New Upper Coupler Isn't Always Better

Why a New Upper Coupler Assembly Isn’t Always Better

Fleets usually don’t realize there is an issue with their kingpins and upper coupler assemblies until something breaks. When that happens, your first instinct may be to replace the entire assembly with a new upper coupler.

We have seen too many fleets follow this path even though replacing the upper coupler may not be the most cost-effective option. Let’s dive into why a new upper coupler assembly isn’t always better.

OEM Replacement Bolster Plates Aren’t Up to Spec

You may think that purchasing a replacement bolster plate from the original equipment manufacturer will give you the same quality and longevity as new. This isn’t always the case.

Many OEMs will send a thinner plate than the one installed in the factory. These plates aren’t as strong or long-lasting as the original bolster plate. While a new trailer’s bolster plate may have an expected lifespan of 10-15 years, a thinner replacement’s lifespan could be significantly less. If your fleet operates in the northern states where calcium chloride road salt is used in the winter, this wear will accelerate even more.

Semi-truck and trailer driving in winter conditions accelerate wear on the upper coupler.

If OEM replacements aren’t going to work, what about aftermarket replacements? There are so many manufacturers and variables in the aftermarket that finding a good replacement might be difficult. Aftermarket bolster plates could be too thin or even too thick, with unknown performance expectations. There isn’t a standard thickness or strength that aftermarket manufacturers must stick to, so you really don’t know what you’re getting with an aftermarket bolster plate.

These days, fleets need to keep their equipment in good condition for longer, but unfortunately swapping bolster plates just won’t do the job.

Custom Fabricated Assemblies Lack Standards

If replacement bolster plates are off the table, what about custom fabricated upper coupler assemblies?

When an original equipment manufacturer is making a new assembly, the components go through testing to ensure the assembly will meet strength and structural standards. An average repair shop doesn’t have a certified engineer on staff to ensure a custom fabricated assembly meets these same standards.

A repair technician or welder may be able to weld up an upper coupler assembly, but may not have the skill set or testing methods to ensure that the assembly will perform the same as OEM. Unfortunately for fleets who take this route, they may spend thousands of dollars per trailer only to have the assembly fail after just a few months.

Not all welders can ensure the assembly will meet OEM specs.

Cutting In a Kingpin Compromises Structural Integrity

Replacement bolster plates and customer fabricated assemblies are often too costly while not solving ongoing maintenance issues like excessive wear. What about removing just the damaged kingpin and cutting in a new one?

Purchasing a replacement kingpin is a gamble. Kingpins manufactured in North America need to meet strength standards, but those manufactured overseas can be made from subpar material. While they may be less expensive, an overseas kingpin may not last.

The process of replacing a kingpin can compromise the structural integrity of the upper coupler. Cutting into the framing assembly when installing a replacement kingpin creates a weak point that, if not properly reinstalled, could easily break under stress. We’ve seen many cut-in kingpins break free due to improper welds and even break through the bolster place. Unfortunately, this typically results in a catastrophic failure and a disconnected trailer.

The risk of losing a trailer or even putting lives at risk is too high for any fleet.

Remanufacturing Is the Answer!

Now that you know more about replacement bolster plates, custom fabricated assemblies, and cut-in kingpin replacements, you may agree that there aren’t always the best options. So how should you handle the wear on your kingpins?

Kingpin Specialists uses an engineered remanufacturing process that is a non-invasive repair option. We repair the kingpin on the original assembly without altering the structural integrity. Our certified kingpin remanufacturing welders fill in the wear on a damaged kingpin and machine it down to the original manufacturer’s operational specifications.

This process leaves your bolster plate intact, and your trailer with a kingpin that will perform like new. We back our work with a 100% guarantee that our remanufactured kingpins will operate and wear just like the original.

Certified welder restoring a kingpin to OEM specs.

If the upper coupler is structurally sound and the bolster plate does not have significant wear, remanufacturing is one of the most cost-effective ways to address your fleet’s maintenance needs. Additionally, the remanufacturing process allows for repairs to be completed proactively. This can eliminate downtime and ensures the equipment is operating within the manufacturer’s safety standards.

We provide free fleet evaluations for fleets across the U.S. and Canada. Our technicians will come to you and take measurements to see if there is damage or wear on your trailers’ kingpins. If there is, we can send you a report and create a customized plan to bring your wear rate down and make your equipment last longer.

Time to Call the Kingpin Specialists

If you operate commercial trailers, you have had a difficult couple of years because of the impact of the pandemic. We don’t want to see things get worse for you because a kingpin that is damaged or has excessive wear leads to a compliance or safety issue.

Kingpin Specialists provides an engineered kingpin repair solution performed by certified welders who have been specifically trained with Kingpin Specialists’ industry-leading process. When Kingpin Specialists is done with your trailers, you will be done with excessive wear and damage to your kingpins and fifth wheels.

Without understanding the scope of the connection management issues affecting a fleet, it is impossible to quantify the real long-term costs. It is also difficult to make any meaningful progress in fixing the ongoing connection management issues.

Most in-house technicians do not have an engineered solution at their disposal, lack the experience and training required to repair kingpins effectively, and even misunderstand the relationship between the fifth wheel and kingpin.

If you are responsible for fleet maintenance on commercial vehicles, why not take the first step and have Kingpin Specialists perform an inspection and report on the condition of your fleet?

Call us at 1-888-221-7774 or email us at

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