Examkin

Question

Difficulty: MediumWheels and Tires

During a routine vehicle maintenance check, a technician observes that the raised rubber wear indicator bars molded into the bottom of the tread grooves are completely flush with the surrounding tread ribs. What does this condition indicate about the tire?

  1. A
    The suspension shock absorbers are worn out and allowing wheel bounce
  2. B
    The brake caliper is binding and causing friction flat spots
  3. The tire tread has worn down to 2/32 inch and the tire must be replacedAnswer
  4. D
    The differential assembly is slipping and scrubbing the outer tire edges

Answer

The tire tread has worn down to 2/32 inch and the tire must be replaced.
Tread wear indicators (wear bars) are molded across the base of the tire grooves at precisely 2/32 of an inch. When normal abrasive wear reduces the outer tread ribs until they are level with these bars, the tire has reached the legal minimum tread limit and must be replaced for safety.

Step-by-Step Solution

1
Identify the purpose of molded wear indicator bars in automotive tires.
Tread wear indicators are transverse rubber ridges molded into the primary longitudinal grooves at an exact height of 2/32 inch (1.6 mm).
Manufacturers build wear indicators directly into tires to provide a quick visual gauge of minimum legal and safe tread depth without requiring a dedicated depth gauge.
2
Evaluate the condition described where the wear bars are flush with the surrounding tread ribs.
The remaining usable tread groove depth is equal to or less than 2/32 inch.
When the tread surface wears down to the level of these indicator bridges, the tire cannot effectively channel water away, dramatically increasing the risk of hydroplaning and signaling required replacement.

Key Concept

Tread Wear Indicators and Minimum Tread Depth
Estimated Time:1m 0s
Rate this question

Topics

Wheels and Tires

More questions from this topic