Technical Data –
Front Axle, Steering and Rear Axle
|
Front Axle |
|
|
Wheel
suspension |
Independent
suspension, double control arm with coil spring and internal
damper
|
|
Springs |
1 coil
spring per wheel
|
|
Dampers |
Double-action dampers
|
|
Stabilizers |
Ø 28 x 4
mm (tubular stabilizer)
|
|
Steering |
Rack and pinion
power steering with tie rods |
|
Steering
wheelØ |
380 mm
|
|
Steering wheel
ratio (in center position) |
17.75:1
|
|
Turning
circleØ |
11.5 m
|
|
Track
circleØ |
9.6 m
|
|
No. of steering
wheel turns from lock to lock |
3.13
|
|
Rear Axle |
|
|
Wheel
suspension |
Independent wheel
suspension with lower diagonal suspension links and upper
wishbones, coil springs and internal dampers
|
|
Springs |
1 coil spring per
wheel
|
|
Dampers |
Double-action
hydraulic dampers
|
|
Stabilizer |
Ø 22.5 x 3.5 mm
(tubular stabilizer)
|
Wheel Alignment Adjusting
Values*
The following values
apply to curbweight according to DIN 70020 (car with full fuel
tank, spare wheel and tools)
|
|
Adjusting Value and Tolerance |
Max. Difference
Left to Right |
|
Front Axle |
|
|
|
Height setting:
From the contact
surface to measuring point on rear link bearing
|
190 – 20
mm ** |
10 mm |
|
Toe-in
unpressed
|
+ 15’+5’ |
|
|
Track
difference at 20° lock |
-1°+20’ |
may only be
affected by replacing steering arms
|
|
Camber |
+30’+10’ |
10’
|
|
Caster |
3°30’+30’ |
20’
|
|
Rear Axle |
|
|
|
Height setting:
From tire contact
surface to measuring point on cross member |
173 + 10 mm** |
10 mm
|
|
Toe-in per wheel |
+10’+5’ |
10’
|
|
Camber |
-40’+10’ |
10’
|
*The vehicle alignment
settings are applicable to the actual vehicle ride height only
(see repair manual pp. 44-1 etc.)
**The height setting values apply to new vehicles. Used vehicles
may be up to 10 mm lower, i.e. the tolerance may deviate by minus
10mm. This must, however, be the same for both axles.
Technical Data – Braking System
|
Description |
From
Mod. 86
Specifications/
Remarks |
Wear
Limit |
|
New brake disc
thickness
front
rear |
32 mm
24 mm
|
|
|
Brake discs –
Min. thickness** after machining
front
rear |
30.6 mm
22.6 mm |
30.3/30
mm
18.6/22
mm
|
|
Thickness
tolerance for brake disc max. |
0.02 mm
|
|
|
Lateral runout
for brake discs max. |
0.05 mm
|
|
|
Lateral runout
for installed brake discs max. |
1.
mm
|
|
|
Max. surface
finish after machining |
0.006 mm
|
|
|
Play on brake
pedal with brakes bled and engine stopped (footbrake arm
without stop) |
Approx. 10 mm
determined by permanently set clearance at points inside
braking unit
|
|
|
Parking
brake*** (handbrake) |
Drum brake
applied mechanically on both rear wheels
|
|
|
Parking
brake drum dia. |
180 mm |
181 mm
|
|
Brake
shoe width |
25 mm
|
|
|
Brake liner
surface area per wheel |
85 cm2
|
|
|
Brake liner
thickness |
4.5 mm |
1 mm
|
* Fixed calipers with
pistons of dia. 42/36 mm were installed in some cars (USA, Canada,
Australia and Arabian countries) in the 1987 model year.
The front-axle brake calipers with 44/36 mm dia. Pistons can be
retrofitted in 86 models only in pairs.
** Brake disks may only be machined symmetrically, i.e. evenly on
both sides.
*** 87 models onward, parking brake liners made of asbestos-free
material (Energit 559). The liners can be retrofitted to vehicles
earlier than the model year 87 (right-hand and left-hand sides).
Rims, Tires and Tire Pressure
|
Standard tires |
|
Tires |
Rims |
ET** |
|
87 mod. onward
928 S4
928 S4 Club Sport
|
front
rear
front
rear |
225/50 VR 16
245/45 VR 16
225/50 VR 16
245/45 VR 16
(with 17 mm
washer)
|
7 J x 16
H 2
8 J x 16
H 2
8 J x 16
H 2
9 J x 16
H 2 |
65
52.3
60
60 |
|
89 mod
onward
928 GT |
front
rear |
225/50 ZR 16*
245/45 ZR 16*
(with 17 mm
washer)
|
8 J x 16
H 2
9 J x 16
H 2 |
60
60 |
* “ZR” 89
model onward
“VR” above 210 km/h,
“ZR” above 240 km/h
** rim offset in mm
Tire Pressure in bar
(Summer Tires)
|
Type |
928 S4 |
928 S4 Club Sport
928 GT |
|
Front axle |
2.5 bar |
2.5 bar
|
|
Rear axle |
3.0 bar |
3.0 bar |
Collapsible spare tire until 85 models 2.2 bar, 86 models onward
2.5 bar
Winter tires front 2.5 bar, rear 3.0 bar
Checking wheel Rims
Refer to drawing for radial and lateral runout measuring points on
inner and outer rim shoulders.
Max. permissible radial and lateral runout for light alloy rims =
1.0 mm.
Note:
Never straighten distorted wheel rims |
