Volvo XC90 Owner's Manual page 187

age and decompose, even if they are hardly
ever or never used. The function can there-
fore be affected due to the tyre's constituent
materials being broken down. In such a case
the tyre should then not be used.This also
applies to spare tyres, winter tyres and tyres
saved for future use. Examples of external
signs which indicate that the tyre is unsuita-
ble for use are cracks or discoloration.
The age of the tyre can be determined by the
DOT marking, see illustration above.
More even wear and maintenance
The correct tyre pressure results in more even
wear, see page 298. Driving style, tyre pres-
sure, climate and road condition affect how
quickly your tyres age and wear. To avoid dif-
ferences in tread depth and to prevent wear
patterns arising, the front and rear wheels can
be switched with each other. A suitable dis-
tance for the first change is approx. 5000 km
and then at 10 000 km intervals. Volvo rec-
ommends that you contact an authorised
Volvo workshop for checking if you are uncer-
tain about tread depth. If significant differen-
ces in wear (>1 mm difference in tread depth)
between tyres have already occurred, the
least worn tyres must always be placed on
the rear. Understeer is normally easier to cor-
rect than oversteer, and leads to the car con-
tinuing forwards in a straight line rather than
having the rear end skidding to one side,
resulting in possible complete loss of control
over the car. This is why it is important for the
rear wheels never to lose grip before the front
wheels.
Wheels should be stored lying down or hang-
ing up, and not standing up.
Tyres with tread wear indicators
Tread wear indicators.
Tread wear indicators are narrow treadless
bands across the width of the tread. On the
side of the tyre are the letters TWI (Tread
Wear Indicator). When the tyre's tread depth
is down to 1.6 mm, the tread depth will be
level in height with the tread wear indicators.
07 Wheels and tyres
Change to new tyres as soon as possible.
Remember that tyres with little tread depth
provide very poor grip in rain and snow.
Winter tyres
Volvo recommends winter tyres with specific
winter tyre dimensions. Tyre dimensions are
dependent on engine variant. When driving
on winter tyres, they must be fitted to all four
wheels.
NOTE
Ask a Volvo dealer which rim and tyre
types are most suitable.
Studded tyres
Studded winter tyres should be run in gently
for 500 – 1000 km so the studs settle properly
into the tyre. This gives the tyre, and espe-
cially the studs, a longer service life.
NOTE
The legal provisions for the use of studded
tyres vary from country to country.
Tread depth
Road conditions with ice, slush and low tem-
peratures place considerably higher demands
on tyres than summer conditions. It is there-
fore recommended not to drive on winter
General
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