248 Tires and wheels
driving a few yards and correct if neces
sary. Follow the instructions from the
snow cha in manufacturer when doing so.
(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 rims. 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
securely 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 model
¢ page 275.
.&_ WARNING
Improperly tightened or maintained wheel
bolts can become loose causing loss of
control, a collision and serious persona l in
Jury.
- Always keep the wheel bolts and the
threads in the wheel hubs clean so the
wheel bolts can turn easily and be prop
erly tightened.
- Never grease or oil the wheel bolts and
the threads in the wheel hubs. They can
become loose while driving if greased or
oiled, even if tightened to the specified
torque.
- Only use wheel bolts that belong to the
rim being installed.
- Never use different wheels bolts on your
vehicle.
- Always maintain the correct tightening
torque for the wheel bolts to reduce the
risk of a wheel loss . If the tightening tor
que of the wheel bolts is too low, they
can loosen and come out when the veh i- cle
is moving.
If the tightening torque is
too high, the wheel bolts and threads
can be damaged and the wheel can be
come loose.
(D Note
The specified torque for the whee l bolts is
90 ft lbs . (120 Nm) with a tolerance of
± 7,4 ft lbs. (± 10 Nm). Torque wheel bolts
diagonally . After changing a wheel, the
torque must be checked as soon as possi
ble with a torque wrench -preferably by an
authorized Audi dealer or qualified work
shop.
Low aspect ratio tires
Your Audi is factory -equipped with low aspect
ratio tires. These tires have been thoroughly
tested and been se lected specifically for your
model for their superb performance, road feel
and handling under a variety of driving condi
t ions . Ask your authorized Audi dealer for
more details .
The low aspect ratio of these tires is indicated
by a numeral of
55 or less in the tire's s ize
designation . The numeral represents the ratio
of the tire's sidewall height in relation to its
tread width expressed in percentage. Conven
tional tires have a height/w idth rat io of 60 or
more.
The performance of low-aspect-ratio tires is
particularly sensitive to improper inflation
pressure. It is therefore important that low
aspect ratio tires are inflated to the specified
pressure and that the inflation pressure is
regularly checked and maintained. Tire pres
sures should be checked at least once a
month and always before a long trip
¢ page 237, Checking tire pressure.
What you can do to avoid tire and rim
damage
Low aspect ratio tires can be damaged more
easily by impact with potholes, curbs, gul lies
or ridges on the road, particularly if the tire is
underinflated . ..,.
