AUDI A4 2008 B8 / 4.G Owners Manual
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Wheels and tyres269
– The tyre pressures should only be checked when the
tyres are cold. The slightly raised pressures of warm tyres
must not be reduced.
– The pressures must be altered to suit major changes in
the load being carried.
– Avoid fast cornering and hard acceleration.
– Inspect the tyres for irregular wear from time to time.Tyre pressure and vehicle loading
The tyre pressure must be adjusted according to the load the vehicle
is carrying. We recommend adhering to the tyre pressure specifica-
tions for a maximum load. The tyre inflation pressures are listed on
a sticker on the end face of the driver's door ⇒page 268, fig. 261.
However, if you prefer an extra-smooth ride and the vehicle is not
fully loaded, you can select the tyre pressure for a normal load (no
more than three people travelling in the vehicle). However, should
you wish to drive with a full load you must increase the tyre pressure
to the specified maximum.
Under-inflation or over-inflation will reduce the life of the tyres
considerably and also impair the car's handling. Correct inflation
pressures are very important, especially at high speeds. The pres-
sures should therefore be checked at least once a month and before
starting a journey.
Do not forget the spare wheel* when checking the tyre pressures.
Keep the spare tyre inflated to the highest pressure required for the
Fast cornering, heavy acceleration and hard braking (squealing
tyres) all increase tyre wear.Wheel balancing
The wheels on new vehicles are balanced. However, various factors
encountered in normal driving can cause them to become unbal-
anced, which results in steering vibration.
Unbalanced wheels should be rebalanced, as they otherwise cause
excessive wear on steering, suspension and tyres. A wheel must
also be rebalanced when a new tyre is fitted or if a tyre is repaired.
Incorrect wheel alignment
Incorrect wheel alignment causes excessive tyre wear, impairing the
safety of the vehicle. If you notice excessive tyre wear, contact your
Always adapt the tyre pressure accordingly when the vehicle
Under-inflated tyres flex more and can overheat at continuous
high speeds. This can cause tread separation and tyre blow-out,
which could result in an accident.For the sake of the environment
Under-inflated tyres will increase the fuel consumption.
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Wheels and tyres 270Tread wear indicators
The tread wear indicators show the condition of the tyre
treads.The original tyres on your vehicle have 1.6 mm high “tread wear
indicators” ⇒fig. 262 running across the tread. Depending on the
make, there will be 6 to 8 of them spaced at equal distances around
the tyre. Markings on the tyre sidewall (for instance the letters “TWI”
or a triangle) indicate the positions of the tread wear indicators.
The minimum tread depth required by law in Germany is 1.6 mm
(measured in the tread grooves next to the tread wear indicators).
Other specifications may apply in export countries.
To avoid putting safety at risk, the tyres must be replaced at the
latest when the tread is worn down to the tread wear indicators.•
Especially in difficult driving conditions such as wet or icy
roads, it is important that the tyres have sufficient tread depth.
The tread depth should same on the tyres of both the front and the
The decrease in driving safety due to insufficient tread depth is
particularly evident in vehicle handling, when there is a risk of aquaplaning in deep puddles of water and when driving through
corners. Braking is also adversely affected.
The speed has to be adapted accordingly, otherwise there is a
risk of losing control over the vehicle.
Changing wheels roundTo ensure that the wear is equal on all tyres the wheels should be
changed round from time to time according to the system
⇒fig. 263. All the tyres will then last for about the same time.Replacing wheels and tyres
It is important to use the correct wheels and tyres when
replacement is necessary.– All four wheels must be fitted with tyres of the same type,
size (rolling circumference) and preferably the same
– If possible, tyres should be replaced at least in pairs and
not individually (i.e. both front tyres or both rear tyres
Fig. 262 Tyre tread:
Tr e a d w e a r i n d i c a t o r s
Fig. 263 Changing
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Wheels and tyres271
– Never use tyres whose actual size exceeds the dimen-
sions of the factory-approved makes of tyre.
– If you wish to fit the vehicle with non-standard rims or
tyres, it is advisable to consult an Audi dealer before
purchasing them.The tyres and wheel rims are an essential part of the vehicle's
design. The tyres and rims approved by Audi are specially matched
to the characteristics of the vehicle and make a major contribution
to good roadholding and safe handling ⇒.
The sizes of the rims and tyres approved for your vehicle are listed
in the vehicle's documents (e.g. EC Certificate of Conformity or COC
3)). The vehicle documents vary depending on the
country of residence.
Understanding the tyre designations makes it easier to choose the
correct tyres. For example, radial ply tyres have the following tyre
designations marked on the sidewall:
225 / 50 R 17 94 Y
This contains the following information:
The manufacturing date is also indicated on the tyre sidewall
(possibly only on the inner side of the wheel):
DOT ... 1006...means, for example, that the tyre was produced in the 10th week of
Please note that with some types of tyres, the actual tyre size can
differ from the nominal size marked on the tyre (for instance 225/50
R 17 94 Y), and there may be significant differences in the contours
of the tyres, even though the tyres are marked with the same
nominal size designation. When replacing the tyres, it is therefore
important to make sure that the actual size of the new tyres does
not exceed the dimensions of the factory-approved makes of tyre.
Failure to observe this requirement can affect the clearance needed
for the tyres. This could result in contact between the tyres and
suspension components or bodywork. The brake lines could also be
damaged and the vehicle's safety could be severely impaired ⇒.
When using tyres with the maximum permitted nominal dimen-
sions, this can also void the vehicle's registration.
If you use tyres that are approved by Audi you can be sure that the
actual tyre dimensions will be correct for your vehicle. If you decide
to fit a different type of tyre, you must obtain the appropriate manu-
facturer's certificate from the tyre retailer to confirm that the tyres
are suitable for your vehicle. Keep this certificate in a safe place.
Your local Audi dealer will be able to advise you on which tyres may
be fitted to your vehicle.
On vehicles with four-wheel drive, all four tyres must always be
fitted with tyres of the same type, make and tread pattern, as other-
wise the driveline can be damaged by continuous variations in the
wheel speeds. For the same reason, only use a spare wheel* with
the same tyre dimensions as the normal road wheels.
It the spare tyre* is not the same type as the tyres fitted on the car
(for example if the car has winter tyres or wide-section tyres) you
should only use the spare tyre if a puncture occurs, and then only
for a short period of time. In this case, please drive with extra care.
Refit the normal road wheel as soon as possible.
It is best to have all servicing of wheels and tyres performed by a
qualified workshop. They have the necessary special tools and
3)COC = certificate of conformity
Tyre width in mm
Height/width ratio in %
Tyre construction: Radial
Rim diameter in inches
Load rating code
Speed rating code letter
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Wheels and tyres 272replacement parts, trained personnel and facilities for disposing of
the old tyres.
It is very important to ensure that the tyres you have chosen
have adequate clearance. When selecting replacement tyres, do
not rely entirely on the nominal tyre size marked on the tyre; with
some makes of tyre the effective tyre size can differ significantly
from the nominal dimensions, even though the tyres have the
same size designation. Inadequate tyre clearance can result in
damage to the tyres or the vehicle, causing a serious safety risk. It
may also invalidate the vehicle's type approval for use on public
Please ask your Audi dealer or qualified workshop whether run
flat tyres can be used on your vehicle. Unauthorised use of these
tyres can invalidate the vehicle's type approval for use on public
roads. Furthermore, this could cause damage to your vehicle and
possibly also result in an accident.
Avoid running the car on tyres that are more than 6 years old.
If you have no alternative, you should drive slowly and with extra
care at all times.For the sake of the environment
Old tyres must be disposed of according to the laws in the country
Never mount used tyres if you are not sure of their previous
For technical reasons it is not normally possible to use wheel
rims from other vehicles. In some cases this also applies to rims
from other vehicles of the same model.
The wheel bolts are designed to suit the rims on your car.The wheel bolts are matched to the rims. When installing different
wheels (for instance wheels with winter tyres) it is important to use
the correct wheel bolts with the right length and correctly shaped
bolt heads. This is essential for the secure fit of the wheels and for
the proper function of the brake system.
Audi dealers have full information on the technical requirements
when installing or changing tyres, rims or wheel trims.
The wheel bolts should be clean and turn easily.
A special adapter is required to turn the anti-theft wheel bolts*
⇒page 292.Winter tyres
Winter tyres will significantly improve the car's handling
in winter road conditions.–Use only radial ply winter tyres.
– Winter tyres must be fitted on all four wheels.
– Only use winter tyres of the correct type approved for
– Please note that the maximum permissible speed for
winter tyres may be lower than for summer tyres.
– Also note that winter tyres are no longer effective when
the tread is worn down.
– After fitting the wheels you must always check the tyre
pressures. The correct tyre pressures are listed on the
sticker on the end face of the driver's door.
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Wheels and tyres273
Technical data In winter road conditions winter tyres will considerably improve the
car's handling. Due to their type of construction (width, rubber
compound, tread pattern), summer tyres give less grip on ice and
snow. This applies particularly to vehicles equipped with wide
section tyres or high speed tyres (code letters H, V or Y on the side-
Only use winter tyres of the correct type approved for your vehicle.
The sizes of the winter tyres approved for your vehicle are listed in
the vehicle's documents (e.g. EC Certificate of Conformity or COC
4)). The vehicle documents vary depending on the
country of residence. Also refer to ⇒page 270, ⇒page 270.
Winter tyres are no longer fully effective when the tread is worn
down to a depth of 4 mm.
The performance of winter tyres is also severely impaired by ageing,
even if the tread is still much deeper than 4 mm.
Winter tyres are subject to the following maximum speed limits
according to speed rating code letter: ⇒
In Germany vehicles capable of exceeding these speeds must have
an appropriate sticker attached so it is visible to the driver. Suitable
stickers are available from Audi dealers and specialist retailers.
Please note regulations to this effect in your country.“All-weather” tyres can also be used instead of winter tyres.
Using winter tyres with V-rating
Please note that the generally applicable 240 km/h speed rating for
winter tyres with the letter "V" is subject to technical restrictions;
the maximum permissible speed for your vehicle may be signifi-
cantly lower. The maximum speed limit for tyres with a V-rating
depends directly on the maximum axle weights for your car and on
the listed weight rating of the tyres being used.
It is best to contact an Audi dealer to check the maximum speed
which is permissible for the V-rated tyres fitted on your car on the
basis of this information.
Exceeding the maximum speed permitted for the winter tyres
fitted on your car can cause tyre failure, resulting in a loss of
control of the vehicle – risk of accident.
For the sake of the environment
Summer tyres should be fitted again as soon as possible; they give
better handling on roads which are free of snow and ice. Summer
tyres produce less rolling noise, do not wear down as quickly and,
most importantly, reduce fuel consumption.Snow chains
Snow chains will improve the vehicle's handling on snow-
covered roads.– Snow chains can be used on the front wheels only.
– Keep your speed below 50 km/h.Snow chains will improve braking ability as well as traction in winter
4)COC = certificate of conformitySpeed rating code letter
⇒page 270, ⇒page 270
Maximum speed limit
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Wheels and tyres 274For technical reasons snow chains may only be used on tyres with
certain wheel rim/tyre combinations.
Only use snow chains with fine-pitch links. The links must not
protrude more than 13.5 mm from the tyres (including tensioner).
Remove the chains when roads are free of snow. Otherwise they will
impair handling, damage the tyres and wear out very quickly.
Four-wheel drive: where snow chains are compulsory on certain
roads, this normally also applies to cars with four-wheel drive. Snow
chains may only be fitted to the front wheels (also on vehicles with
four-wheel drive).Run flat tyresApplies to vehicles: with run flat tyresIntroduction
Run flat tyres allow you to continue your journey in the
event of a loss of tyre pressure.Run flat tyres have reinforced sidewalls which support the tyre in
the event of a loss of pressure.
Run flat tyres must only be used on vehicles which were already
factory-fitted with these tyres and which also have a tyre pressure
Run flat tyres can be identified by the marking “RSC” (Runflat
System Component) on the sidewall.If you change the tyres on your vehicle from regular tyres to run flat
tyres or vice-versa, the control unit must be reprogrammed by an
Audi dealer or other qualified workshop.
What are the benefits of run flat tyres?
Run flat tyres ensure that you remain mobile, even in the event of a
loss of tyre pressure. In favourable conditions these tyres have an
operating range of at least 30 km, however the vehicle must not be
driven faster than 80 km/h ⇒ in “Driving with run flat tyres” on
The tyre pressures are constantly checked by the tyre pressure
monitoring system. When the run flat system becomes active
(centre display), it is still the driver's responsibility to check the
tyre(s) affected and to decide whether it is possible to continue
driving. Also refer to ⇒page 275, “Driving with run flat tyres”.
When is it no longer possible to continue driving with
the help of the run flat tyres?
If the Electronic Stabilisation Program (ESP) is out of operation
or is triggered continuously.
If the tyre pressure monitoring system is out of operation.
If one of the tyres has been severely damaged in an accident, etc.
If a tyre has been badly damaged there is a risk that parts of the
tread can be thrown off and cause damage to the fuel lines, brake
pipes or fuel filler.
You must stop driving if severe vibrations occur, or if the wheel
starts overheating and gives off smoke.
You must also stop driving if damage to the tyres (e.g. tears in
the sidewalls) becomes apparent.
Please ask your Audi dealer or qualified workshop whether run flat
tyres can be used on your vehicle. Unauthorised use of these tyres
can invalidate the vehicle's type approval for use on public roads.
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Wheels and tyres275
Technical data Furthermore, this could cause damage to your vehicle and
possibly also result in an accident.
If you cannot continue driving even with run flat tyres please
obtain professional assistance.
You should obtain professional assistance if you are in any doubt
regarding the rims and tyres for your vehicle.
Applies to vehicles: with run flat tyresDriving with run flat tyres
Please remember that the vehicle's handling will be
impaired.Driving a vehicle with a deflated tyre, or with insufficient
tyre pressure, is an abnormal situation. However, since the
handling of a vehicle equipped with run flat tyres is only
slightly impaired, it is important to remember that you are
driving with a deflated tyre. If you have to make use of the
run flat system please remember the following points:
– The Electronic Stabilisation Program (ESP) must be
–Do not exceed 80km/h ⇒.
– Anticipate the traffic situation well in advance.
– Be careful when accelerating.
– Avoid unnecessary braking and steering manoeuvres.
– Reduce speed in good time before corners and potential
Please refer to ⇒page 274, “ When is it no longer possible to
continue driving with the help of the run flat tyres?”
Effects on handling when driving with defective tyres
If one of the front tyres is defective, your vehicle will tend to pull
slightly towards that side and braking performance will be
A defective rear tyre will also make the vehicle pull slightly to one
side, and the braking response will again be slightly impaired.
These effects will be most noticeable when driving in a corner.
When using the run flat system the changes in vehicle handling
will be noticeable when braking, in corners and during fast accel-
The maximum permitted speed of 80 km/h is subject to road
and weather conditions. Always observe the relevant rules and
regulations. Run flat tyres allow you to continue your journey in
the event of a loss of tyre pressure. However, the driver remains
responsible for the safety of the vehicle and for restoring the
correct tyre pressure and having defective parts replaced
⇒page 276. For these reasons you should always adjust your
driving to suit the circumstances.Caution
We recommend that you drive with great care when making use of
the run flat system. Avoid abrupt manoeuvres.
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Wheels and tyres 276Applies to vehicles: with run flat tyresRenewing defective components on run flat tyres
The run flat tyres have been specially developed for your
vehicle and matched to its requirements.Use and combine only the approved run flat tyres and rims. It is not
permissible to combine standard wheels and run flat tyres ⇒.
If you have to drive with low tyre pressure or with a completely
deflated tyre, you should always take the vehicle to an authorised
qualified workshop and have the defective parts inspected and the
We recommend that you have the run flat tyre renewed and
also have the rim checked by a qualified workshop to identify any
Using tyres or rims which have not been approved can cause
damage to the vehicle. Vehicle handling can be impaired and
driving safety can no longer be guaranteed. This can also void the
vehicle's certification for use on public roads.Note
Run-flat tyres can be repaired with the TMS ⇒page 285.
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Accessories and modifications to the vehicle277
Accessories and modifications to the vehicleAccessories and replacement partsAlways ask your dealer or specialist retailer for advice
before purchasing accessories and replacement parts.Your car is designed to offer a high standard of active and passive
safety. For this reason, we recommend that you ask an Audi dealer
for advice before fitting accessories or replacement parts. Audi
dealers have the latest information from the manufacturer and can
recommend accessories and replacement parts which are suitable
for your requirements. They can also answer any questions you
might have regarding official regulations.
We recommend you to use only Audi accessories and Audi Genuine
®. Audi has tested these parts and accessories for suitability,
reliability and safety. Audi dealers have the necessary experience
and facilities to ensure that the parts are installed properly.
Although the market is constantly scrutinised, Audi cannot judge or
assume responsibility for the reliability, safety and suitability of
non-genuine products - even though in some instances, these parts
may have been approved by an officially recognised technical
testing authority or accompanied by an official approval certificate.
Any retro-fitted equipment which has a direct effect on the vehicle
and/or the way it is driven (e.g. cruise control system or electroni-
cally-controlled suspension) must be approved for use in your
vehicle and bear the e mark (the European Union's approval
If any additional electrical components are fitted which do not serve
to control the vehicle itself (for instance a refrigerator box, laptop or
ventilator fan, etc.), these must bear the CE mark (manufacturer
conformity declaration in the European Union).
Never attach accessories (such as cup holders or telephone
brackets) to the surfaces covering the airbag units or the areas
around the airbags: this could cause injury if the airbag is
triggered.ModificationsModifications must always be carried out according to
our specifications.Unauthorised modifications to the electronic components or soft-
ware in the vehicle may cause malfunctioning. Due to the way the
electronic components are linked together in networks, other
systems may be affected by the faults. This can seriously impair
safety, lead to excessive wear of components, and also invalidate
the type approval for your vehicle.
You will appreciate that your Audi dealer cannot be held liable for
any damage caused by modifications and/or work performed incor-
We recommend that all work should be performed by an Audi work-
shop using Audi Genuine parts
Incorrectly performed modifications or other work on your vehicle
can lead to malfunctions and cause accidents.
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Accessories and modifications to the vehicle 278Radio transmitters and business equipmentRadio transmitters (fixed installation)
Retrofit installations of radio transmitters in the vehicle are subject
to official approval. Audi generally authorises in-vehicle installa-
tions of approved types of radio transmitters provided that:•
the aerial is installed correctly,
the aerial is not installed in the interior of the vehicle (and
screened cables are used together with non-reflective aerial trim-
the effective transmitting power does not exceed 10 Watts at the
Audi dealers and specialist retailers will be able to inform you about
options for installing and operating radio transmitters with a higher
Mobile radio transmitters
When using commercial mobile telephones or radio equipment it is
possible that they might interfere with the electronics of your
vehicle and cause malfunctions. The reasons could be:
no external aerial
external aerial incorrectly installed
transmitting power more than 10 W.
Therefore you must not operate portable mobile telephones or radio
equipment inside the vehicle without a correctly installed external
Please note also that the maximum range of the equipment can only
be achieved with an external aerial.
Retrofit installation of business or other equipment in the vehicle is
permitted, provided the equipment cannot interfere with the driver's immediate control of the vehicle. Any such equipment must
carry the CE mark. Any retrofit equipment that could influence the
driver's control of the vehicle must have a type approval for your
vehicle and must carry the e mark.
Mobile telephones or radio equipment which are operated inside
the vehicle without a correctly installed external aerial can create
excessive magnetic fields that could cause a health hazard.
Any retrofit installation of electrical or electronic equipment in
the vehicle will affect its type approval. In extreme cases this could
mean that you might lose the type approval for your vehicle.
Please refer to the mobile telephone/radio operating
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