Summer Tires - Wheel Rim Summary
88porsche08Subject:
Summer Tires - Wheel Rim Summary
Model
924, 924T
944
Group
4
Part Identifier
N/A
Number
8505
March 15, 1985
ATTENTION: This revised page replaces page 1 of bulletin. Group 4, Number 8404, dated December 17, 1984.
Tires tested for Porsche must fulfill a wide range of requirements.
For example:
^ service life
^ high speed strength
^ handling on wet and dry road surfaces
^ adaption to vehicle design
^ comfort
^ rolling noise
^ wear
The following tire and wheel rim sizes are approved for Porsche Types 924, 924 Turbo and 944:
Type 924
165 HR 14 on rim 5-1/2 J x 14 and 185/70 HR 14 on rim 5-1/2 J x 14 or 6 J x 14 205/60 HR 14 on rim 6 J x 15
Type 924 Turbo
185/70 VR 15 on rim 6 J x 15 and 205/60 VR 16 on rim 6 J x 16
Type 944
185/70 VR 15 on rim 7 J x 15 front and rear 215/60 VR 15 on rim 7 J x 15 front and rear or 7 J x 15 front and 8 J x 15 rear
205/55 VR 16 on rim 7 J x 16 front and rear or 205/55 VR 16 on rim 7 J x 16 front and 225/50 VR 16 on rim 8 J x 16 rear
Listed below are tires presently tested and approved by Porsche:
Tires approved by Porsche in past years are listed below. These tires are no longer tested by Porsche and have limited availability in some markets.
Note
Because of the relatively large contact surface of the series 60, 55 and 50 tires, only limited suitability for winter driving can be expected.
Notes on Pirelli P 6 tires
Three different versions of P6 tires have been produced:
A - no special markings
215/60 VR 15
B - cross in circle below size code
C - five pointed stars in circles, 215/60 VR 15 each side of size code
If circumstances make mixed installation necessary the following recommendations should be followed.
Note for Dunlop SP Sport Super Tires
Dunlop SP Sport Super D 1 and D 4 tires must NOT be mixed on one car, either independently or by axle.
The D 1 version is still available, but in limited quantities only. If fitting a complete set of new tires, conversion should be made to the D 4.
General installation instructions
Always use new rubber valves or tubes when replacing tires. Rubber valve Part No. 900.265.001.50
Always coat tire beads with rubber lubricant when mounting tire on rim.
Work sequence
- install new valve stem and remove insert
- install tire on rim and inflate to 4.0 bar (60 psi)
- ensure tire is seated on rim
- install valve stem insert and inflate tire to correct pressure
Tires and tubes
Do not use tubes and tires of different makes.
Tubes are not available for series 50/55 tires.
Tubeless tires should only be mounted with tubes in an emergency situation.
New tire instructions
Always use tires of the same make and type.
When changing tires of only one axle set, new tires should be mounted on wheels of front axle.
If replacing only one tire of an axle set, the difference in tread depth between tires must not exceed 30%.
Matching tires with forged, perforated disc wheel rims
Matching procedure
^ a machined depression on the rim well of the perforated disc wheel rim marks the point of highest radial run-out
^ a red locating dot is pasted on the outside of the rim to mark the same point of highest radial run-out
^ tires are marked with a green dot
- align red and green dots when installing tire on rim
^ dots must be within 30 mm (1 3/16 in.) of each other
Note
If the red locating dot is missing, mark the location of machined depression with chalk or tape before installing tire.
Wheel bolts
a Part No. 803.601,139.B 14 x 1.5 mm, length 25.5 mm, shoulder diameter 24 mm for 5.5 x 14 in. steel rims tightening torque 110 N-m (11 mkp)
b Part No. 477.601.139 14 x 1.5 mm, length 25 mm, shoulder diameter 28 mm for 6J x 14 in. light alloy rims tightening torque 130 N-m (13 mkp)
c Part No. 477.601.139.A 14 x 1.5 mm, length 70 mm, shoulder diameter 28 mm for 6J x 15 in. light alloy rims tightening torque 130 N-m (13 mkp)
Wheel nuts
d Part No. 999.182.003.36 aluminum, for all porsched rims with 5 mounting holes (especially aluminum rims) tightening torque 130 N-m (13 mkp)
e Part No. N.020.121.1 or 900.182.001.01 steel, for all rims with 5 mounting holes (especially steel rims) tightening torque 130 N-m (13 mkp)
Aluminum wheel nuts (d, above)
Aluminum wheel nuts require special care.
Before installing:
- lubricate threads and shoulders of aluminum nuts with Optimoly HT, part No. 999.917.728.00 (Optimoly HT does not affect tightening torque)
- torque nuts to 130 N-m (96 ft.lbs.)
Note
Tighten and loosen aluminum nuts with a socket that grabs entire depth of nut.
CAUTION
Other socket wrenches or wheel wrenches are not approved.
Never use impact tools.
Recommended tire rotation sequence:
Break-in time for new tires
New tires have a vulcanization skin that can cause poor vehicle handling. Handling characteristics improve measurably during the tire break-in period of 600 miles (1000 km).
Vehicle handling characteristics should not be evaluated immediately after tire replacement.
Driving conservatively during the first 600 miles (1000 km) will help to maximize tire life.
After the break-in period, check wheel balance.
Obtain even tire wear by rotating tires after 3000 miles (5000 km).
Tire pressures
Measure tire pressure only when tires are cold. Air pressure increases as tires get hotter and must not be decreased.
Collapsible spare wheel: 2.2 bar (32 psi)
Note
Underinflation can cause tire damage that is not immediately noticeable.
Conditions leading to slow air loss or structural damage
^ damage to bead during installation
^ installation damage from excessive expansion of bead core; tire could part from rim
^ installation damage to inside of tire; could cause loss of air or ply separation
^ punctures from foreign objects (nails, glass, rocks, etc.); moisture can cause rust at puncture
^ squeezing damage (from driving over potholes, curbs, or similar objects)
^ sidewall damage (from rubbing against curb or slipping of road shoulders)
^ cuts in tire (especially sidewalls)
^ damage from underinflation
CAUTION
Porsche recommends replacing a tire if there is damage to the tread or sidewall and any possibility of structural deterioration exists.
Note
Repairing tires with pressurized sealants or tubes is not acceptable.
Retreading tires is not acceptable.
Tread wear indicators:
Wear
Excessive, rapid tire wear is usually attributed to driving habits.
Almost all tires have tread wear indicators specified for the U.S.
The tread wear indicator is a ridge across the tread base at 6 points on the circumference of the tire.
The ridge has a height of 1.6 mm. When tread wear reaches this point, the ridges become visible. The appearance of the wear indicators signals the need for tire replacement.
Damage that impairs true-running of wheels
^ flat spots from standing. Under high temperature conditions, tires may develop flat spots on the contact surfaces during long periods of standing. Driving the car should correct this condition.
^ uneven wear from damaged suspension parts or misalignment. Checking/correcting wheel alignment is necessary along with the replacing of damaged parts.
^ uneven wear from improper balancing. Correct balancing must be performed before damage occurs.
^ flat spots from locked wheels while braking. This damage usually remains noticeable and cannot be repaired.
When checking tire pressures, also check condition of tires. Look for uneven tire wear, damage to tires and rims and damage to suspension parts.
Porsche recommends checking wheel alignment following the first 600 miles (1000 km) of driving or after any repairs to the suspension system.
Storing tires
Rubber ages and is sensitive to certain substances. Ozones, fuels, oils, greases and solvents have a damaging effect.
Storage Information
^ store tires indoors where cool and dry. Temperatures between -10~C and +20~C (14~F and 68~F)
^ clean tires with water before storing
^ store tires in a dark room
^ store tires on rims and inflate to higher pressures
^ do not store tires near heat radiators, electrical equipment, fuels, lubricants, solvents or chemicals
^ do not store tires in direct sunlight or under constant fluorescent lighting. Avoid blue light protection paint on windows.
^ do not store tires by suspending on hooks or in stacks
Note
The assumption that tires are more wear resistant after aging is not valid.
VR rated tires should not be used if older than 6 years.
Age can be determined by the last three digits or the DOT code on the tire sidewall.
For example:
If the last three digits are 193, the tire was manufactured in the 19th week of 1983.
Valve support (applicable to 944 only)
The 7" and 8" Porsche rims must be fitted with valve supports, Part No. 911.361.561 .00 or .01, to avoid lateral stress on rubber valves caused by the design position of the valve bore.