wheel description (wheel size, offset, part number and Porsche trademark (symbol) is indicated on the inside and outside of the wheel.
Wheel Fastening:
Secure the wheels to the hub with five (5) Porsche lug bolts M14 X 1.5 (19 mm socket size). Tightening torque 130 Nm (96 ft/lb).
Snow Chains:
The following snow chains are offered by Porsche as accessories:
Tire Size Porsche Part Number Snow Chain Type
225/45 R 17 996 361 920 00 Link-Type chain, quick fit
255/40 R 17 996 361 921 00 Link-Type chain, quick fit
Observe the tire chain installation instructions.
For safety reasons, snow chain equipped vehicles may not be operated at speeds above 30 mph (50 kmh). Always observe local laws and ordinances.
Information:
- Porsche recommended winter tires are exclusively "H" tires (210 kmh / 130 mph speed rating).
- At each tire change a new rubber valve stem (part number, 900 265 001 50 or 000 044 600 00, including cap) must be installed.
- During installation the notes on the tire sidewall regarding uni- or side-directional installation must be observed.
- Coat the tire bead and rim humps with assembly paste so that the bead easily glides over the hump. To avoid rotation of the new tire on its rim, hard acceleration or braking is to be avoided for the first 100 to 200 miles of driving.
- During tire mounting, the pressure in the tire should not exceed 4.0 bar (58 psi).
- When replacing a single tire on an axle, the difference in tread depth may not exceed 30%.
- Tires age from chemical and physical processes which can affect their function. Tires which are not driven for long periods of time harden and deteriorate faster than tires which are in continuous use. For this reason tires should be evaluated for both tread depth and aging. Tires should not be older than 6 years (including the spare). The tire age can be determined from the DOT description on the sidewall, which indicates the production date of the tire (example.: DOT ... 066, = 6th week of 1996).
- The storage area for tires must be cool, dry, dark, and ventilated. Tires must never come in contact with gasoline, oils, grease, or other chemicals.
- Complete tire/wheel assemblies can be stored horizontally. It is recommended that they be inflated 0.4 bar (6 psi) above the recommended pressure during the storage period.
- Unmounted tires are best stored in a vertical position. When storing tires in a vertical position, it is recommended to rotate the tires every 2 weeks to prevent any flat spots from developing. When unmounted tires are stored horizontally, they deform severely and will be difficult to mount on the rim flange.
- Optimal conditions for tire/wheel assembly storage are offered by the Original Porsche Transport Carrier, part number, 000 044 000 22.