Why Is A Fifth Wheel Called A Fifth Wheel?

Have you ever heard the phrase “fifth wheel” but didn’t quite understand what it meant? Or perhaps you’ve seen a fifth wheel trailer and wondered why it was even called that? The term “fifth wheel” has a surprisingly long and interesting history, and it’s an interesting thing to explore.

In this article, we’ll explore the origins of the phrase “fifth wheel” and just why it was named that way. Keep reading to learn more about this fascinating piece of etymology.

Why Is A Fifth Wheel Called A Fifth Wheel?

A fifth wheel is a vehicle coupling mechanism that adds an extra wheel to a trailer – making it more stable and maneuverable when towing.

The term “fifth wheel” has become a frequently used metaphor for someone or something who is not essential to a group, like an extra burden or a third wheel. But how did this term come about? In this article, we’ll explore the origins of the phrase “fifth wheel” and explain why it’s called that today.

Origins of the Fifth Wheel

The fifth wheel was first seen in the late 19th century when horse-drawn wagons began to be outfitted with extra wheels. This was a common sight in Britain, where one extra wheel was equipped in the middle of a wagon, beneath the driver’s bench. The extra wheel provided support and increased the stability of the wagon during heavy-duty hauling.

In 1897, a device called the American Fifth Wheel Coupling was invented by engineer William Briggs. This early fifth wheel was composed of a cast steel or malleable iron basket that connected to the wagon’s main wooden axles.

The device allowed a team of horses to pull heavy loads more easily, as the basket could bear more weight than the axles alone.

Modern Fifth Wheels

Today, fifth wheels are commonly seen in the form of recreational vehicles (RV) and trucks. These devices are equipped with a locking mechanism that allows them to engage with the trailer, providing additional stability and allowing the vehicle to turn sharper corners than a vehicle with a single axle.

While modern fifth wheels rely on a mechanical locking system instead of a basket, they still refer to their predecessors when they are referred to as “fifth wheels”. This term refers to the fifth wheel providing the extra stability needed to maneuver rough terrain or carry heavy loads.


The term “fifth wheel” originated in the late 19th century and was used to refer to an extra wheel that was attached to a wagon to provide extra stability. Today, this term is used to refer to modern fifth wheels, which provide additional support and stability for vehicles like recreational vehicles and trucks. Overall, the term “fifth wheel” has an interesting origin story and is used to refer to a vital device attached to many vehicle types today. Citation URLs:- https://www. thedrive. com/news/23145/what-is-a-fifth-wheel-trailer- https://en. wikipedia. org/wiki/Fifth_wheel_(vehicle_coupling)- https://www. azbilliards. com/pool-billiard-glossary/fifth-wheel/

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