The tires should be rotated as specified in the Maintenance Intervals Chart. Refer to the accompanying illustrations for the recommended rotation patterns.
The tires on your truck should have built-in tread wear indicators, which appear as 1 / 2 inch (12.7mm) bands when the tread depth gets as low as 1 / 16 inch (1.6mm). When the indicators appear in 2 or more adjacent grooves, it's time for new tires.
For optimum tire life, you should keep the tires properly inflated, rotate them often and have the wheel alignment checked periodically.
Some late models have the maximum load pressures listed in the V.I.N. plate on the left door frame. In general, pressure of 28-32 psi would be suitable for highway use with moderate loads and passenger truck type tires (load range B, non-flotation) of original equipment size. Pressures should be checked before driving, since pressure can increase as much as 6 psi due to heat. It is a good idea to have an accurate gauge and to check pressures weekly. Not all gauges on service station air pumps are to be trusted. In general, truck type tires require higher pressures and flotation type tires, lower pressures.
See Figures 1 and 2
It is recommended that you have the tires rotated every 6,000 miles. There is no way to give a tire rotation diagram for every combination of tires and vehicles, but the accompanying diagrams are a general rule to follow. Radial tires should not be cross-switched; they last longer if their direction of rotation is not changed. Truck tires sometimes have directional tread, indicated by arrows on the sidewalls; the arrow shows the direction of rotation. They will wear very rapidly if reversed. Studded snow tires will lose their studs if their direction of rotation is reversed.
Mark the wheel position or direction of rotation on radial tires or studded snow tires before removing them.
If your truck is equipped with tires having different load ratings on the front and the rear, the tires should not be rotated front to rear. Rotating these tires could affect tire life (the tires with the lower rating will wear faster, and could become overloaded), and upset the handling of the truck.
See Figures 3, 4 and 5
The tires on your truck were selected to provide the best all around performance for normal operation when inflated as specified. Oversize tires (Load Range D) will not increase the maximum carrying capacity of the vehicle, although they will provide an extra margin of tread life. Be sure to check overall height before using larger size tires which may cause interference with suspension components or wheel wells. When replacing conventional tire sizes with other tire size designations, be sure to check the manufacturer's recommendations. Interchangeability is not always possible because of differences in load ratings, tire dimensions, wheel well clearances, and rim size. Also due to differences in handling characteristics, 70 Series and 60 Series tires should be used only in pairs on the same axle; radial tires should be used only in sets of four.
The wheels must be the correct width for the tire. Tire dealers have charts of tire and rim compatibility. A mismatch can cause sloppy handling and rapid tread wear. The old rule of thumb is that the tread width should match the rim width (inside bead to inside bead) within an inch. For radial tires, the rim width should be 80% or less of the tire (not tread) width.
The height (mounted diameter) of the new tires can greatly change speedometer accuracy, engine speed at a given road speed, fuel mileage, acceleration, and ground clearance. Tire manufacturers furnish full measurement specifications. Speedometer drive gears are available for correction.
Dimensions of tires marked the same size may vary significantly, even among tires from the same manufacturer.
The spare tire should be usable, at least for low speed operation, with the new tires.
See Figure 6
For maximum satisfaction, tires should be used in sets of five. Mixing or different types (radial, bias ply, fiberglass belted) should be avoided. 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 tread and sidewall. 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 the radial tire. Tread life is improved considerably over the conventional bias tire. The radial tire differs in construction; instead of the carcass plies running at an angle of 90° to each other, they run at an angle of 90° to the bead. This gives the tread a great deal of rigidity and the sidewall a great deal of flexibility and accounts for the characteristic bulge associated with radial tires.
Radial tire are recommended for use on all Ford trucks. If they are used, tire sizes and wheel diameters should be selected to maintain ground clearance and tire load capacity equivalent to the minimum specified tire. Radial tires should always be used in sets of five, but in an emergency radial tires can be used with caution on the rear axle only. If this is done, both tires on the rear should be of radial design.
Radial tires should never be used on only the front axle.
Store the spare tire AND ALL ACCESSORIES in their proper places . Leaving them out invites damage and noise.
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.
CARE FOR ALUMINUM WHEELS
Aluminum wheels should be cleaned and waxed regularly with products developed specifically for aluminum products. Read the label of any product you are considering using prior to application. Do not use abrasive cleaners because they may damage the protective coating.