07 Wheels And Tyres; General - Volvo C30 Owner's Manual

07 Wheels and tyres

General

Driving characteristics and tyres
The tyres greatly affect the car's driving cha-
racteristics. The type of tyre, dimensions, tyre
pressure and speed rating are important for
how the car performs.
When changing tyres, ensure that tyres of the
same type and dimensions, and preferably also
the same make, are fitted to all four wheels.
Follow the recommended tyre pressures
specified on the tyre pressure label, see
page 190.
Designation of dimensions
The dimensions are stated on all car tyres.
Example: 205/55R16 91 W.
205 Tyre width (mm)
55 Ratio between tyre wall height and
tyre width (%)
R Radial ply
16 Rim diameter in inches (")
07
91 Tyre load index (in this case 615 kg)
W Speed rating for maximum permitted
speed (in this case 270 km/h).
186
Speed ratings
The car is approved as a whole, which means
that dimensions and speed ratings must not
differ from those specified on the vehicle reg-
istration document. The only exception to
these conditions is winter tyres (both those
with metal studs and those without). If such a
tyre is chosen, the car must not be driven faster
than the speed rating of the tyre (for example,
class Q can be driven at a maximum of
160 km/h).
Remember that traffic regulations determine
how fast a car can be driven, not the speed
class of the tyres.
Note! Maximum permitted speeds indicated.
Q 160 km/h (used only on winter tyres)
T 190 km/h
H 210 km/h
V 240 km/h
W 270 km/h
Y 300 km/h
New tyres
Tyres are perishable. After a few years they
begin to harden at the same time as the friction
capacity/characteristics gradually deteriorate.
For this reason, aim to get as fresh tyres as
possible when you replace them. This is espe-
cially important with regard to winter tyres. The
last four digits in the sequence mean the week
and year of manufacture. This is the tyre's
DOT marking (Department of Transportation),
and this is stated with four digits, for example
1510. The tyre in the illustration was manufac-
tured in week 15 of 2010.
Tyre age
All tyres older than six years should be checked
by an expert even if they seem undamaged.