What should be the minimum tread depth for front tires?
- 2 mm
- 3 mm ✓
- 4 mm
- 1 mm
Answer: B. 3 mm
The minimum tread depth for front tires is 3 mm.
Why this is the answer
The handbook lists tire defects for commercial vehicles. It says a front tire is defective when it has less than 3 mm (1/8 in) of tread and the vehicle has a GVW of 5,500 kg or more. That makes 3 mm the minimum shown for front tires in this situation. The passage does not say a front tire needs 4 mm, and it treats 2 mm or 1 mm as below the stated limit. Checking tread depth helps you avoid running tires the handbook calls defective.
Why the other answers are wrong
- A. 2 mm — A front tire with 2 mm of tread is below the handbook's stated 3 mm minimum and is therefore defective.
- C. 4 mm — The handbook sets the front tire minimum at 3 mm, not 4 mm, so 4 mm is higher than the required minimum.
- D. 1 mm — A front tire with 1 mm of tread is well below the stated 3 mm minimum and is defective.
Remember it
Front tires get the higher number: keep them at or above 3 mm.