CDL General Knowledge TestCombination Vehicles (if applicable)Hard
What is the maximum acceptable amount of play (movement) for a properly coupled kingpin within the fifth wheel jaws?
- AUp to 1/4 inch.
- BUp to 1/8 inch.
- CNo discernible play should exist.
- DUp to 1/2 inch.
Show answer & explanationAnswer & explanation
Correct answer: C. No discernible play should exist.
For a properly coupled kingpin and fifth wheel, there should be no discernible play or movement. Any play indicates wear or an improper connection, which can lead to chucking, damage, or even uncoupling.
Why the other options are wrong
- A. 1/4 inch is excessive and dangerous.
- B. Even 1/8 inch of play is too much and indicates wear or an issue.
- D. 1/2 inch is grossly excessive and would be an immediate out-of-service violation.
Kingpin Play Limit
A properly coupled kingpin should have no discernible play within the fifth wheel jaws.
- Any play indicates wear or improper connection.
- Play leads to chucking and damage.
- Critical safety check.
- Requires immediate attention if found.
Memory trick: Tight as a drum, safe as a ride.