Vauxhall VECTRA Owner's Manual page 224

Tread dept h
Check tread depth regularly. If the front
tyres show greater wear than the rear
tyres, swa p the front wheels with the rea r
wheels so that the tyres with deep er tread
are on the front axle.
For reasons of safety, tyres should be
rep la ced when their tread depth has worn
down to 2 to 3 mm (winter tyres: 4 mm).
222
The leg ally permissible minimum trea d
depth (1.6 mm) has been reached when
the tread has worn down as far as one of
1 )
the wear indicators (TWI ). A number of
wear indicators are sp aced at eq ual
intervals around the tyre within the trea d.
Their position is indicated by m arkings on
the tyre sid ewall.
General i nformati on
z The danger of aq uap laning is greater if
the ty res are worn.
z Tyres age, even if they a re used only very
little or not at all. A spare wheel which
has not b een used for six years should be
used only in emergencies; drive slowly
when using suc h ty res.
1) TWI T W I
= rea d ear n dica to r.
z Never fit used tyres the previous history
and use of which you do not k now.
z So as not to impair b ra ke cooling, use
only wheel trims approved for use on
your vehicle.
Tyre d esigna tions
Meaning s:
e.g. 195/65 R 15 91 H
195 = Tyre width in mm
65 = Aspect ratio
(ty re height to tyre width) in %
R = Belt ty pe: Radial
15 = Rim diam eter in inches
91 = Load ind ex
e.g .: 91 represents 618 kg
H = Speed cod e
S peed code letters:
Q Up to 100 mph (160 km /h)
S Up to 112 mph (180 km /h)
T Up to 118 mph (190 km /h)
H Up to 130 mph (210 km /h)
V Up to 150 mph (240 km /h)
W Up to 168 mph (270 km /h)