Common sense and good driving habits will afford maximum tire life. Fast starts and stops, and hard cornering are hard on tires and will shorten their useful life span. If you start at normal speeds, allow yourself sufficient time to stop, and take corners at a reasonable speed, the life of your tires will increase greatly. Also make sure that you don't overload your vehicle or run with incorrect pressure in the tires. Both of these practices increase tread wear.
Inspect your tires frequently. Be especially careful to watch for bubbles in the tread or side wall, deep cuts, or underinflation. Replace any tires with bubbles. If the cuts are so deep that they penetrate to the cords, discard the tire. Any cut in the sidewall of a radial tire renders it unsafe. Also look for uneven tread wear patterns that indicate that the front end is out of alignment or that the tires are out of balance.
See Figure 1
Conventional bias ply tires are constructed so that the cords run bead-to-bead at an angle. This type of construction gives rigidity to both tread and sidewall.
Bias-belted tires are an evolutionary improvement over bias ply tires. Belts are laid at alternating angles from bead-to-bead, and also at a 90° angle to the bead, as in the radial tire. Tread life is improved considerably over the conventional bias ply tire.
The radial tire differs in construction. Instead of the carcass plies running at an angle of 90° to each other, they run at a 90° angle to the bead. This gives the tread and sidewall a great deal of flexibility and accounts for the characteristic bulge surrounding the contact patch associated with radial tires.
Snow tires should not be operated at sustained speeds over 70 mph (113 kph), unless they are specially designed as "performance snow tires" and carry a manufacturer's speed rating.
When buying new tires, you should keep the following points in mind, especially if you are switching to larger tires or a different profile series (for example: 50, 60, 65, 70, 78):
See Figure 2
Tire inflation is generally the most ignored item of auto maintenance, a potentially costly and hazardous oversight. When underinflated, tires wear unevenly requiring early replacement. Also the contact patch of a poorly inflated tire is less stable and therefore provides less grip. An underinflated tire is more prone to bottoming-out over bumps and potholes leading to bent wheels, flats, or both. Increased load (such as when carrying passengers, cargo or both) will exacerbate any of the above problems. Studies have shown gasoline mileage can drop as much as 0.8% for every 1 psi (7 kPa) of underinflation.
Two items should be a permanent fixture in every glove compartment: a tire pressure gauge and a tread depth gauge. Check the tire pressure, including the spare, regularly with a pocket type gauge or preferably, a dial gauge. Kicking the tires won't tell you a thing, and the gauge on a service station air hose is notoriously inaccurate.
Avoid dropping a dial gauge or exposing it to sudden shocks, as this may cause it to go out of calibration.
A plate located on the left door will tell the proper pressure for the tires. Ideally, inflation pressure should be checked before driving when the tires are cold. When driven on, tires flex, create friction, and the air inside them expands increasing pressure.) Every 10°F (5.6°C) rise or drop in temperature means a difference of 1 psi (7 kPa), which explains why the tire seems to lose air on a cold night or during the fall and winter seasons. When it is impossible to check the tires cold, allow for pressure build-up due to heat. If the hot pressure exceeds the cold pressure by more than 15 psi (104 kPa), reduce vehicle speed, load or both. This is a sure sign that excess internal heat is being created in the tire, and the temperature could continue to rise. If the heat approaches the temperature at which the tire was cured during manufacture, the tread could separate from the body.
Before starting a long trip with lots of luggage, you can add about 2-4 psi (14-28 kPa) to the tires to make them run cooler but never exceed the maximum inflation pressure on the side of the tire.
See Figures 3, 4 and 5
All tires made since 1968 have eight built-in tread wear indicator bars. They show up as 1 / 2 in. (13mm) wide smooth bands across the tire when 1 / 16 in. (1.6mm) of tread remains. The appearance of tread wear indicators means that the tires should be replaced. In fact, many states have laws prohibiting the use of tires with less than 1 / 16 in. (1.6mm) tread.
You can check your own tread depth with an inexpensive gauge or by using a Lincoln head penny. Slip the Lincoln penny into several tread grooves. If you can see the top of Lincoln's head in two adjacent grooves, the tires have less than 1 / 16 in. (1.6mm) tread left and should be replaced. You can measure snow tires in the same manner by using the "tails" side of the Lincoln penny.
A tread depth gauge will allow you to more accurately monitor the wear of your tires over time and you will be able to check that the tire is wearing evenly across the tread width.
See Figure 6
If studded snow tires are used, be sure to mark the wheel position or direction of rotation before removal, since such tires are unidirectional.
So that the tires wear more uniformly, it is recommended that the tires be rotated every 6000 miles (9662 km). This can be done when all four tires are of the same size and load rating capacity. Any abnormal wear should be investigated and the cause corrected.
Store the tires at proper inflation pressure if they are mounted on wheels. All tires should be kept in a cool, dry place. If they are stored in the garage or basement, do not let them stand on a concrete floor, set them on strips of wood.
ALLOY WHEEL CARE
See Figure 7
Some Volvos are equipped with aluminum alloy wheels. These wheels are protected with a clear-coat finish when they are manufactured. This finish protects the alloy wheel from tarnishing or discoloring. When these wheels are handled, care should be taken to not scratch the coating. Also, when having replacement tires mounted, be sure to first inquire that the shop doing the work is equipped with a tire changing machine designed to not scratch alloy wheels. Traditional steel wheel tire changers may gouge the finish of alloy wheels.
Alloy wheels should be cleaned periodically (as-needed) to prevent potentially harmful road dirt and chemical buildup from eating away at the clear-coat finish. When cleaning alloy wheels, use only non-acid-based and non-abrasive cleaners. Cleaners containing harsh acids will etch the wheel surface and cause the coating to peel off. There are many good quality cleaners available that are specifically designed to cut the grime from alloy wheels without attacking the finish (soap and water will work, but brake dust stuck to the wheels is hard to remove). Always follow the manufacturer's directions given on the container when using a specific cleaner.