Page 265 of 2490

W
heels and Tires - Wheels and Tires
D
iagnosis and Testing
General Not
es
1.
1. Factory in
stalled tires and wheels are designed to provide optimum ride and ha
ndling characteristics when inflated
to the recommended inflation pressures, with vehicle loads not exceeding the full-rated load capacity.
2. 2. Correct tire pressures and driv ing technique have an important influence on tire life. Heavy cornering, excessively
rapid acceleration and unnecessary sharp braking increase tire wear.
3. 3. Replacement tires should follow the recommended:
Size
.
Speed
rating.
Load range. Radial c
onstruction type.
4. 4. The use of any other size or type of wheel / tire may seriously affect:
Safety. Ri
de.
Handlin
g.
Speed
ometer / odometer calibration.
Vehi
cle ground clearance.
Ti
re clearance between
body and chassis.
Wh
eel bearing life.
Brake cooli
ng.
5. 5. Wheels must be renewed when:
Impact damaged. Heavil
y corroded.
Porous W
heel stud holes or se
ats become damaged.
They h
ave excessive radial or lateral runout.
Safety Notes
• WAR
NINGS:
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
A TIRE AND WHEEL MUST ALWAYS BE CORRECTLY MATCHED. WIDER OR NARROWER TIRES THAN RECOMMENDED
COULD CAUSE DANGER THROUGH SUDDEN DEFLATION.
WHEN USING THE TEMPORARY SPARE WHEEL, SPEED MUST NOT EXCEED 80 KM/H (50 MPH). DRIVE WITH CAUTION
AND REPLACE WITH THE SPECIFIED WHEEL / TIRE ASSEMBLY AS SOON AS POSSIBLE.
TRACTION CONTROL (IF AVAILABLE) MUST NOT BE ENGAGED WITH THE TEMPORARY SPARE WHEEL FITTED.
Page 266 of 2490

WHE
N CHANGING A WHEEL, ENSURE THAT THE VEHICLE CANNOT MOVE. ALWAYS APPLY THE PARK BRAKE AND
SELECT TRANSMISSION 'P' POSITION.
NEVER RUN THE ENGINE WITH ONE WHEEL OFF THE GROUND, FOR EXAMPLE, WHEN CHANGING THE WHEEL. THE
VEHICLE COULD MOVE.
TIGHTEN THE WHEEL NUTS TO SPECIFICATION. WHEELS MAY COME LOOSE IF OVER OR UNDER TIGHTENED.
USE WHEELS AND WHEEL NUTS DESI GNED FOR XJ SERIES VEHICLES ONLY. AFTERMARKET WHEELS OR WHEEL
NUTS MAY NOT FIT OR FUNCTION PROPERLY AND COULD CAUSE INJURY OR DAMAGE.
In
spection and Verification
To maximize ti
re performance, inspec
t the tires frequently for signs of:
Unev
en wear.
Incorrect
ti
re pressure.
Wh
ee
l imbalance.
Cuts. Abrasi
ons.
B
u
lges (blister).
Ply s
e
paration.
Embedded objects. Impact damage.
Inspe c
tion should be
more frequent when:
Continuo
us high speed op
eration is required.
Ra
pid or extreme temperatures changes occur.
R
o
ad surfaces are rough.
Roads ar
e littered
with debris.
Tread W
e
ar Indicator
•
NO
TE: Tire condition must comply with prevailing local legislation.
New tires must be installed if the wear in dicators are exposed or if there is severe shoulder wear. Shoulder wear is usually
caused by either excessive camber or toe on tires.
T i
re Vibration Diagnosis
A
tir
e vibration diagnostic procedure always
begins with a road test. The road test and the custom er interview (if available)
will provide much of the information need ed to find the source of vibration.
During the road test, drive the vehicle on a road that is smooth and free of undulations. If vibration is apparent, note and
record the following:
The s p
eed at which the vibration occurs.
W
h
at type of vibration occurs in each
speed range - mechanical or audible.
How the vibrati
on is affected
by changes in the following:
- -engine torque
- -vehicle speed
- -engine speed.
Type of v i
bration - sensitivity:
- - torque sensitive,
- - vehicle speed sensitive,
- - or engine speed sensitive.
Page 267 of 2490

The
following explanations will help isolate the source of vibration.
Torque Sensitive
This
means that the condition can be impr
oved or made worse by accelerating, dece lerating, coasting, maintaining a steady
vehicle speed, or applying engine torque.
Ve
hicle Speed Sensitive
This means th
at the vibration al
ways occurs at the same vehicle speed and is not affected by engine torque, engine speed
or gear selection.
Engine Speed Sensit
ive
This means th
at the vibration
occurs at varying vehicle spee ds when a different gear is selected. It can sometimes be
isolated by increasing or decreasing engine speed with the tran smission in neutral or by stall testing with the transmission in
gear. If the condition is engine speed sensitive, the cause is probably not related to tires.
If the road test indicates that there is tire wine, but no shake or vibration, the noise originates with the contact between th e
tire and the road surface.
A thumping noise usually means that the tire is flat or has soft spots making a noise as they slap the roadway. Tire whine
can be distinguished from axle no ise, as tire whine remains the same over a range of speeds.
Sym
ptom Chart
Sy
mptom Chart
Sy
mptom
Possib
le Sources
Acti
on
Uneven ti
re wear.
Incorrect ti
re inflation.
*
Cor
rect to specification.
*
Exce
ssive radial an
d lateral runout.
*
Renew tire
or wheel.
*
O
ut of specification steering
geometry.
*
R
ealign steering geometry: Refer to Section 204-
00.
*
W
orn ball joint.
*
Renew
damaged component, realign steering
geometry.
*
W
orn tie-rod end.
*
R
enew component, realign steering geometry.
*
Incorrect
tire / wheel usage.
*
Inst
all correct tire and wheel combination.
*
Loose or leaki
ng shock absorbers.
*
Tigh
ten or Renew as nece
ssary: Refer to Section
204-00.
*
Suspensi
on geometry out of
alignment.
*
Che
ck and adjust: Refer to Section 204-00.
*
Loose, worn or da mage
d suspension
components.
*
In
spect, Repair or Renew as necessary.
*
Wh
eel and tire assembly out of
balance.
*
Balance wheel an
d tire assembly.
*
Excessive later
al or radial runout of
wheel or tire.
*
Check, Repair o
r
Renew as required.
*
Tire
s show excess wear on
edge of treads.
Ti
res under-inflated.
*
Cor
rect pressure to specification.
*
Vehi
cle overloaded.
*
Cor
rect to specification.
*
Tire
s show excess wear on
edge of treads (with tire
pressures correct).
Incorre
ct toe setting.
*
Se
t to specification: Refer to Section 204-00.
*
Tire
s show excess wear in
center of tread.
Tire
s over-inflated.
*
Cor
rect pressure to specification
*
W
heel mounting is
difficult.
Incorrect app
lication or mismatched
parts, including wheel studs and
wheel nuts. Corroded, worn or
damaged parts.
*
Fol
low the manufacturer's specifications. Clean or
Renew.
*
Wobble or sh
immy
affecting wheel runout.
Damaged wh
eel (eventually
damaging wheel bearings and causing
uneven tire wear).
*
Inspect wheel rims for
damage and runout. Renew
as required.
*
Vehicle vibrations from
Tire
s / wheels mismatched.
*
Inst
all correct tire / wheel combination.
*
Page 268 of 2490

wheels
and tires.
Infl
atio
n pressure too high or low.
*
Cor r
ect pressure to specification
*
Uneven ti re wear.
*Re fe
r to Diagnosis and Testing in this section.
*
Wh ee
l and tire assembly imbalance.
*
Balance wheel an d tire assembly.
*
Brake disc imbalan c
e.
*
Check brak e disc co
oling fins for mud and foreign
material. Check for damage or disc heavy spot.
Refer to Section 206-00.
*
Damaged or distor
ted wh
eel.
*
Renew wh eel.
*
Excessive radial run-o
ut of wheel or
tire. Excessive lateral run-out of wheel or
tire.
*
*
Renew wh
eel or tire.
*
Incorrectl y
seated tire.
*
R e
mount the tire.
*
Loose wh eel mo
untings: damaged
wheel studs, whee l nuts, worn or
broken wheel hub face or foreign
material on mounting faces.
*
Tigh
te
n or Renew worn or
damaged parts. Clean
mounting surfaces.
*
De
fe
ctive wheel bearings.
*
Renew worn
or damaged bearing sets: Refer to
Section 204-00.
*
W
a
ter in tires.
*
R e
move water.
*
Damaged wh eel stud
thre
ads.
Sli
d
ing wheel across the wheel studs
during installation. Loose wheel nuts.
*
Renew wh
eel studs.
*
Broken wh eel
studs.
Loose or overti
ght
ened wheel nuts.
*
Renew wh eel studs.
*
C o
rrosion / contamination
streaks from wheel stud
holes.
Loose wh eel
nuts.
*
Chec k com
plete assembly. Renew damaged parts.
Apply correct torque setting.
*
Damaged wh
eel nu
ts.
Loose wh
eel
assembly.
Over-tightened wheel nuts.
*
*
Renew wh
eel nu
ts. Apply correct torque setting.
*
Se ize
d wheel nuts.
Cor
rosion
*
CAUTI O
N: Do not permit lubricant to
contaminate wheel hub stud holes or wheel nut seats.
If corrosion is light, wire brush away corrosion. If
corrosion is excessive renew wheel studs and wheel
nuts. Lubricate th e first three threads of wheel
studs with a graphite based lubricant.
*
Page 269 of 2490
W
heels and Tires - Wheel and Tire
Re
moval and Installation
Remov
al
CAUTI
ON: Do not use heat to loosen a seized wheel nut: heat will change the metal's properties and damage wheel
bearing and brake caliper seals.
I
nstallation
1.
NOTE
: Certain Jaguar wheels are fitted wi
th a hexagon wheel
nut cover
R
emove the cover with the plastic spanner supplied with
the spare wheel jacking equipment.
2. Loosen
, but do not
remove wheel nuts.
3. Raise vehicle and support on st ands. Refer to Section 100-02.
4. R
emove wheel and tire assembly.
1. Remove wheel nuts.
2. Remove wheel.
1. CAUTION: Do not allow grease to contaminate the wheel
stud threads and wheel nut to wh eel mating surface, as this may
cause the nuts to loosen.
• NOTE: To prevent the wheel corroding on to the hub, smear a
thin layer of grease onto the hub mounting face and spigot; and
wheel mounting face and spigot hole.
Page 270 of 2490
Instal
l the wheel an
d tire assembly.
1. Install wheel.
2. Install wheel nuts to secure wheel in position.
3. Lower vehicle.
4. Tighten wheel nuts in a diagonal sequence to:
Steel wh
eel 68-82 Nm.
Al
loy
wheel 88-102 Nm.
Page 271 of 2490
Vehicle Dynamic Suspension - Vehicle Dynamic Suspension
Description an
d Operation
Front Sho
ck Absorbers
The front shock absorber
comprises:
A
coil-type road spring, mounted between the lower wish
bone spring pan and the front suspension crossbeam;
different spring rates are used according to model.
A
telescopic, hydraulically controlled, damper mounte
d between the lower wishbone and the vehicle body.
It
em
De
scription
1Front
suspension crossbeam
2Front
hub assembly
3Ro
ad spring
4Dam
per
Page 272 of 2490
The rear shock ab
sorber comprises:
A
c
oil-type road spring mounted between the lower wish
bone and the upper spring seat on the vehicle body;
different spring rates are used according to model.
A te
lescopic, hydraulically controlled, damper, co-axial wi
th the road spring, mounted between the lower wishbone
and the upper spring seat on the vehicle body.
Damp
ing Principle
D
a
mping is achieved by controlling the flow of fluid from one
end of the damping chamber to the other. The more the flow
of fluid is restricted, the firmer the damping action.
Ite
m
De
scr
iption
1Dam
p
er
2Ro
ad s
pring
3Lower wishbon
e
4Upper sprin
g seat
Rear Shock A
b
sorbers