A Complete Guide to the Most Common Types of Fifth Wheels

A Complete Guide to the Most Common Types of Fifth Wheels

If you work in the semi-trailer industry, you’re familiar with fifth wheels. But do you know what types of fifth wheels are on the market? From stationery to sliding, we’ve got them all. Plus, besides JOST International, other brands make their own models as well. Here are the types of wheels explained. 

Types of Fifth Wheels Explained: JOST International

At JOST International, we’re proud to be a world market leader and international supplier for the commercial trucking industry. We provide top-of-the-fifth wheels that accommodate various applications – sliding fifth wheels and stationary fifth wheels.

Sliding Fifth Wheels

A sliding fifth wheel is a coupler that connects the tractor unit and semi-trailer together. It features a mechanism that slides the coupler forward and backward. Sliding fifth wheels are mounted to the semi-tractor’s frame. Unlike a stationary fifth wheel, it can move along the frame rails.

Advantage: Sliding fifth wheels help transfer weight to or from the steer (front) axle when customers change trailer types or have variable loads. The number of options for customers and revenue opportunities are increased.

JOST sliding fifth wheel

Stationary Fifth Wheels

Stationary mount fifth wheels, also known as fixed fifth wheels, are the original fifth wheel. These fifth wheels are ideal for applications where the semi-trailer’s kingpin setting, axle loading, and vehicle length are all constant throughout the fleet. As a rule of thumb, stationary fifth wheels are lighter than sliding mount fifth wheels.

Advantage: Stationary fifth wheels offer greater weight savings and maintenance simplicity. Customers increase revenue through greater payload and reduce operating costs with greater simplicity.

JOST stationary fixed wheel

For more information about our products, download our Fifth Wheel Product Line handout. 

Identifying Types of Fifth Wheels

JOST fifth wheels are standard products for many trucking companies. There are also other brands on the market that produce quality fifth wheels, including Holland and Fontaine. If you need to identify a type of fifth wheel, here’s how to do so:

JOST International Fifth Wheels

Every JOST fifth wheel has a unique red identification tab with the item’s model and assembly numbers. It will also have the JOST logo cast in the top surface or prominent on the ID tag.

Every JOST International genuine-made component meets the strictest OEM first-fit requirements for specifications. We make an array of compatible replacement parts for other brands of fifth wheels.

JOST logo fifth wheel

Invest in Industry-Leading Fifth Wheels

When it comes to types of fifth wheels for semi-trailers, JOST International is the industry leader. We’ve been manufacturing fifth wheel coupling devices globally since 1956, and we even submitted the patent for the very first steel-cast fifth wheel coupling. 

If you’re looking for more information about JOST fifth wheels, we’re here to help. Take a look at our inventory of fifth wheel products or contact our team today.

Download the jost fifth wheel catalog

A comprehensive look into each of the JOST fifth wheel products.

How to Winterize Your Fifth Wheel

How to Winterize Your Fifth Wheel

Freezing temperatures can take their toll on your rig, but don’t fret – winterizing your semi truck’s fifth wheel will help prevent damage and save you time and money throughout the season. Read on to discover our tips for semi fifth wheel winterization so you can face the elements with peace of mind. 

Your Go-To Guide for Fifth Wheel Winterization

States in cold climates use aggressive road salts for snow removal. These salts contain magnesium and calcium chlorides that can quickly develop corrosion on tractor and trailer components. The corrosion will adversely affect a semi truck’s fifth wheel’s performance if left unchecked. 

Don’t let your fifth wheel get damaged during the winter season. Winterize your semi fifth wheel and follow the following recommended inspections and preventive maintenance guidelines:

  • Thoroughly degrease and clean the top plate surface and underside using a steam-cleaning device and other suitable degreasing products. Be sure to remove any grease buildup within and around the lockjaw, throat, and pivot points.
  • Use an aerosol cleaner to clean the retractable release handle where the plate extends along the pins.
  • Inspect all areas and parts of the fifth wheel for damaged or missing parts, and if necessary, replace them with genuine JOST parts. 
  • Spray a penetrating oil, such as PB Blaster or Kroil, and lubricate both pivot points underneath the top plate, both slide plungers inside the plunger housings, the slide track, and the center pivot post where the pivot arm rotates. 
  • Verify that the lock closes completely and is operating correctly.
  • Apply lithium-based grease with an EP (extreme pressure) additive to the trailer contact surface of the fifth wheel.
  • Thoroughly degrease and clean the slide track and engagement rack, as well as the plungers and plunger housings using a shop steam cleaning device and suitable degreasing products. Be sure to remove any grease buildup in the slide release mechanism that would inhibit the free rotation of the pivot arm.

How to Service Your Air Supply System

Before the winter season kicks in, it’s also vital that you inspect your air supply system and perform any necessary repairs and maintenance. Follow these steps below to set yourself up for success: 

  • Drain out all of the water from the air tanks.
  • Confirm that all air tank lanyards are attached. 
  • Confirm that the air drier cartridge is less than three years old. 
  • Confirm that the air drier heat element is working correctly. 
  • Remove all the water from the air lines supplying the top plate and slider air release cylinders. 

Other Ways to Winterize Your Semi-Truck

In addition to fifth-wheel winterization, you should prepare other parts of your truck for the harsh winter elements. These are our best tips for preparing for the season:

  • Check your battery and electrical systems and perform any maintenance if necessary.
  • Look over the fuel filter and water separator to ensure everything works properly. 
  • Start using fuel additives.
  • Inspect the cooling system for any necessary repairs.
  • Prepare your windshield and install new wipers or wiper fluid if necessary.
  • Check your tires’ condition and pressure level.
  • Pack an emergency tool kit. 

Invest in High-Quality Fifth Wheels From JOST International

Set yourself up for success this winter and invest in a JOST International fifth wheel. JOST has been manufacturing fifth wheel coupling devices globally since 1956, and we were the first to patent steel-cast fifth wheel coupling. We’ve continued our dedication to innovation ever since with new technologies and exceptional safety features that respond to the needs of our customers. From our unique locking mechanism to our new sensor fifth wheels, our fifth wheels are a standard option at every OEM.

Download our Fifth Wheel Product Line handout to learn more about each product, or give our team a call today!

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

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.