Getting To Know Your Fifth Wheel

Semi-Truck Fifth Wheels and Why They're Important

If you know trucks, then you know how important semi-truck fifth wheels are to keep maintained. Designed to make sure that your trailer moves easily when you make turns, fifth wheels are an integral part in making sure you can comfortably and safely maneuver your vehicle at any speed.

To help you learn a little more about fifth wheels, our team of trucking experts have put together the following article for you to look through. Read on to learn more about the fifth wheel in your semi-truck!

What is a Semi-Truck Fifth Wheel?

The fifth wheel on your semi-truck's trailer is the plate above the back wheels where the kingpin locks onto the tractor. The fifth wheel allows the tractor to turn with the trailer still attached. They are also made to distribute the trailer's load evenly across the tractor and trailer so that the operator can safely maneuver.

How Does A Fifth Wheel Work On A Semi?

Your semi-truck's fifth wheel is the main connection point between the tractor and trailer. To understand how this works, there are a few key components to consider.

The first component you'll want to think about is the kingpin. The kingpin is a metal piece that protrudes from the trailer.

The fifth wheel is where the kingpin engages. It is a flat, horseshoe-shaped coupling device that is installed on the semi-truck tractor and does not rotate.

The kingpin on the trailer is hooked into the fifth wheel on the tractor. The semi trailer's surface, with the kingpin at the center, rotates against the fifth wheel, which faces upwards. Grease reduces friction between the two components and works to extend the life of both the kingpin and the fifth wheel.

What's the Difference Between a Sliding and Fixed Fifth Wheel?

Even though they both perform the same function, sliding fifth wheels and fixed fifth wheels each accomplish their individual goals differently.

If you are hauling a similar sized load for most of your runs, a fixed fifth wheel will do the trick. However, if you're dealing with varied load types, then a sliding fifth wheel is the way to go when you are choosing specifications for your truck.

Sliding Fifth Wheels: Sliding fifth wheels are developed to support a wide array of load weights. They are designed to slide backward and forward to facilitate smooth hauling. As the fifth wheel slides forward or backward, it can more effectively distribute the weight of light or heavy loads.

Fixed Fifth Wheels: A fixed fifth wheel stays locked in the same place on a semi-truck tractor. It is fixed to the vehicle and is typically used in trucks haul about the same size load. Since the load is the same for most of your trips, there's no need to adjust the fifth wheel to accommodate a variety of load types.

Why is it Called a Fifth Wheel?

The name originally comes from the company that first used the fifth wheel hitch type in the early 1900s. The Martin's Fifth Wheel Company named the fifth wheel after the round shape of the hitch. Prior to the introduction of the new kingpin design, the device itself was in the shape of a wheel.

What are the Five Essential Components of a Fifth Wheel?

There are a multitude of options available for you to choose from when you are determining which truck has the right fifth wheel type for your needs. Since all fifth wheels are manufactured a little differently, we're going to dive into the 5 essential parts of a fifth wheel. This should give you the information you need to find the best fifth wheel for your unique application.

1. Top Plate: The top plate on your fifth wheel is the cast part of the device. It typically looks like a large horseshoe. The top plate is designed to secure the coupling components and vertical trailer load. The top plate is the largest component in a fifth wheel.

2. Hitch Head: The hitch head is made with a jaw that funnels the trailers' king pin in order to establish a secure connection with the pickup, the fifth wheel hitch, and the trailer.

3. Base: The base component is where the head rests. Some fifth wheel hitches can move back and forth, while some can also move side to side on the base.

4. Legs: The legs attach to the base and hitch head combination to the rails.

5. Rails: The rails attach the fifth wheel to the bed.

Read More About Fifth Wheels

If you are looking to learn a little more about the fifth wheels in your semi-truck, then you've come to the right place. In order to help you gain as much knowledge as possible, our team of experts will be bringing you a full article on each of the components that make up the fifth wheel system. Click any of the links below to read more about fifth wheel components!

· Getting To Know Your Fifth Wheel: Top Plates

· Getting To Know Your Fifth Wheel: Landing Legs

Shop Fifth Wheel Parts Today!

For those looking into replacement parts for their semi-truck, you've definitely found yourself at the right location. No matter what fifth wheel component you've had your eye on for your semi-truck, we have a full selection for you to choose from. Whether you are looking for top plates, king pins, or landing legs, we'll have it from some of the most notable brands in the industry. Login or create an account to start saving on your next fifth wheel component today!