High-speed vibration is typically caused by imbalance or radial force variation.
Static vs Dynamic Imbalance
- Static imbalance → vertical hop
- Dynamic imbalance → lateral wobble
Measured in grams using electronic balancers.
Even 10g imbalance at 70 mph creates significant centrifugal force.
Radial & Lateral Runout
Using dial indicators, technicians measure:
- Radial runout (up/down movement)
- Lateral runout (side movement)
Acceptable tolerance:
- Typically <1.5mm for most passenger vehicles
Excessive runout causes:
- Steering wheel vibration
- Suspension wear
- Uneven tread wear
Torque Accuracy Matters
Improper torque causes:
- Warped brake discs
- Hub distortion
- Wheel detachment risk
Torque should be applied using:
- Calibrated torque wrench
- Manufacturer specification pattern (star sequence)