2015 AUDI S8 winter tires

90 On the road
facility for servicing as soon as possib le to
correct the malfunction.
Speed warning system
Introduction
The speed warning system helps you to stay
under a specified maximum speed.
The speed warning system warns you if you
are exceeding the maximum speed that you
have set . You will hear a warn ing tone when
your speed exceeds the stored value by ap­ proximately 3 mph (3 km/h). An indicator
light. (USA models) . (Canada models) in
the instrument cluster display also turns on at
the same time. The indicator light./.
turns off when the speed decreases below the
stored maximum speed.
Sett ing a threshold is recommended if you
wo uld like to be reminded when you reach a
certain maximum speed . Situations where you
may want to do so include driving in a country
with a general speed limit or if there is a
specif ied maximum speed for winter tires.
@ Tips
Even though your vehicle is equipped with
a speed warning system, you should still
watch the speedometer to make sure you
are not driving faster than the speed lim it.
Setting the threshold
You can set, change and delete the threshold
in the MMI.
.. Se lect : ICAR lfunction button> Car systems
control button > Driver assist > Speed warn­
ing.
You can set any threshold between 20 mph
(30 km/h) and 150 mph (240 km/h). Settings
can each be adjusted in increments of S mph
(10 km/h).
Cruise control
Switching on
The cruise control system makes it possible to
drive at a constant speed starting at 20 mph (30kmlh) .
0
•
~
0
Fig. 94 Control leve r with set b utton
Fig. 95 Display: Se lected speed
.. Pull the lever to position (D c::> fig. 94 to
sw itch the system on.
.. Drive at the speed you wish to set.
.. Press button @ to set that speed.
T he stored speed and the indicator light
II (US models) ;El (Canadian mode ls) ap­
pear in the instrument cluster display
c::> fig. 95 . The display may vary, depending on
the type of display in your veh icle .
T his information is also shown briefly in the
Head-up Display*.
Th e speed is kept constant via an engine out­
put adjustment or active brake intervent ion.
WARNING
-Always pay attention to traffic even when
the cruise control is switched on. You are
a.lways respons ible for your speed and
Ill-

202 Intelligent technology
Driving with your
quattro
With All Wheel Drive, all four wheels are driv­
en .
General inform ation
With All Wheel Drive, power is distributed to
all four wheels . This happens automatically
depending on your driving style and the road
conditions at the time . See also
c:;; page 197.
With the sport differential*, power d istribu­
tion to the rear wheels is variable and can be
adjusted with Audi d rive select*
c:;; page 108.
Always read and follow safety precautions
¢ .&,.
Winter tires
When driving in the winter , your vehicle with
A ll Wheel Drive has an advantage, even with
regular tir es. In winter road conditions it may
be advisable to mount winter tires (or all-sea­
son tires) for improved driveability and brak­ ing: these tires must be mounted on
all four
wheels.
See also ¢ page 260, Winter tires.
Snow chains
Where snow chains are mandatory on certa in
roads, this normally a lso applies to vehicles
with A ll Wheel Drive
c:;, page 261, Snow
chains .
Replacing wheels/tires
Vehicles with All Wheel Dr ive must always
have tires of the same size. Also avoid ti res
with different tread depths. For details see
page
c:;, page 256, New tires and replacing
tires and wheels .
Off-Road driving?
Your Audi does not have enough ground clear­
ance to be used as an off-road vehicle. It is
therefore best to avoid rough tracks and un ­
even terrain as much as possible. Also refer to
c:;; page207.
A WARNING
Always adjust your driving to road and traf­
f ic conditions. Do not let the extra safety
afforded by All Wheel Drive tempt you into
taking extra risks.
- Although the All Wheel Drive is very ef­
fective, always remember that braking
capacity is lim ited by tire traction. You
should therefore not drive at excessive
speeds on icy or slippery road surfaces.
- On wet road surfaces, be careful not to
drive too fast because the front wheels
could begin to slide on top of the water
(aquaplaning) . If this should occur, you
will have no warning from a sudden in­
crease in eng ine speed as with a front­
wheel drive vehicle. Always drive at speeds which are suited to the road con­
ditions - risk of crash .
Energy management
Starting ability is optimized
Energy management controls the distribution
of electrical energy and thus optimizes the
availability of electrical energy for starting
the engine .
If a vehicle with a conventiona l ene rgy system
is not driven for a long period of time, the bat­
tery is discharged by idling current consumers
(e .g. immobilizer). In certain circumstances it
can resu lt in there being insufficient energy
available to start the engine .
Intelligent energy management in your vehi­
cle handles the distribution of e lectrica l ener­
gy. Starting ability is markedly improved and
the life of the battery is extended.
Basically, energy management consists of
battery diagnosis , idling current manage­
ment
and dynamic energy management.
Battery diagnosis
Battery diagnosis continuously determines
the state of the battery. Sensors determine
battery voltage, battery current and battery ..,.

24 6 T ire s and whee ls
- 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.
- If you notice unusual vibration or if the
vehicle pulls to one side when driving, al­
ways stop as soon as it is safe to do so and check the wheels and tires for dam­
age.
(D Note
- Please note that summer and winter
tires are designed for the cond itions that
a re typ ica l in those seasons. Aud i recom­
mends using w inter t ires d uring the win-
Glossary of tire and loading terminology
Accessory weight
means t he 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 available as factory-installed equip­
ment (whether installed or not).
Aspect ratio
means t he ratio of the height to the width of
the tire in percent. Numbers of 55 or lower in­
d icate a low sidewall for improved steer ing re­
sponse and better overall handling on dry pavement .
Bead
means the pa rt of the tire t hat is made of
steel wires, wrapped or 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 t he strands forming the plies in the
tire. ter months.
Low tempe ratu res signifi­
cantly decrease the elasticity of summer
tires, which affects traction and braking ability. If summer tires are used in very
co ld temperatures, cracks can form on
the tread bars, resu lting in permanent
tire damage that can cause loud driving noise and unbalanced tires. Aud i is not
responsib le for this type of damage.
- Burn ished, polished or chromed rims
must not be used in winter weather. The
surface of the rims does not have suff i­
c ien t corrosion protect io n for this and
cou ld be pe rmanently damaged by road
salt or simi lar substances. This damage
is not covered by war ranty.
Cold tire inflat ion pre ssure
means the t ire press ure recommended by the
vehicle manufacturer for a tire o f a des ignated
size that has not been driven for more than a
coup le of miles (ki lometers) at low speeds in
the three hour period before the tire press ure
is measured or adjusted.
Curb weight
means the weight of a motor vehicle w ith
standard equipment including the maximum
capacity of fuel, o il, and coolant, air cond i­
tion ing and additional weight of optiona l
equipment.
E x tra load tire
means a tire design to operate at higher loads
and at higher inflation pressures than the cor­
responding standard tire. Extra load tires may
be identified as "XL", "xl", "EXTRA LOAD", or
"RF" on the sidewall.
Gross A xle Weight Rating ("GAWR ")
means the load-carrying capacity of a single
axle system, measured at the tire-ground in -
terfaces.
IJ>,

248 Tires and wheels
Speed rating (letter code)
means the speed at wh ic h a tir e is des igned to
be d riven for extended per io d s of t ime. The
ratings range from 93 mph (150 km/h) to
186 mph (298 km/h)
¢ page 257. You may
not find this in format ion on all tires because
it is not required by law.
The speed rating letter code, w here a pplica­
b le, is molded on the tire s idewa ll and indi­
cates the maxim um permissible road speeds
¢ &. in Winter tires on page 261.
Tire pressure monitoring sy stem*
means a system tha t d etects when one or
mo re of a vehicle's t ires are under inflated and
i llum inates a low t ire p ress ure warn ing te ll­
tale.
Tread
means t hat port ion of a tire tha t comes into
con tact w it h t he road.
Tread separation
means pull ing away of the t read from the t ire
car cass .
Treadwear indicators (TWI)
means t he projections withi n the pr inc ipal
g rooves designed to give a v isua l ind ication of
the deg rees of wea r of the tre ad . See
¢
pag e 255, Tread W ear Indicator (TWI) for
mo re inf ormat io n on measu ring tire we ar.
Uniform Tire Quality Grading
is a tire i nfo rmation system developed by the
United States Nat io nal Highway Traffic Safety
Admin istration (N HTSA) that is designed to
h e lp buye rs make re lative compa risons among
tires. The UT QG i s no t a safety r ating and no t a
g uar antee t hat a t ire will las t fo r a presc ribed
n umber of m iles (kilome ters) or pe rform in a
certain way. It s imply gives ti re bu ye rs addi­
tional information to combine with other con -s
iderations, such as p rice , brand loya lty and
dealer recommendations. Un der UTQ G, tires
are grade d by the t ire manufacturers in three
areas : treadwea r, traction, and temperature
resistance. The UTQG informat ion on the tires,
molded into the sidewalls .
U.S. DOT Tire Identification Number (TIN )
This is the tire's "se ria l numbe r" It begins
with the letters "DOT" and ind icates that the
t ire meets all federa l standards . The next two
numbers or letters ind icate the plant where it
was ma nufactu red, and the last four numbe rs
r eprese nt the week and year of ma nufact ure.
Fo r exampl e,
DOT ... 2214 ...
means that the tire was produced in t he 22nd
wee k of 2014. The ot her numbers are market­
ing codes that may or may not be used by the
t ire manufacturer. This information is used to
contact consumers i f a tire defect requires a
r ecall .
Vehicle capacity weight
means the rated cargo and luggage load plus
150 lbs. (68 k ilograms) times the vehicle's to­
ta l seating capacity as listed on the label lo­
cated on the driver's side B-pilla r.
Vehicle maximum lo ad on the tire
means that load on an individua l tire that is
determined by distributing to eac h axle its
share of the maxim um loaded vehicle weight
and divid ing by two .
Vehicle normal load on the tire
means that load on an individua l t ir e that is
determined by distributing to eac h ax le its
share of the curb weight, accessory weight,
and normal occ upant weig ht (d istr ibuted in
accorda nce wit h tab le below ¢
page 249)
and divid ing by two .

,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1'1 ,...., 1.1'1 ,....,
contribution to good road holding and safe
handling when in good condition and properly
inflated
¢ .&. .
We recommend that all work on t ires and
wheels be performed by an authorized A udi
dealer. They are familiar with recommended
procedures and have the necessary spec ial
too ls and spare parts as we ll as the proper fa ­
cilities for dispos ing of the old tires .
Authorized Audi dealers have the necessary information about techn ica l requ irements for
installing or changing tires and r ims.
R eplacing t ires and wheel s
Tires shou ld be rep laced at least in pairs and
not individua lly (for example both front tires
or both rear tires together).
Be s ure to read and heed the information to
the tire pressure monitoring system*
¢page 263.
Always buy rep lacement radial tires that have
the same specifications as the t ires approved
for your ve hicle by Audi. Replacement tires
must always have the same load rating speci ­
fication as the original equipment or approved
optional tires listed in the table¢
page 249.
Audi-approved specification tires are specially
matched to your vehicle and its load limits,
and can contribute to the important road hold­
ing, driving character istics, and safety of the
veh icle. The table(¢
page 249) lists spec ifica­
tions of the t ires approved for the Audi mod­
e ls covered by your Owner's Literature .
The tire pressure labe l located on dr iver 's side
B-pillar
( ¢ page 249, fig. 209) lists the speci­
fications of the orig inal equipment tires in­
stalled on your veh icle at the time it was man­
ufactured .
Federal law requires t ire manufacturers to
p lace standard ized information on the s ide­
wall of all tires ¢
fig. 212 . This information
i dent ifies and desc ribes the fundamental
characterist ics, the quality grade of the tire
and a lso provides a tire ide ntificat io n number
Tire s an d wheel s 257
for sa fety standard certification and in case of
a reca ll.
Tire specifications
Knowledge of tire specifications makes it eas­
ier to choose the co rrec t tires . Radial ti res
have the tire specifications marked on the
sidewa ll, for examp le:
255 /45 R 19 104 H
This co nta ins the following information :
P Indicates the tire is for passenger cars
(where app licab le)
255 Nom inal tire width i n mm of the tire
from sidewall edge to sidewall edge. In
general, the larger the number, the wider
the tire
45 Height/w idth ratio in percent (aspect ra -
t io)
R Tire construct ion: Radial
1 9 Rim diameter code (i n inches)
104 Load ra ting code
H Speed ra ting letter code
XL (or "xl", "EXTRA LOAD" or "RF") Indicates
t h at the t ire is a "Reinfo rced" or an " Ext ra
Load " tir e
M+S (or "M/S") Indicates that the ti re has
some mud and snow capab ility
The tires could also have the informat ion of
direction of rotat ion ¢
page 245 .
Tire manufacturing d ate
The manufact uring date is also indicated on
the tire sidewall (possibly only on the
inner
s ide of the wheel):
"DOT ... 2214 .. . " means, for example, the tire
was produced in the 22nd week of 2014.
Speed rating (letter code )
The speed rating le tter code on the whee ls in­
dicates the maximum permiss ible road speeds
¢ .&. in Winter tires on page 261.
P up to 93 mp h (150 km/h)
Q up to 99 mph (158 km/h)
R up to 106 mph (170 km/h)
S up to 110 mph (180 km/h)
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,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1"1 ,...., 1.1"1 ,....,
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
vehicles -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
vehicles that were equipped with them at the factory . The vehicle must have a
chassis designed for run flat tires. Incor­
rect use of run flat tires can lead to vehi­
cle damage or accidents. Check with an
authorized 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. Mixing tire types is not permit­
ted.
(D Note
- For technical reasons, it is not generally
possible to use the wheel rims from oth-
Tires and wheels 259
er vehicles. This can hold true for wheels
of the same vehicle type.
- 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
- Tract ion AA A B C
- Temperature AB C
Quality grades can be found where applicable
on the tire side wall between tread shoulder
and maximum section width
c;, page 256,
fig. 212.
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 ISO 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.
ll-
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260 Tire s and wheel s
Traction
The traction grades, from highest to lowest,
are AA, A, Band
C. T hose grades represent the
tire's ability to stop on wet pavement as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance
c:> .&. .
Te mp eratu re
The temperature grades are A (the highest),
B, and
C, representing the t ire's resistance to
the generat ion of heat and its ability to dissi­
pate heat when tested under con trolled cond i­
tions on a specified i ndoor laboratory test
wheel.
Sustained high temperature can cause the material of the tire to degenerate and reduce
tire life, and excessive temperature can lead
to sudden tire failure
c:> ,& .
The grade C corresponds to a level of perform­
ance which all passenger car tires must meet under the Federa l Motor Veh icle Safety Stand­
ard No . 1 09 . Grades Band A represent h igher
l eve ls of pe rformance on the laboratory test
wheel than the m inimum required by law.
.&_ WARNING
T he traction grade assigned to this t ire is
based on stra ight-ahead braking traction
tests, and does not include acceleration,
cornering, hydrop laning o r peak traction
character istics.
A WARNING
The temperature grade for this t ire is es ­
tablished for a t ire that is properly inflated
and not ove rloaded. Excessive speed, un­
derinflation, or excessive loading, either
separately or in combination, can cause
heat buildup and possible ti re fa ilu re.
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Winter tires
Winter tires can improve vehicle handling on
snow and ice . At temperatures below 45 °F
(7 °C) we recommend changing to winter
tires.
In some heavy snow areas, local governments
may require true w inter o r "snow" t ires , those
with very deeply cut tread . Th ese tires should
o n ly be used in pairs and be installed on a ll
f o ur wheels . Make sure you p urch ase snow
t ir es that are the same size and cons truction
type as the othe r tires on yo ur vehicle.
If your vehicle i s equ ipped w ith all-whee l
drive, this will improve tra ction during w inte r
driv ing, even with the standard tires . Howev ­
er, we strongly recommend that you always
equip all four wheels on your vehicle w ith cor­
rect ly fitted winter tires or all-season t ires,
when winter road condit ions are expected.
This also improves the veh icle 's brak ing per­
formance and reduces stopping d istances .
Summer tires provide less grip on ice and
snow.
Winter tires (snow tires) must always be fitted on all fo ur whee ls .
As k your au thori zed A udi dealer or qualified
workshop for permit ted
winter tire size s. Use
only radial winter tires .
Winter tires lose their effec tivenes s whe n the
tread is wo rn down to a depth o f 0 .1 57 inch
(4 mm) .
Only d rive w ith w inter t ires under w inte r co n­
di tions. S umme r tir es handle be tte r whe n
the re is no snow o r ice on the roa ds an d the
temperatu re is above 45 °F (7 °C) .
If you have a flat ti re, see notes on spare
whee l
c:> page 256.
Please a lways remember that winter tires may
have a lowe r speed rating than the tires o rigi­
nally i nstalled on your vehi cle at the time it
was manuf actu red. P lease see
c:> page 257,
Speed ra ting (Letter code) fo r a lis ting o f the
speed rating lette r codes and the max imum
speed at which the tires can be driven . ..,.

,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1'1 ,...., 1.1'1 ,....,
The speed rating letter code (c::> page 248) is
on the side wall of the tire
c::> page 256.
A WARNING
Winter tires have maximum speed limits
that may be lower than your vehicle's max­
imum speed . Always know the maximum
speed before driving off. Never drive faster
than the speed permitted for your specific
winter tires . This will cause damage to the
tires leading to an accident and serious
personal injury to you and your passen­
gers.
A WARNING
Driving faster than the maximum speed
for which the winter tires on your vehicle
were designed can cause tire failure in­ cluding a blowout and sudden deflation,
loss of control, crashes and serious per­
sonal injuries . Have worn or damaged tires
replaced immediately.
- Winter tires have maximum speed rating
that may be lower than your vehicle's
maximum speed .
- Never drive faster than the speed for
which the winter or other tires installed
on your vehicle are rated .
A WARNING
Always adjust your driving to the road and
traffic conditions. Never let the good ac­
celeration of the winter tires and all-wheel
drive tempt you into taking extra risks . Al­
ways remember :
- When braking, an all-wheel drive vehicle
handles in the same way as a front drive
vehicle.
- Drive carefully and reduce your speed on
icy and slippery roads, even winter tires
cannot help under black ice conditions.
@l For the sake of the environment
Use summer tires when weather condi­
tions permit. They are quieter, do not wear
as quickly and reduce fuel consumption.
-
Tires and wheels
Snow chains
Snow chains may be fitted only to the front
wheels , and only to certain tire sizes. Ask your
authorized Audi dealer on which tire sizes
snow chains can be used.
If you are going to use snow chains, then you
must install them on the front wheels at
least.
The snow chains must have low-profile links
and must not be thicker than 0.4 inch
(10,S mm) , including the lock.
Remove wheel center covers and trim discs
before putting snow chains on your vehicle
c::> (]) . For safety reasons cover caps must then
be fitted over the wheel bolts. These are avail­
able from authorized Audi dealers.
A WARNING ,..__
Using the wrong snow chains for your vehi­
cle or installing them incorrectly can in­
crease the risk of loss of control leading to
serious personal injury.
- Snow chains are available in different
sizes . Always make sure to follow the in­
structions provided by the snow chain manufacturer .
- When driving with snow chains never
drive faster than the speed permitted for
your specific snow chains .
- Always observe local regulations.
(D Note
- Remove snow chains before driving on
roads not covered with snow to avoid
damaging tires and wearing the snow
chains down unnecessarily.
- Snow chains, which come into direct con­
tact with the wheel rim, can scratch or
damage it. Therefore, make sure that the
snow chains are suitably covered . Check
the position of the snow chains after
driving a few yards and correct if neces­
sary. Follow the instructions from the
snow chain manufacturer when doing so.
- If the Adaptive Air Suspension should
malfunction, do not mount or use snow ..,.
261
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