CDL · Doubles and triples
Before coupling, how high should the trailer sit compared with the converter dolly's fifth wheel?
Correct answer: Just under the fifth wheel's center, so the dolly raises the trailer slightly as it goes under.
Answer options
- AEven with the upper surface of the fifth wheel, so the dolly can slide under without touching it.
- BJust under the fifth wheel's center, so the dolly raises the trailer slightly as it goes under. Correct
- CAs high above the fifth wheel as the landing gear allows, so the dolly has plenty of clearance.
Why
With the trailer a touch lower than the middle of the fifth wheel, the dolly picks it up slightly as it goes under. A trailer that sits too high may not couple correctly, while one that is far too low can be struck and damaged.
About this question
Topic: Doubles and triples License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
Practice the whole set
This question is part of Trailer Air Lines and Coupling (28 questions). Take the full set and check your score.
Practice Trailer Air Lines and CouplingMore questions from Trailer Air Lines and Coupling
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- What must you confirm right before backing the tractor under a trailer?
- You are coupling to an older trailer and accidentally cross the air lines. What is the result?
- Which sequence is correct for testing the trailer service brakes?
- Which statement about air-braked semi-trailers built before 1975 is true?
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