Contents: Examination ↳ Checking the radial and lateral… ↳ Elimination of radial runout ↳ Checking the radial and lateral… ↳ Mounting wheels on a car ↳ Subsequent equilibration or… ↳
Vibration of the steering wheel at a certain speed usually indicates an imbalance of the wheels.
Examination
Check the tire pressure and adjust if necessary.
Perform a test drive. Determine as accurately as possible the limits of the malfunction manifestation - the speed range, road conditions, driving on turns and in a straight line.
Raise the car onto the trestles.
Check the centering of the middle part of the rim. The wheel hub or brake drum should protrude above the console of the disc wheel or at least end with it. Otherwise, replace the rim.
Check the wheel suspensions. To do this, check the rubber-metal bearings, joints, shock absorbers and rims for perfect condition.
Remove the wheels and clean them. Also remove any stones from the tread.
Check the tires for wear spots. These are areas with a slight tread depth that can occur as a result of the wheel locking up when braking.
Check the tread depth of individual tires and compare them with each other. If the tires are abnormally worn at the front and/or rear, it is necessary to determine the parameters of the vehicle's chassis at the front and rear and adjust them if necessary. In this case, the wheel alignment must be adjusted to the upper tolerance limit.
Attention: To determine the parameters of the chassis, appropriate measuring equipment is required, which, as a rule, is only available at service stations.
Perform a test drive and check if there are any other faults.
Checking the radial and lateral runout of wheels
With the vehicle raised, place the linear movement indicator first on the tread track and then on the sidewall of the tire. Slowly turn the wheel by hand and read the readings from the indicator scale. Mark the maximum radial runout on the tire with chalk.
Prescribed wheel runout values: maximum radial runout is 2.0 mm, maximum lateral runout is 2.0 mm.
If these values are not maintained, balance the wheels on a stationary balancing machine. In this case, the wheels, as on a car, must be centered in the middle part. Conical clamping devices that center the wheel relative to the central hole are not allowed. The permissible residual imbalance in both balancing planes is 5 grams.
Elimination of radial runout
Release the air from the tire and press the tire bead against the base of the rim.
Rotate the tire on the rim by 120°.
Inflate the tire and check the radial runout again.
If the measured value exceeds the specified value, rotate the tyre on the rim another 120° and check the radial runout.
If the prescribed maximum value is observed, perform wheel balancing.
Checking the radial and lateral runout of the rim
Center the rim without the tire in the middle part on the balancing machine or install it on the hub of the car wheel. Install the linear displacement indicator.
Perform measurements of radial and lateral runout of the rim. Radial runout (non-cylindrical) is measured on the rim shoulder, and lateral runout - on the side surface of its flange. In this case, local deviations in the readings of the dial indicator caused by elevations or depressions in the rim material are not taken into account.
Prescribed runout values for steel rim: maximum radial runout is 2.0 mm; maximum lateral runout - 2.0 mm.
Prescribed runout values for light alloy rims: maximum radial runout is 0.5 mm; maximum lateral runout - 0.8 mm.
If the measured runout values exceed the specified values, replace the rim.
Mounting wheels on a car
With the vehicle raised on trestles, position the wheels so that the maximum radial runout is at the top. In this position, tighten the wheel nuts crosswise with a torque wrench to 100 Nm.
Note: If the difference in wear between individual tires is insignificant, install the wheels with the smallest radial runout and minimum imbalance on the front axle.
Perform a test drive. If vibrations still occur at the front of the vehicle or at the steering wheel, this may be due to residual imbalance, which can be corrected by subsequent balancing on the vehicle.
Subsequent equilibration or balancing of wheels on a car
When balancing the drive wheels, it is necessary to rotate both tires of one axle.
The wheels must be driven by the car's engine so that the wheels rotate synchronously.
Take a test drive.
If the faults still occur, the radial or lateral runout of one or more tires is too large. This cannot be measured with workshop instruments. In this case, the only option is to replace the front and/or rear tires. In this case, the tires must be replaced in pairs, i.e. for the entire axle at the same time.
The material was copied from an information website [FordBook.ru]