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Difficulty: MediumWheels and Tires

A service apprentice is using an off-car computerized spin balancer to balance an assembled wheel and tire. What is the correct order of steps required to properly execute this dynamic wheel balancing procedure from start to finish?

  1. 1Clean the wheel hub mating area and securely mount the assembly onto the balancer arbor using the appropriate centering cone.
  2. 2Measure and enter the wheel assembly parameters—offset distance, rim width, and rim diameter—into the balancer computer.
  3. 3Lower the protective safety hood and spin the wheel assembly to measure static and dynamic imbalance.
  4. 4Rotate the wheel to the indicated positions and attach the specified counterweights to the inner and outer rim planes.
  5. 5Lower the hood and perform a second spin cycle to verify that the imbalance readings on both planes are zeroed out.

Answer

The correct procedural order is: clean the mating area and mount the wheel using the proper cone, input the rim dimensions into the computer, lower the hood to run the measurement spin, attach the indicated counterweights to the rim planes, and respin the assembly to verify zero imbalance.
Computerized dynamic balancing requires a strict procedural sequence: mechanical setup (mounting and centering the wheel), electronic calibration (entering offset, width, and diameter), baseline measurement (initial spin with safety hood lowered), corrective action (attaching counterweights at designated inner/outer plane locations), and quality verification (final spin confirming zero imbalance).

Step-by-Step Solution

1
Center and clamp the wheel on the balancer arbor using the correct back or front cone.
The wheel assembly runs true without mechanical runout or off-center mounting error.
Improper mounting causes false imbalance readings and improper weight placement.
2
Use the machine gauges/calipers to record rim offset, rim width, and rim diameter, then enter them into the interface.
The computer calibrates its calculations to the exact dual-plane geometry of the wheel.
The machine cannot calculate the weight split between inner and outer planes without accurate dimensional data.
3
Lower the safety hood to initiate the high-speed measurement spin.
Sensors register the force vectors and output the required weight values and clock positions.
The hood engages the safety interlock and allows the wheel to spin safely up to measurement speed.
4
Align the wheel with the top-dead-center (or laser-guided) indicator and affix clip-on or adhesive tape weights.
Correction mass is added directly opposite the heavy spots on both rim planes.
Adding weight directly counteracts centrifugal forces generated by uneven tire/wheel mass distribution.
5
Close the hood and re-spin the assembly.
The digital display confirms OK or 0.00 on both inner and outer display windows.
Verification ensures that the attached weights fully eliminated dynamic imbalance without requiring further correction.

Key Concept

Off-Car Computerized Dynamic Wheel Balancing Sequence
Estimated Time:1m 30s
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Topics

Wheels and Tires

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