Manual vs. Air Release Fifth Wheels: Discover the Best Option for You

Manual vs. Air Release Fifth Wheels: Discover the Best Option for You

For years, manual lever-style fifth wheels were the go-to product in the semi-trailer business. Today, air-release fifth wheels have been introduced, providing convenience. So, what’s the difference between manual and air-release fifth wheels, and which option is best for you based on your application? We’re here to tell you all about it. 

Comparing Manual vs. Air-Release Fifth Wheels

The world of semi-tractor equipment has significantly evolved in efforts to improve efficiency and driver safety. One of the new pieces of technology is the air-release fifth wheel. Let’s compare manual and air-release fifth wheels. 

What Are Manual Release Fifth Wheels?

The main difference between manual fifth wheels and air-release fifth wheels is the coupling technology. With manual-release fifth wheels, you may verify that it’s coupled properly by doing a tug test. You should also visually inspect the fifth wheel to be sure. You’ll ensure the locking bar fully crosses the throat, all visual lock indicators are engaged (JOST 5th Wheel Lock Security Link), and check that there’s no air gap between the bottom of the trailer and the top of the fifth wheel. 

To uncouple this fifth wheel, the lock is released manually by pulling a handle on the fifth wheel. 

The Cons of Manual Release Fifth Wheels:

  • There are so many different products on the market, each with its own unique locking operation. Knowing what to check for can be confusing for drivers, thus resulting in safety risks. 
  • The manual lever style is more difficult for the operator to use – it involves more physical work, and it’s challenging to couple and uncouple.

What Are Air-Release Fifth Wheels?

JOST International air-release fifth wheels are favored for their state-of-the-art sensor technology. The sensors are paired with a coupling system that helps the driver confirm that the fifth wheel is properly attached and safely from inside the cab. No more tug tests or visual inspections under the trailer are needed! 

The Sensorkuppling and Lok-Lite systems contain dual sensors. The first sensor indicates that the kingpin is securely in the lock position. The second sensor shows that the fifth wheel is locked and the release handle is secured (JOST 5th Wheel Lock Security Link). The status of the lock is indicated by a JOST-supplied dash display, communicated through the vehicle’s CAN bus or via lighting at the top plate. 

To uncouple the device, air pressure is applied through a valve inside the cab. The driver can safely uncouple without even having to exit the vehicle! 

The Pros of Air-Release Fifth Wheels:

  • A safety system interlock requires the truck to be stopped and the trailer brakes applied before cab controls can be activated.
  • An automatically engaging secondary lock ensures security.
  • A visual lock indicator will confirm proper locking, so you can always be sure you’re good to go.
  • The fifth wheel can be rebuilt in under an hour without taking it off the truck – this significantly improves productivity. 
  • The throat cushion ring reduces wear on the kingpin and absorbs impact.
  • The full-size release handle allows for quick, easy, and convenient manual release.
  • JOST air-release fifth wheels are available for specification at all major OEMs.
  • Insurance costs and claims are reduced.

Air-Release Fifth Wheels From JOST International

As you can see, there are many advantages when you use air-release fifth wheels. From large national fleets to owner-operators, more and more semi-trailers are opting for JOST International air-release fifth wheels. Are you interested in learning more about JOST International air-release fifth wheels? Take a look at our brochure or contact our team today!

How To Adjust a Fifth Wheel 101: Everything You Need To Know

How To Adjust a Fifth Wheel 101: Everything You Need To Know

The fifth wheel on a semi-trailer refers to the mechanism that connects the tractor to the trailer. It’s where the kingpin is located, allowing the two parts to stay connected and move safely and freely when steering the vehicle. It also helps to evenly spread the freight load’s weight between the tractor and trailer.

If you notice that your fifth wheel is starting to get slack in it, it’s probably time for adjustment. We’ll tell you everything you need to know about how to adjust a fifth wheel.

Why Do You Need To Adjust a Fifth Wheel?

Fifth wheels can be adjusted when you notice too much play or trailer sway is occurring. This means that when you move from stop to start, there is a considerable amount of jerk happening, or your trailer is fishtailing when you make turns.

This could be dangerous for you and your equipment, but knowing how to adjust the fifth wheel can solve this issue.

How to Adjust a Fifth Wheel

Typically, fifth wheels don’t need adjusting very often. If you find that it’s necessary, it can be done. It’s important to note that each manufacturer designs its fifth wheel differently, so instructions may vary between makes and models. For some, you simply have to turn a bolt. For others, specialized tools are required to make the adjustment.

How To Adjust a JOST International Fifth-Wheel

Since all fifth wheels vary slightly by manufacturer, we’ll give you a step-by-step on how to adjust JOST International’s fifth wheels. These may not be exactly the same steps for your coupling device, but they should give you a general understanding of the process.

Adjusting a JOST International Fifth-Wheel Step-By-Step:

  1. The fifth wheel is made up of the release handle, release arm, lock bar, and lockjaw. The lock adjustment screw is located on the side of the wheel.
  2. To tighten the adjustment, loosen the jam nut and turn the adjustment screw one full rotation counter-clockwise.
  3. Repeat as necessary and retighten the jam nut when finished.
  4. Remember: Always turn the adjustment screw counter-clockwise to tighten. If you turn the wrong way, it can damage the release arm.

Top-Notch Fifth-Wheels by JOST International

If you’re looking for the safest, most durable fifth wheels on the market, look no further than JOST International. Download our Fifth Wheel Product Line handout to learn more about each product. You can also contact our knowledgeable team to learn further. We’d be happy to assist you with all your fifth wheel and semi-trailer equipment needs.

fifth wheel catalog

Expert Reviewed On 5/23/23

Braydon Soule is the Inside Sales Manager at JOST International and has worked in the truck parts industry for over 15 years. In that time he has become an expert in truck and trailer technologies and products.

Braydon Soule

JOST International

5 Essential Parts of a Fifth Wheel

5 Essential Parts of a Fifth Wheel

A fifth wheel is a part that almost anyone in industrial trucking is familiar with. We know it works to connect the semi truck tractor and trailer, and if you’ve been in the business for a while, you might even be familiar with a few of the key features that are nice to have in top-of-the-line models.

But when there are so many options to choose from on the market today, it can be helpful to know what you truly need to have and what options are add-ons. 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.

01. Top Plate


The top plate is the cast part of the fifth wheel. It usually looks like a large horseshoe shape. The top plate secures coupling components and vertical trailer or cargo load. It’s the largest component of a fifth wheel.

02. Release Handle


Not all fifth wheels have this type of handle — the release handle (shown blue in the image above) is a unique part specific to JOST fifth wheels. In a JOST fifth wheel, the release handle makes it easy for operators to couple and uncouple a fifth wheel while ensuring ultimate safety.

The release handle also provides operators with secondary locks and visually indicates that the coupling is secure. While not all fifth wheels feature a release handle, JOST has prioritized this part for the safety and security of all our customers. When operators can visually confirm that tractor-trailer coupling is successful, there’s no guesswork, and you know you’re hauling safely.

03. Lever


The lever is a relatively small component of a fifth wheel, but that does not make it unessential. The lever links the release handle to the locking bar. Together, all three components work to slide the locking bar across the opening of the cushion ring, supporting and securing the lock jaw and ensuring the tractor and trailer are appropriately coupled for transit.

04. Lock Jaw


The lock jaw is the coupling mechanism that locks around the kingpin to hold it in place. In the above image, you can identify the lock jaw by it’s “C” shape. This shape allows the jaw to fit snugly around the kingpin. It is connected to the lever and release handle, and is the primary securing mechanism holding the tractor and trailer together.

05. Lock Bar

locking bar

A fifth wheel’s lock bar secures the lock jaw. When engaged, the lock bar slides across the opening of the cushion ring, under the lock jaw, and ensures the trailer kingpin is held firmly in the fifth wheel and is secure for transit. The lock bar provides superior structure to support trailer drawbar load.

Are these the only components of a fifth wheel?

While these five components are essential to the safe functionality of any fifth wheel, they are not the only components. For example, JOST fifth wheels also offer a range of features to ease operation and extend product life cycle, including:

adjustment screw
  • Adjusting Screw. This allows the locking bar to maintain a snug coupling even as the lock jaw and cushion ring wear.
  • Grease Fitting. This delivers grease directly to the kingpin and lock jaw contact point to ensure that all parts are properly lubricated to extend the life of both products.
  • Cushion Ring Insert. This works to protect the kingpin and top plate casting from wear and damage.

There are a number of additional components featured on JOST fifth wheels, but the five mentioned above are essential to the functionality of every fifth wheel. At its core, a fifth wheel must have:

  • A top plate for the trailer to rest on
  • A securing mechanism to hold and secure the kingpin
  • An operational mechanism that allows the driver to couple and uncouple tractor and trailer

With a better understanding of each of these components and their importance to the safety of your daily operations, you’ll be able to select the ideal fifth wheel product for your specific application’s requirements.

If safety and durability are priorities for your fleet, JOST fifth wheel products deliver. Check out our parts online, or get in touch with our team to find a dealer near you.

How Does a Fifth Wheel Work on a Semi?

How Does a Fifth Wheel Work on a Semi?

JOST International has been manufacturing fifth wheel coupling devices since 1956. In fact, we submitted the patent for the first-ever steel cast fifth wheel coupling. As a leading manufacturer of fifth wheels, we want to make sure that anyone in the industry, new or experienced, has access to helpful, informative content about all of our components. With that goal in mind, we’re tackling a popular question from those new to the semi-truck and industrial transportation industry: “how does a fifth wheel work on a semi?”.

We’ll cover everything you need to know, from what a fifth wheel is, to how it works and what kind of fifth wheel might be best for your application. Let’s start with the basics.

What is a Fifth Wheel?

Not to be confused with an RV trailer, a fifth wheel is an important component of a semi truck’s tractor. A fifth wheel is the plate above the tractor’s back wheels where a semi trailer’s kingpin hooks to the tractor. The fifth wheel is what allows the tractor to turn with the trailer still attached. A fifth wheel is also designed to spread the trailer’s freight load evenly across the tractor and trailer so that the operator can safely haul, no matter where they’re headed.

How Does a Fifth Wheel Work on a Semi?

As mentioned, a fifth wheel is a key connection point between a semi-truck tractor and trailer.

To understand how this works, it’s important to understand the key components.

First, you have a kingpin, which is a metal component that protrudes from the trailer.

Then, you have a fifth wheel, where the kingpin engages. A fifth wheel is a flat, non-rotating horseshoe-shaped coupling device that is installed on the semi-truck tractor.

The kingpin on the trailer installs into the fifth wheel on the tractor. The semi trailer’s surface, with the kingpin at the center, rotates against the upward-facing fifth wheel. Grease is applied to reduce the friction of these two components rubbing together and works to extend the life of both the kingpin and the fifth wheel.

Jost Fifth Wheel 2

What is the Purpose of a Fifth Wheel?

A fifth wheel has two key purposes:

  1. A fifth wheel connects the semi-truck tractor and trailer, while allowing both to articulate, move around, and steer comfortably. Without a fifth wheel, it would be almost impossible for a semi-truck to make a turn.
  2. A fifth wheel evenly distributes weight between a semi-tractor and trailer.

While the first purpose is fairly self-explanatory, the second can be a bit more complicated. Since every load is a little different, fifth wheels must accommodate to ensure that semi-truck weight is balanced appropriately. To do so, there are two key types of fifth wheels, fixed and sliding.

Fixed and Sliding Fifth Wheels: What’s the Difference?

Fixed and sliding fifth wheels perform the same function, but they do it a little differently.

A fixed fifth wheel stays in exactly the same place on a semi-truck tractor. It is “fixed” on the vehicle and is typically used for rigs that are hauling about the same size load, no matter what. Because the load is the same for every trip, there’s no need to adjust where the fifth wheel sits to accommodate different types of loads.

A sliding fifth wheel is designed to support a variety of load weights. They can slide backward and forward to facilitate safer hauling. As the operator slides the fifth wheel forward or backward, they can better distribute the weight of lighter or heavier loads.

In general, if you or your operators are hauling about the same size load for every run, a fixed fifth wheel is sufficient. But, if you’re an owner/operator, or if your team often deals with varied load types, then a sliding fifth wheel is likely the better option.

Looking for a New Fifth Wheel or a Fifth Wheel Replacement?

JOST International has you covered. As an industry leader in fifth-wheel innovation, we’re proud to supply the safest fifth wheels on the market, all of which feature our original locking mechanism for safe, simple use. From lightweight options to reinforced fifth wheel solutions built to stand the tests of time, get in touch with our team to find a dealer near you.