Файл: 92FWD_22.pdf

GENERAL INFORMATION

Original equipment wheels are designed for proper operation at all loads up to the maximum vehicle capacity.

All models use steel or cast aluminum drop center wheels. The safety rim wheel (Fig. 1) has raised sections between the rim flanges and the rim well A.

sively tightening them in sequence (Fig. 2). Tighten wheel nuts to 129 NIm (95 ft. lbs.). Never use oil or grease on studs or nuts.

Fig. 1 Safety Rim

Initial inflation of the tires forces the bead over these raised sections. In case of tire failure the raised sections help hold the tire in position on the wheel until the vehicle can be brought to a safe stop.

Cast aluminum wheels require special balance weights and alignment equipment.

WHEEL INSTALLATION

The wheel studs and nuts are designed for specific applications and must be replaced with equivalent parts. Do not use replacement parts of lessor quality or a substitute design. All aluminum and some steel wheels have wheel stud nuts which feature an enlarged nose. This enlarged nose is necessary to ensure proper retention of the aluminum wheels.

Before installing the wheel, be sure to remove any build up of corrosion on the wheel mounting surfaces with scraping and wire brushing. Installing wheels without good metal-to-metal contact could cause later loosening of wheel nuts. This could adversely affect the safety and handling of your vehicle.

To install the wheel, position it properly on the mounting surface using the hub pilot as a guide. All wheel nuts should be lightly tightened before progres-

Fig. 2 Tightening Wheel Nuts (5-Stud)

WHEEL REPLACEMENT

Wheels must be replaced if they:

²have excessive run out

²are bent or dented

²leak air through welds

²have damaged bolt holes

Wheel repairs employing hammering, heating, or welding are not allowed.

Original equipment replacement wheels are available through your dealer. When obtaining wheels from any other source, the replacement wheels should be equivalent in load carrying capacity. The wheel dimensions (diameter, width, offset, and mounting configuration) must match original equipment wheels. Failure to use equivalent replacement wheels may adversely affect the safety and handling of your vehicle. Replacement with used wheels is not recommended as their service history may have included severe treatment or very high mileage and they could fail without warning.

TIRE AND WHEEL BALANCE

Balancing need is indicated by vibration of seats, floor pan, or steering wheel when driving over 90 km/h (55 mph) on a smooth road.

It is recommended that a two plane dynamic balancing machine be used when a wheel and tire assembly require balancing. Static balancing should be used only when a two plane dynamic balancing is not available.

For static imbalance, find location of heavy spot causing imbalance and counterbalance wheel directly opposite the heavy spot. Determine weight required to counterbalance the area of imbalance. Place half of this weight on the inner rim flange. Then place the other half on the outer rim flange (Fig. 3). Off-vehicle balancing is preferred.

Fig. 3 Counterbalancing

TIRE AND WHEEL RUN OUT

Radial run out is the difference between the high and low points on the tire or wheel periphery.

Lateral run out is the wobble of the tire or wheel. Radial run out of more than 1.5 mm (.060 inch) measured at the center line of the tread may cause

the vehicle to shake.

Lateral run out of more than 2.0 mm (.080 inch) measured near the shoulder of the tire may cause the vehicle to shake.

Sometimes radial run out can be reduced by relocating the wheel and tire assembly on the mounting studs (See Method 1). If this does not reduce run out to an acceptable level, the tire can be rotated on the wheel. (See Method 2).

METHOD 1 (RELOCATE WHEEL ON HUB)

Check accuracy of the wheel mounting surface;adjust wheel bearings.

Drive vehicle a short distance to eliminate tire flat spotting from a parked position.

Make sure all wheel nuts are properly torqued (Fig. 2).

Use run out gauge D-128-TR to determine run out (Fig. 4).

Fig. 4 Run out Gauge D-128-TR

Relocate wheel on the mounting, two studs over from the original position.

Retighten wheel nuts (Fig. 2) until all are properly torqued, to eliminate brake distortion.

Check radial run out. If still excessive, mark tire sidewall, wheel, and stud at point of maximum run out (Fig. 5), and proceed to Method #2.

Fig. 5 Chalk Marking on Wheel, Tire, and Stud

METHOD 2 (RELOCATE TIRE ON WHEEL)

Rotating tire on wheel is particularly effective when there is run out in both tire and wheel.

Remove tire from wheel and remount wheel on hub in former position.

Check wheel radial run out (Fig. 6). It should be no more than 0.9 mm (.035 inch).