Volvo 780 Owner's Manual page 65

1989 Volvo 780
periods can cause wheel and/or tire damage.
pg. 61 Wheels and tires
Wear indicator
The tires have a so-called "wear indicator" in the form of a number of narrow strips running across or
parallel to the tread. When approx. 1/16"(1.5 mm) is left on the tread, these strips show up and indicate
that the tire should be replaced.
Tires with less than 1/16" (1.5 mm) tread have a very poor grip in rain or snow.
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 alteration of the driving
characteristics of the vehicle.
To improve tire economy:
Maintain correct tire pressure.
Drive smoothly: avoid fast starts, hard braking and tire screeching.
Tire wear increases with speed.
Do not change wheel location unless necessary.
Correct front wheel alignment is very important.
Unbalanced wheels impair tire economy and driving comfort.
Hitting curbs can damage the tires and/or wheels permanently.
Flat spots
All tires become warm during use. After cooling, when the vehicle is parked, the tires have a tendency to
distort slightly, forming flat spots. These flat spots can cause vibrations similar to the vibrations caused
by balanced wheels.
They do, however, disappear when the tire warms up. The degree to which flat spots form depends on
the type of cord used in the tire. Remember that, in cold weather, it takes longer for the tire to warm up
And consequently longer for the flat spot to disappear.
Snow tires, studded tires, snow chains
Tires for winter use:
Use snow tires fitted to the standard 15" wheel rims. Suitable tire sizes: 185/65R15 or 175/70R15 on all
four wheels.
Do not mix tires of different design, as this could negatively affect overall tire road grip especially
during slippery road conditions!
Studded tires should be run-in 300-600 miles (500-1000 km) during which the car should be driven as
smoothly as possible to give the studs the opportunity to seat properly in the tires. The car tires should
have the same rotational direction throughout their entire lifetime. In other words, if you wish to rotate
the wheels, make sure that the same wheels are always on the same side of the car.
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