Question:
Where did the fifth wheel get its name? In other words why is a "fifth wheel" called a "fifth wheel"?
Thanks

Answer:
Probably goes back to the old, old days when "trucks" still had 4 wheels. When the "attachment" came along, someone stuck the name "5th wheel" on it, 'cuz I guess it kind of does look like a wheel...sorta.
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I'm not a truck driver, I'm a professional tourist!

Answer:
I dont know but I always figured it had something to do with the fact that it allowed the trailer to pivot and turn kinda like a wheel or something. You got 4 wheels turning on the ground and fifth wheel that lets your trailer turn.. that's the conclusion I've reached after pondering that very same question behind the windshield for many miles riding down the road lol

Answer:
I started thinking about it too. So I grabbed my trusty Webster and it appears the term fifth wheel precedes the trucking industry to the horse and buggy days.
fifth wheel - 1 - a) a horizontal wheel-like structure placed over the front axle of a carriage or wagon to support it on turns.
b) a similar structure on the rear of the cab of a tractor-trailer, serving as a coupling for attaching the trailer.
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