See Figure 1
To equalize tire wear and increase the mileage you obtain from your tires, rotate them every 7,500 miles (12,000 km). All Volkswagens are designed for radial tires. Radial tires should be rotated by moving the front tires to the rear and the rear tires to the front. You can rotate them diagonally, however, this should not be done unless the tire is exhibiting unusual wear such as feather-edging. Do not rotate studded snow tires or directional tires diagonally.
When buying new tires, they should always be replaced in sets of two or four. Always install the same type of tire on all four wheels. Mixing of different types (radial, bias-belted, fiberglass belted) or tread patterns can be hazardous because vehicle handling becomes inconsistent.
Conventional bias tires are constructed so that the cords run bead to bead at an angle. Alternate plies run at an opposite angle. This type of construction gives rigidity to both the tread and the side wall and is good for carrying heavy loads.
Bias belted tires are similar in construction to conventional bias ply tires. Belts run at an angle and also at a 90° angle to the bead, as in radial tires. Tread life is improved considerably over the conventional bias tire and the side wall remains fairly rigid.
On radial tires, instead of the cords and belts being at an angle of 90° to each other, they are all parallel and at an angle of 90° to the bead. The cords wrap directly across the carcass of the tire to make the shortest line from bead to bead. This gives the tread a great deal of rigidity and the side wall a great deal of flexibility. With this construction, it is easier for the tread to stay flat on the road when the vehicle is turning and tire side loads are high. These tires also tend to be rounder and have less rolling resistance. Dry and wet road handling are greatly improved over bias or belted tires. This type of construction accounts for the characteristic bulge associated with radial tires because the side walls are relatively unsupported. This makes proper inflation pressure important to tire life and performance.
Store the tires at the proper inflation pressure if they are mounted on wheels. Keep them in a cool dry place, laid on their sides. If the tires are stored in the garage or basement, do not let them stand on a concrete floor. Set them on strips of wood.
See Figure 2
Tire inflation is the most ignored item of auto maintenance, and one of the most important. Buy a tire pressure gauge and keep it in the glovebox of your vehicle. Service station air gauges are generally either not working or inaccurate and should not be relied upon. Also, using the same gauge all the time increases the accuracy of your pressure readings. The tire pressures recommended for your car are usually found on the left door post and in the owner's manual. Never exceed the maximum pressure shown on the tire sidewall. Always check tire pressure when the tires are cool because air pressure increases with heat. Readings can change as much as 4-6 psi depending on tire temperature. For every 10° rise (or drop) in tire temperature, there is a difference of 1 psi. This explains why tires loose pressure when the weather turns colder.
Excess heat generated while driving on an underinflated tire causes serious damage to the structure of the tire. For long highway drives, inflating the tires to within 3-4 psi (cold pressure) of the maximum allowed will increase fuel mileage and tire life.
See Figures 3, 4 and 5
Tires have 7 built-in tread wear indicator bars that show up as 1 / 2 inch (13mm) wide smooth bands across the tire when 1 / 16 inch (1.5mm) 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 this amount of 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 2 adjacent grooves, the tires have less than 1 / 16 inch (1.5mm) tread left and should be replaced. You can measure snow tires in the same manner by using the tail side of the Lincoln penny. If you can see the top of the Lincoln memorial, it's time to replace the snow tires.
CARE OF SPECIAL WHEELS
If you have invested money in magnesium, aluminum alloy or sport wheels, special precautions should be taken to make sure your investment is not wasted and that your special wheels look good for the lifetime of the vehicle.
Special wheels are easily scratched and/or damaged. Occasionally check the rims for cracking, impact damage or air leaks. If any of these are found, replace the wheel. In order to prevent this type of damage, and the costly replacement of a special wheel, observe the following precautions: