2. Wheel Imbalance
Reasons:
• A new tyre may look perfectly round and balanced, but there are
small variations in weight around its circumference. Tyres also
have slight weight imbalances, whether from a joining point of the
plies or a slight deviation from perfectly round.
• Wheel rims also contribute to imbalances. The wheel's valve stem
hole reduces a small amount of weight from that side of the
wheel.
• Even if the wheel was perfectly balanced, weight distribution
around its circumference becomes uneven with wear. This change
in weight causes the wheels to become unbalanced.
3. • At high speeds, a small imbalance in weight becomes a large
imbalance in centrifugal force, causing the wheel/tyre assembly
to rotate with stomping motion. This results in vibration in the car
as well as some very irregular and damaging wear on the tyres.
• Hitting a pothole or a curb with tyre or rim makes a previously
balanced wheel unbalanced.
• Wheel impacts and the normal stresses of driving may cause a
wheel balancing weight to become dislodged. In such a case,
immediate onset of vibration will be experienced
Symptoms:
• Vibration/wobble in the steering wheel at certain highway
speeds.
• Vibration in the seat or floorboard at certain highway speeds.
• Wear pattern on the tyres
Wheel Imbalance
4. Effects
• Accelerated and uneven tyre wear.
• Undue load on suspension.
• Damage to steering components.
• Driver fatigue
• Reduced traction and steering control
• Increased fuel consumption
Wheel Imbalance
5. • Mark the wheels in relation to their location on the vehicle
and then remove them. This eliminates chance of mixing
up the wheel’s position to the hub when replacing it.
• Check and adjust the tyre pressure before balancing the
wheel
• Remove any old weights from the wheel and clean it
thoroughly. Make sure the valve stem cap is installed
• Mount the wheel and tyre on the balancer, putting the
inside part of the tyre on first. Secure the wheel with the
hub nut assembly.
• Determine balancing settings
Wheel Balancing Procedure
6. • Turn the balancer on to rotate the wheel. Read the
balancing machine analysis, which tells whether the
wheel is out of balance, and if so how much weight to use
and where to put it to balance the wheel.
• Correct the balance: Install the weights recommended by
the machines display, using the correct fixing method for
the weights.
• Recheck: Again rotate the wheel to check for accuracy of
the balancing and to confirm that balance has been
achieved (A reading of zero on both sides of the wheel
means the wheel is ready to reinstall on the vehicle)
• Repeat the process for the rest of the wheels and tyres.
• Refit the wheels and tyres to the vehicle applying proper
rotation
Wheel Balancing Procedure
8. Balancing Weight Material
• Lead: Very high Density (11.3), small size for given weight,
highly toxic and hazardous, not used now
• Steel: High Density (7.8), non toxic, non hazardous, prone to
corrosion, easily recyclable, poor appearance, widely used
• Zinc: Low Density(6.6), non toxic, low hazard, corrosion
resistant, good appearance, widely used
