Definition
The coupling plate on a tractor or dolly that locks around a trailer kingpin.
Practical example
Example: The driver checks the fifth wheel for secure mounting, lubrication, damage, and closed locking jaws.
Why it matters
A correct fifth-wheel connection is essential to prevent trailer separation.
Fifth Wheel in CDL training
CDL students should be able to recognize this term, explain it in plain language, and connect it to safe vehicle operation, inspection, licensing, or freight work as applicable. Review the term in context and practice using it during classroom study and hands-on training.
Frequently asked questions
What does Fifth Wheel mean in trucking?
The coupling plate on a tractor or dolly that locks around a trailer kingpin.
Why should a commercial driver understand Fifth Wheel?
A correct fifth-wheel connection is essential to prevent trailer separation.
This glossary is educational. Always follow current federal and state rules, the vehicle manufacturer’s instructions, and your motor carrier’s procedures.