brake AUDI A8 2012 Workshop Manual

scalding from hot coo lant by following
these steps.
- Turn
off the engi ne and a llow it to cool
down.
- Protect your face, hands and arms from
escapi ng fl uid and steam by cover ing
the cap with a large, thick rag .
- Turn the cap slowly and very ca refully
i n a cou nte r-clockw ise dir ect ion while
a pply ing lig ht, downwa rd p ress ure on
the top of the cap.
- T o avo id being burned, do no t sp ill an­
tifree ze o r coolan t on t he exh aust sys­
tem or ho t engine parts . Un der certain
conditions, the ethylene glyco l in en­
gine coolant can catch fire .
- Antifree ze is poisono us. Always store an­
tifreeze in its or iginal co ntainer and we ll
o ut o f the reac h of children.
- If you drain the coolant , it must be
caught and safely stored in a p roper con ­
tainer clear ly marked "poison".
(D Note
- Coolant po llutes the env ironment and
could ca use a n engine fire . Excess coo l­
ant wi ll be forced out through the pres ­
sure re lief va lve in the cap when the en­
gine becomes hot.
- If, in an emergency, only water can be
added , the correct ratio between water
and antifreeze¢
page 22 7 must be re­
stored as soon as possib le .
@ For the sake of the environment
Drained coolant should not be re used . Al­
ways dispose of used c oolant while observ­
ing all envir onmental regulations .
Radiator fan
The radiator fan switches on automa tically by
itself
T he radiator fan is driven by the engine via the
V-be lt. The viscous clutch regulates the speed
of the fan according to the temperature of the
coolant .
Checkin g and fillin g 229
An auxiliary electric radiato r fan* sw itches on
and
off depending on coolant temperature
and othe r vehicle ope rat ing con ditions.
After yo u switc h the engi ne off, the aux iliary
f an can con tinue r unning for up to 10 minutes
- even with the ignition off. It can even switch
on again later by itself¢ & , if
- t he temperatu re of the engine coo lant rises
due to the heat b uild -up from the en gine in
the engi ne compartment, or
- the engine compartment heats up be cause
the vehicle is parked in intense sunlight.
A WARNING
- To reduce the risk of personal in jury nev­
er touch the radiator fan.
- The a uxiliary electric fan is temperat ure
contro lled and can switch on sud denly
even when the engine is not running.
- The a uxiliary radiator fa n switches on a u­
tomatically when the engine coo lant
reaches a certain temperature and will
continue to run until the coo lant temper­
ature drops .
Brake fluid
Checking brake fluid level
The brake fluid level can be checked with a
qui ck glance.
Fig. 180 En gin e compar tment: cov er o n th e bra ke fluid
r ese rvoir
Befo re you check anyth ing in the eng ine com­
partment ,
always re ad and heed all WARN­
INGS c::> ,& in Working in the engine compar t-
ment on page 219 . .,..

230 Check ing and filling
• Read the brake fluid level from the brake
fluid reservoi r¢
fig. 180, ¢ page 221. The
brake f lu id leve l must be between the "MIN"
and "MAX" markings.
The location of the brake fluid reservoir can be
seen in the engine compartment illustration
co page 221.
The fl uid level may drop slightly after some
time due to the automatic adjustment of the brake pads . This is not cause for alarm .
I f the brake fluid level falls
considerably be­
l ow the "MIN" mark, the brake wa rning/indi ­
cator light- (U.S.
models) ;II (Canadian
models) will come on ¢
page 14. Do not con­
tinue to operate the vehicle. The comp lete
brake system should be thoroughly checked
by an authorized Audi dealer or other quali­
fied fac ility and the cause corrected. If the
brake fluid level is too low, the brake war ning/
in dicato r light w ill illuminate . Contact an au­
thor ized A udi dealer
immediately .
Changing brake fluid
Have the brake fluid changed by an experi­
enced technician .
Brake fluid absorbs moistu re from the a ir . If
the water content in the brake fluid is too
h igh, corrosion in the brake system may result
after a per iod of t ime . The bo iling po int of the
b rake fluid w ill also decrease considerably and
dec rease braking per formance.
Therefore, the brake flu id must be changed
e ver y two yea rs. A lways use new b rake fluid
which confo rms to Fede ral Motor Vehicle
Standard "FMVSS 1 16 DO T 4".
The brake flu id rese rvoi r ca n be difficult to
r ea ch, therefo re , we re commend that yo u
have the brake fl uid changed by yo ur a utho r­
ized
Audi dealer. Your dea ler has the correct
too ls, the right brake fluid and the know-how
to do this for you .
A WARNING
-Brake flu id is poisonous. It must be stor­
ed only in the closed or iginal conta iner
out of the reach of children!
- Brake failure can resu lt from o ld or inap­
prop riate brake flu id . Obse rve these pre ­
cautions:
- Use only brake fluid that meets SA E
specification
J 1703 and conforms to
Federa l Moto r Ve hicle Standard 1 16 .
A lways check with your authorized A udi
dealer to make sure you are using the
correct brake fluid . The cor rect type of
brake flu id is also ind icated on the
brake flu id rese rvoir .
- The brake fluid must be new . Heavy use
of the brakes can cause a vapo r lock if
the b ra ke fluid is left i n the system too
l o ng. This can se riously affect the effi ­
c iency of the br akes as well as your
sa fety. This co uld resu lt in an accident.
(D Note
Brake fluid will damage the pai nt of you r
vehicle.
@ For the sake of the environment
Because of the p rob lem of proper disposal
of b ra ke fluid as well as the spec ial too ls
r equired and the nece ssary expe rti se, we
r ecommend that yo u have the brake fl uid
changed by yo ur authorized Aud i dea ler.
Battery
General information
U nder normal operat ing cond itions, the bat­
te ry in yo ur Audi does not need any ma inte­
nance . With
high outside temperatures or
l o ng da ily d rives we recommend that you have
the e lec trolyte leve l checked by a serv ice fa­
c ility. The electrolyte leve l should also be
checked each time the battery is cha rged
¢ page 233. .,..

Tires and wheels
Tires
General notes
Tires may be the least appreciated and most
abused parts of a motor vehicle .
Tires may be the least appreciated and most
abused parts of a motor vehicle . T ires are,
however, one of the most important parts of a
vehicle, particularly considering the compara­
tively small patch of rubber on eac h tire that
assures that a ll- important contact between
you, you r vehicle and the road.
Maintaining the correct tire pressure, mak ing
sure that your vehicle and its tires do not have
to carry mo re weight than they can safely han­
d le, avoiding damage from road hazards and
r eg ularly inspec ting t ires for damage i nclud­
ing cuts, slashes irregu la r wear and ove rall
condition are the most important things that
you can do to he lp avoid sudden tire failure in­
cluding tread separat ion and blowouts.
Avoiding damage If you have to d rive over a curb or similar ob­
stacle, drive very slow ly and as close as possi ­
b le at a right angle to the curb.
A lways keep chemicals includ ing grease, o il ,
gasoline and brake fluid off the t ires .
I nspect the t ires regularly for damage (cuts,
cracks or b listers, etc.). Remove any fo reign
bod ies embedde d in the treads.
Storing tires Mark tires when you remove them to indicate
the direction of rotation . T his ensures you to
be ab le to mount them correctly when you re­
i nstall them .
When removed, the whee ls or t ires should be
sto red in a cool, d ry and preferably dark place .
Store tires in a vertical pos ition if they are not
mounted on rims, in a horizontal pos it ion if
they are mounted on rims .
Tires an d wheel s 235
New tires
New tir es have to be broken in ¢ & .
The tread depth of new t ires may vary, accord­
ing to the type a nd make of t ire and the tread
pa tte rn.
Hidden damage
Damage to tires and r ims is ofte n not readily
visible . If you notice unusual v ib rat io n or the
vehicle p ulls to one s ide, th is may ind icate
that one of the t ires has been damaged . T he
ti res m ust be chec ked immed iate ly by an au­
thorized Audi dea le r or q ua lified wor kshop .
Unidirectional tires
A un idirectional tire can be identified by ar­
rows on the s idewa ll, that po int in the direc­
tion the t ire is designed to rotate. You mus t
f ol low the specified di rection o f rotation . T his
is necessary so that these tires can develop
their optimum characteristics regarding grip, road noise, wear and hydrop laning resistance.
For more information ¢
page 264.
A WARNING
New tires or t ires that are o ld, worn or
damaged cannot provide maximum con­
trol and braking ability .
-
-New tires tend to be slippery and must
be broken in. To reduce the r isk of losing
control, a co llision and ser ious personal
in ju ries, d rive with special ca re fo r the
fi rst 350 m iles ( 560 km).
- Driving with worn or damaged tires can
lead to loss of control, sudden tire fail­
ure, including a blowout and sudden de­
fl ation, c ras hes and se riou s personal in­
juries . Have wo rn or damaged t ires re­
placed immediate ly.
- Ti res age even if they are not being used
and can fai l sudden ly, especially at hig h
spee ds. Tires that are more than 6 years
old can only be used in an emergency
and then w ith special care and at low
speed.
•
•

236 Tires and wheels
-Never mount used tires on yo ur vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
Glossary of tire and loading terminology
Accessory weight
means the comb ined weight (in excess of
those standard items which may be rep laced)
of automatic transmission, power steering, power brakes, power windows, power seats,
radio, and heater, to the extent that these
items are availab le as factory -installed equip ­
ment (whether installed or not) .
Aspect ratio
means the ratio of the he ight to the w idth of
the tire in percent. Numbers of 55 or lower in­
dicate a low sidewall for improved steering re­
sponse and better overall handling on dry
pavement.
Bead
means the part of the tire that is made of
steel wires, wrapped o r reinforced by ply cords
and that is shaped to fit the r im.
Bead separation
means a breakdown of the bond between
components in the bead.
Cord
means the strands forming the plies in the
tire.
Cold tire inflation pressure
means the tire pressure recommended by the
vehicle manufacturer for a tire of a designated size that has not been driven for more than a
couple of miles (kilometers) at low speeds in
the three hour period before the tire pressure
is measured or adjusted. -
If you notice unusual vibration or if the
veh icle pulls to one side when driv ing, a l­
ways stop as soon as it is safe to do so and check the wheels and tires for dam­
age.
Curb weight
means the weight of a motor vehicle w ith
standard equipment including the maximum
capacity of fuel, oil, and coolant, air condi­
tioning and additional weight of optiona l
equipment.
Extra load tire
means a t ire design to operate at h igher loads
and at higher inflation pressures than the cor­
responding standard tire. Extra load tires may
be identified as "XL", "xl", "EXTRA LOAD", or
"R F" on the sidewall .
Gross Axle Weight Rating ( "GAWR ")
means the load-carrying capacity of a s ingle
axle system, measured at the tire-ground in­
terfaces .
Gross Vehicle Weight Rating ("GVWR")
means the maximum total loaded weight of
the vehicle.
Groove
means the space between two adjacent tread
ribs .
Load rating (code)
means the maximum load that a tire is rated
to carry for a given inflation pressure. Yo u
may not find this information on all tires be­
cause it is not required by law.
Maximum load rating
means the load rating for a tire at the maxi­
mum permissib le inflation pressure for that
tire.

Maximum loaded vehicle weight
means the sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight, and
(d) Production options weight
Maximum (permissible) inflation pressure
means the maximum cold inflation pressure
to which a tire may be inflated. Also called
"maximum inflation pressu re."
Normal occupant weight
means 150 lbs. (68 k ilograms) times the
number of occupants seated in the vehicle up
to the total seating capacity of your vehicle.
Occupant distribution
means distribution of occupants in a vehicle .
Outer diameter means the overall diameter of an inflated new
tire.
Overall width
means the linear distance between the exteri­
ors of the sidewalls of an inflated tire, includ­
ing e levations due to labeling, decorations, or
protective bands or ribs.
Ply
means a layer of rubber-coated para llel cords.
Production options weight
means the comb ined weight of those installed
regular production options weighing over 5
lbs . (2 .3 kg) in excess of those standard items
which they replace, not previously considered
in curb weight or accessory weight, including
heavy duty brakes, r ide leve lers, roof rack,
heavy duty battery, and specia l trim .
Radial ply tire
means a pneumatic t ire in which the p ly cords
that extend to the beads are laid at substan­
tially 90 degrees to the centerline of the
tread.
Tires and wheels 237
Recommended inflation pressure
see~
page 236, Cold tire inflation pressure.
Reinforced tire
means a t ire design to operate at higher loads
and at higher inflation pressures than the cor­
responding standard tire. Reinforced tires
may be identified as "XL ", "x l", "E XTRA LOAD",
o r "R F" on the sidewall.
Rim
means a metal support for a tire or a t ire and
tube assembly upon which the tire beads are
seated.
Rim diameter
means nom inal d iameter of the bead seat. If
you change your wheel s ize, you w ill have to
purchase new tires to match the new r im di­
ameter.
Rim size designation
means r im diameter and width.
Rim width
means nom inal distance between rim fla nges.
Sidewall
means that portion of a tire between the
tread and bead.
Speed rating (letter code)
means the speed at which a tire is designed to
be driven for extended periods of time. The
ratings range from 93 mph (150 km/h) to
186 mph (298 km/h)
~ page 247 . You may
not find this information on all tires because
it is not requ ired by law.
The speed rating letter code, where applica­
ble, is molded on the tire sidewall and indi­
cates the max imum pe rm issib le road speeds
~ .&. in Winter tires on page 251.
Tire pressure monitoring system*
means a system that detects when one or
more of a veh icle's tires are underinflated and
illuminates a low tire pressure warning tell­
tale.
•
•

vehicle from handling properly and in­crease the risk of a loss of veh icle con­
tro l.
- The brakes on a veh icle that has been
overloaded may not be able to stop the
vehicle within a safe distance.
- Tires on a vehicle that has been overload­ ed can fail suddenly causing loss of con­
tro l and a crash .
- Always make sure that the tota l load be­
ing transported -including the we ight of
a tra ile r hitch and the tongue weight of a
loaded trailer -does not make the veh i­
cle heav ier than the veh icle's Gross Vehi­
cle Weight Rating.
A WARNING
- Incorrect tire pressures and/or underin­
flation can lead to a serious o r fatal acci­
dent.
- Incorrect tire pressures and/or underin­
flation cause increased tire wear and can
affect the handling of the vehicle .
- Incorrect tire pressures and/or underin­
flation can also lead to sudden tire fa il­
ure, including a blowo ut and sudden de­
flation, causing loss of vehicle control.
Checking tire pressure
.
The correct tire pressure for the tires original­
ly installed on your vehicle is listed on the tire
pressure Lobel located on driver's side 8-pil­
lor.
The recommended tire pressures are on the
tire pressure labe l and in the tab le
c:> page 239, Cold tire inflation pressure .Th is
means that the pressure must be checked and
adjusted when the tire has not been driven for
more than a couple of m iles (kilometers) at
low speeds during the previous three hours.
Air in the tires expands when the tire heats up
as a result of inte rna l fr iction as it flexes in
use. The ti re p ress ure is higher when the tire
h as warmed up than when it is "cold."
It is the inflat ion pressure in a "cold " tire that
counts. Therefo re, you shou ld neve r let air out
Tire s an d wheel s 241
of a wa rm tire to match "Cold tire inflat ion
pressure" recommendations
c:> page 239. T he
tires wou ld then be underinflated and cou ld
fail suddenly .
T he t ire pressure label on your Audi lists the
recommended co ld tire inflation pressures at
maximum capacity for the new, orig inal
equipment tires that were on your vehicle at
the time it was manufactured. For the loca­
tion of the labe l
c:>poge 239, fig . 183 .
Most tires lose air natura lly over t ime. They
can a lso lose some air if you drive over a pot­
hole or hit a curb while park ing. It is usually
not possible to see whether the rad ia l tires
used today are underinflated just by looking
at them.
Therefore, be sure to check t ire pressures at
least once a mo nth and a lways before going
o n a long tr ip . Make sure to take the number
of peop le and the amount of luggag e into ac­
count when adjust ing tire p ressu re for a trip -
even one th at yo u wo uld not conside r to be
"long." See¢
page 243, Tires and vehicle
load limits
for mo re important information .
Always use an accura te ti re pressu re gauge
whe n checking and adj usting i nflation pres­
s ur es . Check a ll of the tires and be sure not to
forget the spare tire.
If the pressure in any tire
is too high when the ti re is "cold," let air o ut
of the t ire s low ly w ith the edge of the tire
gauge and keep checking the pressure until
you reach the pressure that is correct for the load (passengers and luggage) and k ind of
driv ing you plan to do .
If the pressure in any tire is too low, note the
difference be tween the pressure in the cold
ti re and the pressure you need and add the air
that you need to reach the correct pressure for
the ve hicle load (passengers and luggage) for
t h e tires on you r veh icle as l isted on the on
you r vehicle and in this ma nual a nd the k ind
of driving you plan to do.
Nev er e xceed the ma ximum inflation pre s­
s ure lis te d on the tir e sidewall for any re a­
son.
•
•

@ For the sake of the environment
Underinflated tires will a lso increase the
fue l consumption .
Tires and vehicle load limits
There are limits to the amount of load or
weight that any vehicle and any t ire can carry.
A vehicle that is overloaded w ill not handle
well and is more difficult to stop. Overload ing
can not only lead to loss of vehicle control, but can a lso damage importan t pa rts of the
ve hicle and can lead to s udden tire failure, in­
cluding a blowout and sudden deflation that
can cause the veh icle to crash.
Your safety and that of yo ur passenge rs a lso
depends on making s ure that load limits are
not exceeded. Vehicle load includes everybody
and everything in and on the vehicle. These
load limits are technica lly referred to as the
vehicle's
Gros s Vehicle We ight R ating
("GVWR").
The "GVWR" includes the weight of the basic
vehicle, all factory insta lled accessories, a full
tank of fue l, oil, coolant and other fluids plus
maximum load. The maximum load includes
the number of passengers that the vehicle is intended to carry ("seating capacity") with an
assumed weight of 150 lbs (68 kg) for each
passenger at a des ignated seat ing pos ition
and the total we ight of any l uggage in the ve­
hi cle. If you tow a trailer, the weight of the
trailer hitch and the tongue weight of the loaded trailer must be included as part of the
vehicle load.
The
Gro ss Axl e W eight R ating ("GAWR") is
the maximum load that can be app lied at each
of the vehicle's two axles.
The Gross Vehicle Weight Rating and the
Gross Axle Weight Rating a re listed on the
safety compliance sticker labe l located on the
driver's side B -pillar . Your Audi has 5 seating
positions, 2 in the front and 3 in the rear for
total seating capacity of 5. Vehicles with pow­
er individual rear seats* have 4 seating posi­
tions, 2 in the front and 2 in the rear for total
Tire s an d wheel s 243
seating capacity o f 4 . Each seating position
has a safety belt~ page 134, Safety belts .
T he fact th at there is a n upper limit to yo ur
vehicle's G ross Vehicle Weight Rating means
that the total weight of whatever is being car­
ried in the vehicle (including the weight of a
tra iler hitch and the tongue weight of the
l oaded tra iler) is lim ited. The more passen­
gers in the vehicle or passengers who are
heavier than the standard we ights assumed
mea n that less we ight can be carried as lug­
gage .
The tire pressure label on your Audi also lists
the maximum combined weight of all of the
occupants and luggage or other cargo that
the vehicle can carry . For the locat ion of the
label ~page239, fig.183.
A WARNING
Overloading a vehicle can cause loss of ve­
hicle contro l, a crash or other accident, se­
rious personal injury, and even death.
- Ca rrying more we igh t than your veh icle
was des igned to carry wi ll prevent the
vehicle from handling properly and in ­
crease the risk of the loss of vehicle con­
trol.
- The brakes on a vehicle that has been
overloaded may not be able to stop the
veh icle w ith in a safe distance.
- Tires on a vehicle that has been over load­
ed can fail suddenly, incl uding a blowout
and sudden deflation, causing loss of
control and a crash .
- Always make sure that the total load be­
ing transported -includ ing the weight of
a trailer hitch and the tongue we ight of a
loaded trailer -does not make t he vehi­
cle heavier than the vehicle's Gross Vehi­
cle Weight Rating.
Determining correct load limit
U se the exa mple be lo w t o cal­
c ulat e th e t otal weight of the
pa sse ngers a nd lu gg age or
•
•

246 Tires and wheels
& WARNING
Sudden tire failure can lead to loss of con­
trol, a crash and serious personal injury!
- Never drive a vehicle when the tread on
any tire is worn down to the wear indica­
tors.
- Worn tires are a safety hazard, they do
not grip well on wet roads and increase
your risk of "hydroplaning" and loss of control.
- Always keep chemicals that can cause tire damage, such as grease, oil, gasoline
and brake fluid away from tires.
- Tires age even if they are not be ing used
and can fail suddenly, especially at high
speeds. Tires that are more than 6 years
old can only be used in an emergency
and then with special care and at lower
speeds.
- Never mount used tires on your vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
New tires and replacing tires and wheels
New tires and wheels have to be broken in .
Fig. 187 Tir e specificat ion codes on the s idewall of a
t ire
No. Description
(!) Passenger car tire (where applicable)
@ Nominal width of t ire in millimeters
@ Ratio of height to width (aspect ratio)
© Rad ial
® Rim diameter code
@ L oad index and speed rating
(J) U.S. DOT tire identification number
@ Audi Original tire
@ Sever snow conditions
@ T ire ply composition and materials
used
Maximum load rating
Treadwear, traction and temperature
grades
Maximum permissible inflation pres­
sure
T he tires and rims are essential parts of the
vehicle 's design . The tires and rims approved
by Audi are spec ially matched to the charac­
teristics of the vehicle and can make a major .,..

Driving with different tires reduces vehi­
cle handling and can lead to a loss of
control.
- If the spare tire is not the same as the
tires that are mounted on the vehicle -
for example with winter tires -only use
the spare tire for a short period of time
and drive with extra care. Refit the nor­
mal road wheel as soon as safely possi­
ble.
- Never drive faster than the maximum
speed for which the tires on your vehicle
are rated because tires that are driven
faster than their rated speed can fail
suddenly.
- Overloading tires cause heat build-up,
sudden tire failure, including a blowout
and sudden deflation and loss of control.
- Temperature grades apply to tires that
are properly inflated and not over or un­
deri nflated.
- For technical reasons it is not always
possible to use wheels from other vehi­
des -in some cases not even wheels
from the same vehicle model.
- If you install wheel trim discs on the ve­
hicle wheels, make sure that the air flow
to the brakes is not blocked. Reduced air­
flow to the brakes can them to overheat, increasing stopping distances and caus­
ing a collision.
- Run flat tires may only be used on vehi­
cles that were equipped with them at the
factory. The vehicle must have a chassis designed for run flat tires . Incorrect use
of run flat tires can lead to vehicle dam­
age or accidents. Check with an author­
ized Audi dealer or tire specialist to see if
your vehicle can be equipped with run flat tires. If run flat tires are used, they
must be installed on all four wheels. Mix­
ing tire types is not permitted.
- For technical reasons, it is not generally
possible to use the wheel rims from oth­
er vehicles. This can hold true for wheels
of the same vehicle type.
Tires and wheels 249
- If the spare tire is different from the
tires that you have mounted on your ve­
hicle (for example winter tires or wide
profile tires), then use the spare tire for a
short period of time only and drive with
extra care. Replace the flat tire with the
tire matching the others on your vehicle
as soon as possible .
- Never drive without the valve stem cap .
The valves could get damaged.
@) For the sake of the environment
Dispose of old tires in accordance with the
local requirements.
' Uniform tire quality grading
-Tread wear
- Traction AA A B C
- Temperature ABC
Quality grades can be found where applicable
on the tire side wall between tread shoulder
and maximum section width
c:> page 246,
fig. 187.
For example: Tread wear 200, Traction AA,
Temperature A.
All passenger car tires must conform to Feder­
al Safety Requirements in addition to these
grades.
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course.
For example, a tire graded 1S0 would wear
one and one half (11/2) times as well on the
government course as a tire graded 100.
The relative performance of tires depends
upon the actual conditions of their use, how­
ever, and may depart significantly from the
norm due to variations in driving habits, serv­
ice practices and differences in road character-
istics and climate. .,.. •
•

252 Tire s and wheel s
chains because the vehicle will be ex­
tremely low. If you do drive with snow
chains on while the vehicle is at this lev­
el, the snow chains might severe ly dam­
age the wheelhouse and other parts of
the veh icle.
(D} Tips
Where snow chains are mandatory oncer­
tain roads, this normally also applies to ve­hicles with All Wheel Drive.
Wheel bolts
Wheel bolts must always be tightened to the
correct torque .
The design of whee l bolts is matched to the
factory installed r ims. If different rims
are fit­
ted, the correct wheel bolts with the right length and correctly shaped bolt heads must
be used. This ensures that wheels are fitted
secure ly and that the brake system functions
correctly .
In certain circumstances, you may not use
wheel bolts from a different vehicle -even if it
is the same mode l
¢page 282.
_& WARNING
Imprope rly tig htened o r maintained whee l
bolts can be come loose ca using loss of
contro l, a co llision and serious persona l in­
jury.
- Always keep the wheel bol ts an d the
threads in the wheel hubs clea n so the
wheel bolts can tu rn easily and be prop­
er ly tightened .
- Never grease or oil the wheel bo lts and
the threads in the wheel h ubs. They can
become loose w hile driving if greased or
oiled, even if tightened to the specif ied
torque.
- Only use wheel bolts that belong to the rim being installed.
- Never use different whee ls bolts on your
vehicle.
- Always maintain the correct tighten ing
torq ue for the wheel bo lts to reduce the risk of a whee
l loss. If the tightening tor­
que of the wheel bolts is too low, they
can loosen and come out when the vehi­
cle is mov ing. If the tighte ning torque is
too high, the wheel bolts a nd threads
can be damaged and the whee l can be­
come loose.
([) Note
The specified torque for the whee l bolts is
90 ft lb (120 Nm) with a tolerance of± 7,4
ft lb(± 10 Nm). Torque whee l bolts diago­
nally. Afte r changing a whee l, the torque
must be checked as soon as possible wi th a
torque wrench -pre ferably by an au thor­
ized Audi dealer or qualified workshop .
Low aspect ratio tires
Your Audi is factory-equipped with low aspect
ratio tires. These tires have been thoro ughly
tested and been se lected specifically for your
model for their superb performance, road fee l
and hand ling u nder a var iety of d riv ing condi ­
t ions . As k your author ized Audi dealer for
more details.
The low aspect ratio of these tires is ind icated
by a numeral of
55 or less in the tire's s ize
designation . The numeral rep resents the ratio
of the t ire's s idewa ll height in relation to its
t read width ex pressed in percentage. Conven­
tiona l tires have a he igh t/w idth rat io of 60 or
more.
The performanc e of low -a sp ec t-ratio tires i s
pa rticularly sensitive to improper inflation
pre ssure . It is therefore important that low
a spect ratio tires are inflated to the specified
pre ssure and that the inflation pressure i s
regularly checked and maintained. Tire pre s­
sures should be checked at least once a month and always befo re a long trip
¢ page 241, Checking tire pressure .
What you can do to avoid tire and rim
damage
Low aspect ratio tires can be damaged more
easily by impact w ith potholes, curbs, gull ies .,..