To equalize tire wear and increase the mileage you obtain from your tires, rotate them every 7500 miles. All Audi A4 and VW Passat models are designed to use radial tires. Radial tires should be rotated by moving the front tires to the rear and the rear tires to the front. Do NOT move them from side to side unless absolutely necessary, or unless the tire is near the end of its life anyway. Radial tires tend to distort slightly and take a set in the direction of rotation. If a tire is moved from one side to the other and turns the opposite direction, the ride and handling will be affected and the tire may wear faster.
On Quattro models (all wheel drive), frequent tire rotation will prolong the life of the tires.
Always tighten and torque the lug bolts evenly using a crisscross pattern.
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) 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 sidewall 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 sidewall 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 sidewall a great deal of flexibility. With this construction, it is easier for the tread to stay flat on the road when the car 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 is greatly improved over bias or belted tires. This type of construction accounts for the characteristic bulge associated with radial tires because the sidewalls are relatively unsupported. This makes proper inflation pressure so important to tire life and performance.Tire Storage
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.INFLATION PRESSURE
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 car. 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. If you are driving on replacement tires of a different type, follow the inflation recommendations of the tire manufacturer.
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 under inflated 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.TREAD DEPTH
All tires have 7 built-in tread wear indicator bars that show up as 13mm (1/2 inch) wide smooth bands across the tire when 1.5mm (1/16 inch) 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 1.5mm (1/16 inch) 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 1.5mm (1/16 inch) tread left and should be replaced. You can measure snow tires in the same manner by using the tails side of the Lincoln penny. If you can see the top of the Lincoln memorial, it's time to replace the snow tires.