Here’s Your Complete Guide to Fifth Wheel Coupling

Here’s Your Complete Guide to Fifth Wheel Coupling

There are several critical safety aspects to heavy vehicle combinations, one of which is couplings. Understanding fifth wheel couplings is vital to the safety and efficiency of any trucking fleet. We’ll dive into the world of fifth wheel coupling and what some of the best products on the market currently offer. 

What Is Fifth Wheel Coupling?

The technology of fifth-wheel coupling provides the connection between a semi-trailer and the towing truck, tractor unit, leading trailer, or dolly. A fifth wheel connects the two components, allowing them to articulate, move around, and steer comfortably.

Without a fifth wheel, it would be almost impossible for a semi-truck to make a turn. A fifth wheel evenly distributes weight between a semi-tractor and trailer so you can hit the road and navigate your equipment. 

What Does a Fifth Wheel Coupling System Consist Of?

As a whole, the fifth wheel coupling system consists of the fifth wheel and the kingpin.

  • Fifth wheel – This equipment is a flat, non-rotating horseshoe-shaped coupling device installed on the semi-truck tractor.
  • Kingpin – A metal component that protrudes from the trailer that’s frequently referred to as the “pivot point between the tractor and semi-trailer.” 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. 

Invest in High-Quality Coupling Systems With Advanced Technology

When you need to invest in high-quality coupling systems with top-of-the-line technology, look no further than JOST International. Our JSK37UBK Series wheel is revolutionary – it allows the driver to know when the fifth wheel is properly and safely coupled from inside the cab. The sensor technology in the wheel sends a signal to a display in the cab that lets the driver know when the wheel is properly coupled.


  • Throat Illumination (sold separately) – An LED Light shines into the throat to allow clear inspection of the coupled fifth wheel. 
  • Go Light – A green light indicates the fifth wheel is properly coupled, with both kingpin and handle in the locked position.
  • No-Go Light – A flashing red light with an audible alert indicates that the kingpin and/or handle are not properly coupled. 

Capacities & Ratings:

  • Maximum Vertical Rating: 55,000 lbs
  • Maximum Horizontal Rating: 150,000 lbs

How It Works:

  • The Loc-Light system enhances your JOST fifth wheel with the addition of our two-sensor monitoring system as well as a LED throat illumination. 
  • The dual-sensor system is connected to the Go/No-Go indicator light located next to the handle. A proper coupling with the handle and kingpin in the locked position will be lit up as green or “Go light”. If the system does not detect the handle and/or kingpin in the proper locked position, the light will flash red or “No-Go light” 
  • The throat illumination light option (sold separately) automatically turns on when the system is engaged. The light shines directly into the throat of the wheel to provide a better view of the lockbar for pre-trip inspections.

If you need to know how to couple and uncouple JOST fifth wheels, take a look at our instructional video.

Looking For More Coupling System Information?

If you’re looking for more information about JOST International’s coupling systems and top-notch technologies, contact us today. Our experienced team members would happily listen to your needs and share how we can help. We offer an expansive range of fifth wheels, kingpins, turntables, landing gear, coupling systems, and more. 

Follow This Fifth Wheel Inspection Checklist Before Hitting the Road

Follow This Fifth Wheel Inspection Checklist Before Hitting the Road

When you want to set yourself up for a safe, successful trip, performing a thorough fifth wheel inspection is key. It can be a little daunting but necessary for any semi-trailer driver. We’re here to help walk you through the complete fifth wheel inspection checklist. 

What Is a Fifth Wheel Inspection Checklist?

A fifth wheel inspection is a process of carefully examining your vehicle and its components and systems. This checklist usually takes about 15 minutes to complete and is required by the Federal government. 

Why Are Fifth Wheel Inspections Important?

If you’re a semi-trailer driver, you know that the job comes with a lot of responsibility, which isn’t as easy as it looks. Performing fifth wheel inspections before trips is essential for many reasons, including:

  • Safety – Driving a semi-trailer can be dangerous. According to the Bureau of Labor Statistics, drivers of heavy trucks and tractor-trailer trucks suffer fatal accidents more than any other occupation. Making sure all your equipment is in proper working order can be the difference between a safe trip and getting into an accident.
  • Maintenance – Performing the checklist allows you to find minor issues before they become serious. This can save you money on maintenance by solving problems before your trucks get on the road.
  • Compliance – Pre-trip inspections keep you in compliance with the Department of Transportation regulations. In the case of an audit, the DOT may review your pre-trip inspection checklist to ensure they have been filled out correctly. 

What Does a Fifth Wheel Inspection Checklist Include?

You must thoroughly check each major system when performing your fifth wheel inspection. This process includes:

Engine Compartment

  • Check for leaks in the engine compartment.
  • Ensure every component is properly mounted and secured, including the water pump, power steering pump, alternator, front suspension system, and front brake system. 
  • Look for leaks in hoses.
  • Make sure all the tires, rims, and axles are in good shape and working correctly.

Fuel Tank And Battery Area

  • Inspect fuel tanks, caps, batteries, and exhaust systems and ensure they’re working properly.
  • Ensure mirrors, door hinges, and door handles are not damaged.
  • Look at the exhaust system, driveshaft, catwalk, frame, cross members, and gaskets for any malfunctions.
  • Check that the suspension system, brake linings, changers, slack adjusters, and pushrods are properly working.

Coupling System

  • Ensure that electrical lines and airlines are good to go.
  • The fifth wheel should be greased appropriately and have no gap between the fifth wheel and the trailer apron.
  • Make sure the skid plate of the fifth wheel and apron of the trailer are working properly.
  • Inspect the kingpin, mounting bolts, and locking pin. 


  • Check that landing gear, frames, cross members, mudflaps, and the rear door are ready for travel. 


  • Inspect turn signals, four-way flashers, brake lights, high beams, low beams, and brake lights.
  • Ensure that reflectors, reflective tape, and the color chamber are in good condition.

Fifth Wheel Inspection Checklist Resources

If you want more resources regarding fifth wheel inspection checklists, we’ve provided some below.

Check out our helpful JOST International instructional videos to make sure your fifth wheel, landing gear, and coupling systems are in proper working order. 

Take a look at this helpful Semi-Trailer Pre-Trip Inspection Checklist. In addition to ensuring your fifth wheel, landing gear, and major systems are in good working order, you should also inspect these elements of your semi-trailer before embarking on a trip. 

fifth wheel inspection checklist sheet

JOST International Is Here for All Your Semi-Trailer Needs

Once your pre-trip inspection is complete, you’re ready to hit the road! If you need any replacement parts for your semi-trailer, look to JOST International. We have a long history of developing efficient, safe, and innovative systems for trucks and trailers, including fifth wheels, landing gear, coupling technologies, kingpins, and more.