2008 AUDI S8 tire pressure

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_ t_t_e _ c_ h_ n_o _l_o _....g ,_,y'-_IJIII
T he direction in which the driver wishes to travel is determined with
t he aid of the steering angle and vehicle speed and is con tinua lly
compared with the actual behavior of the vehicle. If the two do not
match, for example, when the vehic le starts hydrop laning on a wet
road, ESP will automatically brake the appropriate whee l to correct
the prob lem.
The vehicle is then stabi lized by the forces act ing on the whee l
during braking. If the vehicle is
oversteering (rear tends to skid out
of the turn), the brakes are mainly app lied on the whee l that is on
the outside of the curve. In the case of a vehicle that is
understeering
(tendency to s lide out of the curve), t he brakes are applied a t the
rear wheel that is on the inside of the curve. An acoustic signal indi ­
cates when ESP brake app lication cuts in
=> & .
The system operates across t he entire speed range in comb inat ion
with the ABS system
=> page 272 . If the Anti -Lock Brake System
(ABS) malfunctions, the ESP wi ll be out of act ion as well.
Ac tivation
When you turn on the eng ine, ESP will automatically be activated
and wil l perform a self -test.
The system can be activated or deactivated by pressing the but ton
=> page 268, fig. 254 . The warning light comes on when the system
is switched off
=> page 18.
Normally, the ESP s hould always be on, however, it may be advanta­
geous to turn off the system in certain special cases when some
degree of wheel spin is des ired such as:
• when driving with snow chains
• whe n driving in deep snow or on a loose surface (to allow the
whee ls to dig in to reach firm ground)
• whe n trying to
"rock" the vehicle free whe n it has become stuck.
T he system should be reactivated once you are no longer in such
situations .
Both the ABS and EDS systems are still functioning even if the ESP
is switched off .
Controls and equip­
ment Safety first Vehicle operation
& WARNING
The Ele
ctron ic Stabiliz ation Pr ogram i s ne verthele ss subje ct to the
laws of phy sic s. It is p articularl y important to pay attention to this
fa ct on wet and slipper y ro ad s. It i s therefore important th at you
alway s adapt your dr iving to the condit ion of the road and traffic
c ondition s. Do not allo w the in crea sed safety pro vided by the Ele c­
tronic Stabilization Program system to lull you into a ccepting
a ddition al safety ri sk s.
•
Electronic differential lock (EDL)
The elec tronic d ifferen tial lock moni tors the rotation al
s p eed of the drive wheels.
G en era l not es
The elect ronic d ifferential lock (EDU helps the ca r to start mov ing,
accelerate and c limb a grad ient on surfaces providing poor or
a lmost no grip . Without EDL, this would be difficult, if not impos ­
s ib le.
How the syst em works
The EDL operates automatical ly. It monitors the rotationa l speed of
t he drive wheels on an ax le with the he lp of the ABS senso rs
=> page 272. If a not iceable difference in rotational speed between
the drive wheels on one axle is detected (e.g. on slippery ground
on
one side),
the spinning w heel is bra ked, thereby transferring power
to the other drive wheel or wheels (a ll -whee l drive) . This is done up
t o a speed of ab out 60 mph (100 km/h). N oises from the brake
system signal that wheel spin is being control led .
Dri ving off
When driving off, always be sure to keep road conditions in mind as
you accelerate. I f one drive wheel spins because it is on a sur face
with less grip, gradual ly increase the pressure on the accelerator
pedal unt il the car star ts to move . The whee l less able to t ra nsfer
power spins.
.,,
Vehicle care Do-it-yourself service Technical data

-Intelligent technology
P:V:1--------=-- --=-=-------------
& WARNING
• Never let the vehi cle roll to a stop with the engine shut off .
• If the brake boo ster i s not working, for example when towing
your vehicle , or because the brake booster has so mehow been
damaged, the brake pedal must be pres sed considerably harder to
make up for the la ck of booster as sistan ce . •
Functioning of Anti-Lock Brake System (ABS)
AB S pre vent s th e wh eels fr o m lo ckin g up un der braking .
The ABS contributes effective ly to ve hicle control s ince it prevents
th e whee ls from
lo cking w hen t he brakes are a ppl ied. This mea ns
that the vehicle remains steerable and is less likely to skid.
With ABS you do not need to pump the brake . Just hold the brake
pedal down.
H owever, do not expect the ABS to shorten braking distance under
all cir cum stances. W hen drivin g on g ravel o r on new ly fallen s now
on top of icy surfac es, bra king distance may be even longer, there ­
fo re, unde r th ese circum stances, i t is especially i mporta nt th a t yo u
drive slow ly and with great care .
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
is reac hed . When this ha p pens, a pumping n oise can be hea rd.
If an indiv idua l wheel begins to rotate too s lowly in relation to
vehic le speed and tends to lock, the ABS automatica lly reduces
brake pressure to prevent that whee l from loc king .
T his automat ic adjustment process wil l cause a
slight vibration of
th e br ak e pe dal a nd some noises to ale rt you th at ve hic le sp eed
must be adapted to existing road and traffic conditions.
& WARNING
Although the ABS is very effe ctive , always remember that braking
capability is limited by tire traction. Alway s adjust your driving
speed a ccording to the road and traffi c conditions . Do not let the
extra safety afforded by the ABS tempt you into taking extra risks.
The ABS cannot overcome the laws of physics.
[ i ] Tips
• I f ABS is not funct io ni ng properl y, a wa rn ing li ght will co me o n.
See ~ page 21.
• I f a fault occurs in the A BS, the EDL is also not functioning. This
i s indica ted by the ABS wa rn ing l igh t.•
Brake assistant
The brake assis tant is desig ned to ach ieve the o ptim um
brakin g eff ec t.
The br ake assistan t helps to in cr eas e the effec tive b raki ng pow er
and thus to achieve a shorter stopping distance . If the driver
p re sses the b rake pe dal very q uick ly, the brake assistan t auto mati ­
ca lly boosts the brakin g force to the maximum level, up to th e point
whe re the a nti-lock b rake functi on (AB S) int ervenes to sto p the
w hee ls from loc king . You s hou ld t hen k eep th e br ake pedal pressed
until t he vehicle ha s braked to the required speed . The brake a ssis ­
t ant s witches itse lf off as soo n as you re lease t he bra ke pedal.
T he b rake assistant will not be ope rative if there is a malfunction in
th e ABS .
& WARNING
Please remember that the accident risk always increases if you
drive too fast , especially in corners or on a slippery road , or if you
follow the vehicle ahead of you too closely . Increased risk of an
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Operating instructions
M ax im um tra iler weig ht
A trailer for your vehicle is limited to a typ ical c lass 1 or class 2
trailer.
T ra ile r l oad d is tributi on
Be sure the load in the trailer is he ld securely in place to prevent it
from shifting forward, backward or s ideways .
Never a llow a pass enger to r ide in a trailer:::::, & in "Driving instruc­
t ions" .
Engin e coo lin g sys te m
Tow ing a trai ler makes the engine work harder. It is important that
the cooling system's performance is up to the additiona l load. Make
sure that the coo ling system has enough fluid .
Tire press ure
When towing a trailer, inflate the tires of your veh icle to t he co ld tire
pressure listed under "Full load" on the labe l located either on the
driver's side B -pil lar (visible when the door is open) or inside the fuel
filler flap . Inflate trailer tires to trai ler and tire manufacturers' spec­
ifications.
L ig ht s
The head light settings should be checked wit h the trai ler attached
before driving off. Check to make sure both vehicle and trai ler lights
are working properly .
Safe ty c ha in s
Be s ure trailer safe ty chains are properly connected from the trailer
to the hitch on the vehicle. Leave enough slack in the chains to
permit turning corners . When yo u insta ll safety chains, make sure
they will not drag on the road when you are driving.
T he chains should cross under the trailer tongue to prevent it from
dropping in case of separat ion from the hitch.
Controls and equip­
ment Safety first
Vehicle operation
0 Note
If you are go ing to tow a trai ler, you must activate the tra iler opera­
tion
mode :::::, page 189, "Towing a Trailer". •
Driving instructions
Driving with a trailer always requires extra care and
consideration.
To obtain the best possib le handling of ve hicle and trailer,
p lease note t he following :
- Do not tow a loaded trailer when your car itself is not
loaded.
- Be especia lly careful whe n passing other vehic les .
- Observe speed limits .
- Do not drive at the maximum permiss ible speed .
- Always apply brakes early.
- Monitor t he temperature ga uge .
W eight d istr ibu tion
Towing a loaded trailer with an empty car results in a highly
unstable d istribution of weight. If this cannot be avoided, drive at
very low speeds only to avoid the risk of losing steering control.
A "balanced" rig is easier to operate and control. This means that
t he tow vehicle should be loaded to the extent possible and permis ­
sib le, while keeping the trailer as light as possib le under the circum ­
stances . Whenever possible, transfer some cargo to the luggage
compartment of the tow vehicle whi le observing tongue load
requirements and vehicle loading considera tions .
.,,.
Vehicle care Do-it-yourself service Technical data

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0 Note
• Never try to remove dirt, mud or dust if the surface of the vehicle
is dry. Never use a dry cloth or sponge, since this could scratch your
vehicle 's paint or windows.
• Never wash your car in bright sunlight. Drops of water act as
magnifying lenses and may damage your paint.
• When you wash your car in the winter: if you rinse your vehicle
wi th a hose, be ca reful not to aim the stream of wa ter direc tly at
locks, or at door or hatch openings -they can freeze shut.
• Never use sponges designed to remove insects, or any kitchen
scouring sponges or similar products. They can damage your paint
finish .
• Never use a dry cloth or sponge to clean the headlights. Only use
wet cloths or sponges to prevent sc ratches . It is best to use soapy
water .
~ For the sake of the environment
In the interest of the environment, the vehicle should only be
washed in special wash bays. •
Washing your vehicle with a power washer
Cleaning the exterior of your car with a high-pressure
power washer is safe as long as you observe a few simple
rules.
- Before using the power washer, make sure you have read
and understood the WARNINGS :::>
& in "General infor­
mation" on
page 288.
- Always follow the operating instructions for the power
washer. - Make
sure that the jet on the spray hose produces a "fan
shaped spray".
- Do
not hold the spray nozzle too close to soft materials.
When cleaning the vehicle w ith a power washer always follow the
operating instructions. This applies particularly to the
operating
pressure
and the spraying distance. Maintain a sufficient distance
to soft materials such as rubber hoses and sound/vibration dead ­
ening materials (particularly on the underside of the engine hood).
Do not use a jet which sprays water in a
direct stream or one that
has a
rotating jet.
Water temperature should no t exceed 140 °F (60 °Cl.
& WARNING
Never wash tires with a jet that sprays water in a direct stream.
This could cause invisible damage to the tires and weaken them,
even if the spray is from a relatively long distance and for a short
time. Damaged and weakened tires can fail and cause accidents
and personal injury .
0 Note
To avoid damaging your vehicle, always make sure that there is
sufficient distance between the spray head and soft materials like
rubber hoses, plastic parts and sound-deadening materials . Never
aim the spray head at the same point for a long time. This also
applies to cleaning headlights and painted bumpers . Remember:
the closer the nozzle is to the surface of the material , the greater the
stress on the material. •

lll'ft __ T_ ir_e _s_ a_n_ d_ w_ h
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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. Tires are, however, one of the most important parts
of a vehicle, particu lar ly considering the comparatively smal l patch
of rubber on each tire that assures that all -important contact
between you, your vehic le and the road.
Maintaining the correct tire pressure, making sure that your vehicle
and its t ires do not have to carry more we ight than they can safely
handle, avoiding damage from road hazards and regularly
inspecting tires for damage inc luding cuts, slashes irregular wear
and overa ll condition are the most important things that you can do
to help avoid sudden tire failure inc luding tread separation and
blowouts.
Av oidin g dam age
If you have to drive over a curb or similar obstac le, drive very slowly
and as close as possib le at a right angle to the curb .
A lways keep chem ica ls including grease, oi l, gaso line and brake
flu id off the ti res.
Inspect t he t ires regu larly fo r damage (cuts, cracks or b listers, etc .l.
Remove any foreign bodies embedded in the treads .
Storing tire s
Mark tires when you remove them to indicate the direction of rota­
tion . This ensures you to be able to moun t them correctly w hen you
reinstal l them. When removed, the wheels or tires shou
ld be stored in a coo l, dry
and preferably dark place .
S tore tires in a vert ical pos it ion if they are not mounted on r ims, in
a horizonta l position if they are mounted on rims.
New tire s
New tires have to be broken in=> &.
The tread depth of new ti res may vary, according to the type and
make of tire and the tread pattern .
Hidden dam age
Damage to tires and rims is often not readily visible . If you notice
unusual vibration or the vehicle pu lls to one side, this may ind ica te
that one of the tires has been damaged . The tires must be checked
immediately by an authorized Audi dealer or qual ified workshop .
Unidir ec tiona l tir es
A unid irec tional tire can be identified by arrows on the sidewa ll, that
point in the direction the tire is designed to rotate. You must fo llow
t he specified directio n of rotation . Th is is necessary so that t hese
tires can deve lop their optimum characteristics regarding grip, road
noise, wear and hydrop laning resistance . For more information
=> page 357.
& WARNING
New t ires or tire s th at a re old , worn or d am aged cann ot pro vide
maximum control and braking ability.
• New tire s tend to be slipper y and mu st be bro ken in . To redu ce
the risk of lo sin g con tro l, a collision and seriou s per sonal injurie s,
dri ve w ith spe cial care f or the fi rst 350 mile s (560 km l.
• Driving wi th worn or damaged tir es can l ead to lo ss of control ,
sudd en tire f ailure , inc ludi ng a blowout and sudden defl atio n, .,_

Tires and wheels -
----------------
•
& WARNING (continued)
crashes and serious personal injuries . Have worn or damaged tires
replaced immediately.
• Tires age even if they are not being 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
low speed.
Glossary of tire and loading terminology
Accessory weight
means the combined weight (in excess of those standard items
which may be replaced) of automatic transmission, power steering,
power brakes, power windows, power seats, radio, and heater, to
the extent that these items are available as factory-installed equip­
ment (whether installed or not).
Aspect ratio means the ratio of the height to the width of the tire in percent.
Numb ers of 55 or lower indicate a low sidewall for improved
steering response and better overall handling on dry pavement.
Bead
means the part of the tire that is made of steel wires, wrapped or
reinforced by ply cords and that is shaped to fit the rim.
Bead separation
means a breakdown of the bond between components in the bead.
Cord
means the strands forming the plies in the tire.
& WARNING (continued)
• Never mount used tires on your vehicle if you are not sure of
their
"previous history." Old used tires may have been damaged
even though the damage cannot be seen that can lead to sudden
tire failure and loss of vehicle control.
• If you notice unusual vibration or if the vehicle pulls to one side
when driving, always stop as soon as it is safe to do so and check
the wheels and tires for damage.
•
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.
Curb weight
means the weight of a motor vehicle with standard equipment
including the maximum capacity of fuel, oil, and coolant, air condi­
tioning and additional weight of optional equipment.
Extra load tire
means a tire design to operate at higher loads and at higher infla ­
tion pressures than the corresponding standard tire. Extra load tires
may be identified as
"XL", "xi", "EXTRA LOAD", or "RF" on the side ­
wall.
Gross Axle Weight Rating
("GAWR")
means the load-carrying capacity of a single axle system, measured
at the tire -ground interfaces.
Gross Vehicle Weight Rating
( " GVWR")
means the maximum total loaded weight of the vehicle.
Vehicle care

_L--_T_ ir_e_ s_ a_ n_d _ w_ h_ e_e _l_s _________________________________________________ _
Groove
means the space between two adjacent tread ribs.
L oa d r atin g (code)
means t he m aximum load that a t ire is rated to carry for a given
inf lation pressure . You may not find this information on a ll tires
because it is not required by law.
M ax imum l oad r ating
means t he load rating for a tire a t the maximum permissib le infla­
tion pressure for that tire.
Maximum l oaded v ehi cle wei ght
means the sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capaci ty weight, and
(d) Product ion options weight
M ax imum (p er mis sibl e) infl ati on pr essure
means the maximum cold i nflation pressure to wh ic h a t ire may be
inflated. Also cal led "maximum inflation pressure."
Normal occ upant we ight
means 150 lbs. (68 ki lograms) times the number of occupants
seated in the veh ic le up to the total seating capacity of your vehicle.
Oc cupant distributi on
means distribution of occupants in a vehicle .
Outer di ameter
means the overal l diameter of an inf lated new tire.
O verall width
means the linear distance between the exteriors of the sidewa lls of
an infla ted t ire, includ ing elevat ions due to labe ling, decorat ions, or
protective bands or ribs .
Ply
means a layer of rubber -coated para llel cords.
P rodu cti on opt ion s we ig ht
means the co mbined weight of those insta lled regular product ion
options weighing over 5 lbs. (2.3 kg) in excess of those standard
items which t hey replace, not previously considered in curb weight
or accessory weight, inc luding heavy duty brakes, ride levelers, roof
rack, heavy du ty bat tery, and special trim .
Rad ia l pl y tir e
means a pneumat ic t ire in wh ich t he ply cords that extend to the
beads are laid at substantially 90 degrees to the centerline of the
t read .
Recomm ended infl ation pres su re
see :::::> page 325, "Cold tire inflat ion pressure".
R einforc ed tir e
means a tire des ign to operate at higher loads and at higher infla­
tion pressures than the corresponding standard tire. Reinforced
t ires may be iden tified as
"XL", "xi", "EXTRA LOAD", or "RF" on the
sidewa ll.
Rim
means a metal support for a tire or a tire and tube assembly upon
whic h the t ire beads are seated.
Rim di ame ter
means nominal diameter of the bead seat. If you change your whee l
size, you wi ll have to purchase new tires to match the new rim diam ­
eter.
Rim siz e design ation
means rim diameter and width.
Rim w idth
means nominal distance between rim flanges .

Tires and wheels -
-----------------------------
•
Sidewall
means that portion of a tire between the tread and bead.
Speed rating 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 338. You may not find this informa­
tion on all tires because it is not required by law.
The speed rating letter code, where applicable, is molded on the tire
sidewall and indicates the maximum permissible road
speeds=> &
in "Winter tires" on page 341.
Tire pressure monitoring system
means a system that detects when one or more of a vehicle's tires
are underinflated and illuminates a low tire pressure warning tell­
tale.
Tread
means that portion of a tire that comes into contact with the road.
Tread separation
means pulling away of the tread from the tire carcass.
Treadwear indicators (TWI)
means the projections within the principal grooves designed to give
a visual indication of the degrees of wear of the tread . See
=> page 335, "Tread Wear Indicator (TWI)" for more information on
measuring tire wear .
Uniform Tire Quality Grading
is a tire information system developed by the United States National
Highway Traffic Safety Administration (NHTSA) that is designed to
help buyers make relative comparisons among tires. The UTQG is
not a safety rating and not a guarantee that a tire will last for a
prescribed number of miles (kilometers) or perform in a certain way.
It simply gives tire buyers additional information to combine with
other considerations, such as price, brand loyalty and dealer recom- mendations
. Under UTQG, tires are graded by the tire manufac­
turers in three areas: treadwear, traction, and temperature resis­
tance . The UTQG information on the tires, molded into the
sidewalls.
U.S. DOT Tire Identification Number (TIN)
This is the tire's "serial number" It begins with the letters "DOT" and
indicates that the tire meets all federal standards . The next two
numbers or letters indicate the plant where it was manufactured,
and the last four numbers represent the week and year of manufac­
ture. For example,
DOT ... 2207 ...
means that the tire was produced in the 22th week of 2007 . The
other numbers are marketing codes that may or may not be used by
the tire manufacturer . This information is used to contact
consumers if a tire defect requires a recall.
Vehicle capacity weight
means the rated cargo and luggage load plus 150 lbs. (68 kilograms)
times the vehicle's total seating capacity as listed on the label located either on the driver's side 8-pillar or on the inside of the fuel
filler flap.
Vehicle maximum load on the tire
means that load on an individual tire that is determined by dis trib­
uting to each axle its share of the maximum loaded vehicle weight
and dividing by two.
Vehicle normal load on the tire
means that load on an individual tire that is determined by dis trib­
uting to each axle its share of the curb weight, accessory weight,
and normal occupant weight (distributed in accordance with table
below => page 328) and dividing by two. ..,.
Vehicle care