Wear and Damage on a Fifth Wheel and Kingpin

Kingpins and Fifth Wheels Susceptible to Wear and Damage

Commercial trucks and trailers are the backbone of our society. These semi-trucks connected to trailers are filled with all the essentials of life including food, clothing, medicine, and household goods. To keep them operating safely on our roads they require regular maintenance and repairs. 

Industries such as food service and grocery keep their fleets constantly moving. These industries experience a high wear rate on their kingpin and fifth wheels. The daily stops and tight locations that they navigate to make their deliveries results in added stress on the truck and trailer connection. To keep this wear manageable and the equipment in operational condition, established maintenance procedures must be followed. 

Metal on Metal = Wear & Damage

Many fifth wheels are made with cast steel and the kingpins are constructed with a controlled metallurgical composition. Manufacturers of these components have made many improvements over the years to improve the wear characteristics of these parts. However, anytime you have two metal objects that contact each other, you will inevitably experience wear and damage.

Semi-trucks and trailers are often connected and disconnected multiple times in a day while loading and unloading their cargo. This action creates the perfect environment for wear and damage. If a kingpin or fifth wheel is damaged during the connection process it can cause excessive wear. This damage can also continue to affect the rest of the fleet as the damaged truck or trailer connects to additional equipment.  

Properties of High Strength Steel

Fifth wheels on commercial trucks are often made with cast steel. 

According to the Reliance Foundry, “cast steels can be produced with a wide range of properties. The physical properties of cast steel can change significantly depending on the chemical composition and heat treatment. They are selected to match performance requirements of the intended application.”   

Manufacturers of fifth wheels attempt to balance the hardness of the material with the strength of the steel. The hardness of the material affects the ability of the material to withstand abrasion and the strength of the steel impacts the force necessary to deform the material. 

The composition of kingpins is even more complex. The carefully controlled metallurgical composition of kingpins is designed to maximize the same properties, but the reality is that manufacturers of fifth wheels and kingpins are limited. They must balance the hardness, strength, wear, and corrosion resistance properties of the metal. Unfortunately, you just cannot have it all. 

Wear is Unavoidable but Manageable

Commercial trucks and trailers, by the very nature of the work they do, require that they regularly connect and disconnect. It is not uncommon in a food service or freight delivery fleet to have a semi-truck connect and disconnect multiple times a day. 

This results in wear and damage which is unavoidable. The question then becomes, how do fleets manage this wear and damage and reduce the cost of replacing damaged fifth wheels and kingpins? 

By reducing the variances across the fleet and keeping all equipment within the manufacturer’s operational specifications, you can curb excessive wear and prolong the connection components lifespan.

Stop the Cycle of Wear and Damage

At Kingpin Specialists the first step is always a fleet inspection. It is very important to identify and repair the kingpins that are worn beyond operating specifications or are damaged. Worn or damaged kingpins can continue to damage every fifth wheel that they come in contact with. The same applies to fifth wheels. If a fifth wheel is not properly adjusted and maintained, they can cause excessive wear and damage to the kingpin during connection and use.

Once the fleet inspection has been completed the targeted kingpins are scheduled for repair. At Kingpin Specialists we have the capacity to repair a single unit or schedule multiple trailers to be repaired at one time. This allows us to repair them with the least amount of downtime possible. On large projects we often schedule repairs on weekends to limit the impact of daily operations and equipment needs.

Maintain Proper Records and Monitor the Situation

It is very important to maintain good records and Kingpin Specialists stamps every refurbished kingpin with a unique identification number. The trailer is tagged with our certified refurbishment label in an easy to see location for quick identification.

Once all the worn and damaged kingpins have been repaired, our service does not end. We continue to monitor the wear throughout the lifespan of the equipment. By continuing yearly checks and service, we can identify anomalies and project upcoming repair needs. More trained and experienced eyes on the most critical point of connection, reduces the chance of missing something that can lead to unnecessary repair costs and even possible catastrophic failure. With our proactive approach and connection management service, we identify issues before they become a problem and save our clients excessive repair cost. More importantly, our approach reduces unexpected equipment downtime.  

We Provide Nationwide Service

If you would like to take the first step and have Kingpin Specialists perform an inspection call us at 1-888-221-7774 or email us at

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