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Doubles & Triples Practice Question 21

TDoubles & Triples · Question 21

A pre-trip air check on a triples combination should include:

• AA leak-down test with all units coupled and charged
• BOnly test the tractor
• COnly test the first trailer
• DSkip and drive

Correct answer: A. A leak-down test with all units coupled and charged

Why: Charge the entire combination and perform leak-down with all units. Air loss anywhere shows up here. Allowed leak rates differ from singles.

How this question fits the Doubles/Triples test

Each additional articulation point multiplies rearward amplification. A driver pulling triples must steer earlier, brake sooner, and inspect twice as much equipment as a single-trailer driver.

Study technique for this topic

Learn the correct trailer placement order by weight, the procedure for converting a single to a double, and the special inspection items unique to converter dollies and pintle hook assemblies.

Related Doubles/Triples practice questions

• Q10. When uncoupling triples, you should:
• Q24. The order of trailers (besides weight) may also be set by:
• Q37. A bobtail tractor going to pick up the first trailer should:
• Q50. You should never tow a trailer with:
• Q3. The heaviest trailer in a doubles or triples combination should be:

Continue your CDL preparation

The Doubles & Triples portion of the CDL knowledge exam covers more than this single question. Use this site's full Doubles & Triples bank to drill every topic, then test yourself with one of our state-specific practice sets to confirm you are ready for the actual DMV exam in your state. Always check your state's CDL handbook for any local addenda before the test day.

If you are still building your overall CDL foundation, start with the General Knowledge bank — every CDL applicant must pass it — and then work outward to the endorsements you plan to add.