Wheels, Tires, and Hubs
Tire wear patterns, TPMS, wheel bearings, seals, and hub maintenance.
- Interpret tire wear patterns and identify their causes
- Describe TPMS function and minimum tread depth requirements
- Explain wheel bearing types, adjustment procedures, and seal function
- Identify causes of hub oil leaks
Leçon 1
Tire Wear Patterns and Inspection
Reading Tire Wear
Tire wear patterns tell the story of what is happening with alignment, inflation, and suspension. Understanding these patterns is essential for diagnosis and is heavily tested on the Red Seal exam.
Center wear indicates over-inflation - the center of the tread bulges out and contacts the road more than the edges. Edge wear (both sides) indicates under-inflation - the tire flexes more at the edges. Inside edge wear indicates excessive negative camber or toe-out.
Center Wear
Cause: Over-inflation
Fix: Reduce to specified pressure
Both-Edge Wear
Cause: Under-inflation
Fix: Inflate to specified pressure
Inside Edge Wear
Cause: Negative camber or toe-out
Fix: Alignment correction
Minimum Tread Depth
The minimum tread depth for steer tires is 4/32 inch. Drive and trailer tires have a minimum depth of 2/32 inch. Steer tires have a higher minimum because they are critical for directional control and water evacuation in wet conditions.
Inside edge tire wear is caused by excessive negative camber or toe-out. The minimum tread depth for steer tires is 4/32 inch - higher than the 2/32 inch minimum for drive and trailer tires.