Volvo 2009 S60 - Manual (Page 155)

07 Wheels and tires
General information
07
155
Tread wear indicator
G020323
Tread wear indicator
The tires have wear indicator strips running
across or parallel to the tread. The letters TWI
are printed on the side of the tire. When
approximately 1/16 " (1.6 mm) is left on the
tread, these strips become visible and indicate
that the tire should be replaced. Tires with less
than 1/16 " (1.6 mm) tread offer very poor trac-
tion.
When replacing worn tires, it is recommended
that the tire be identical in type (radial) and size
as the one being replaced. Using a tire of the
same make (manufacturer) will prevent altera-
tion of the driving characteristics of the vehicle.
New tires
Remember that tires are per-
ishable goods. As of 2000, the
manufacturing week and year
will be indicated with 4 digits
(e.g. 1502 means that the tire
illustrated was manufactured
during week 15 of 2002).
Tire age
Tires degrade over time, even when they are
not being used. It is recommended that tires
generally be replaced after 6 years of normal
service. Heat caused by hot climates, frequent
high loading conditions or Ultra Violet (U.V)
exposure can accelerate the aging process.
You should replace the spare tire when you
replace the other road tires due to the aging of
the spare.
A tire's age can be determined by the DOT
stamp on the sidewall (see the illustration
above).
A tire with e.g., visible cracks or discoloration
should be replaced immediately.
Improving tire economy:
• Maintain correct tire pressure. See the tire
pressure tables on pages 158 and 159.
• Drive smoothly: avoid fast starts, hard
braking and tire screeching.
• Tire wear increases with speed.
• Correct front wheel alignment is very
important.
• Unbalanced wheels impair tire economy
and driving comfort.
• Tires must maintain the same direction of
rotation throughout their lifetime.
When replacing tires, the tires with the most
tread should be mounted on the rear wheels to
reduce the chance of oversteer during hard
braking.
Hitting curbs or potholes can damage the tires
and/or wheels permanently.