QA1 Rod Ends: Fasteners When Misalignment Is Required

Rod ends have been a part of race cars since the sport restarted after WWII. Suspension rods and steering rods have been adorned with these miracles of modern technology for over 70 years.

Today, when you hear the name QA1, most racers automatically think of shocks, springs, ball joints, and other suspension components. Truth be told, QA1 was founded on rod ends and have never strayed too far away from this foundation. Kaitlyn Nelson, QA1’s marketing manager, assured us they have the dirt track world’s needs covered with over 6,500 SKUs in rod ends, spherical bearings, custom linkages, and other related products. 

A rod end serves many vital functions in dirt track cars, from Factory stock to purpose-built Dirt Late Models and Sprint Cars. “A rod end is basically a fastener used when misalignment is required,” said Nelson. Dirt track applications where high misalignment is required due to the extreme wheel articulation is one area where we see a lot of use.”

Replacing rod ends is something nearly every circle track racer has to consider at some point, so the question becomes, “When do I replace my rod ends?” A quality rod end cost a little bit of money, so you don’t want to replace them every week. On cars with sophisticated race suspensions, it may take a lot of time to replace all the rod ends, so you don’t want to do it more often than you have to.

httpv://www.youtube.com/watch?time_continue=12&v=MbPQ5zDkons

What To Look For

QA1’s Scott Elmgren gave us some pointers on what to look for and the reasons behind the success or failure of rod ends on race cars. “A rod end should never limit the movement of a car’s suspension. If the rod ends come into bind and acts as a limiter, you can expect the rod end to bend or break over time,” he stated.

Pay attention to any suspension rod or component that binds or subjects the rod end to “over-traveling.” Most of the time, this is an unintentional consequence of a suspension system out-of-adjustment or a by-product of crash damage. Crashes can cause subtle changes in the frame and suspension that can cause rod end binding and shorten the lifespan of these bearings.

“Using the wrong diameter bolt through the ball, whether intentional or not, can shorten the lifespan of rod ends bearings,” added Elmgren. Obviously, if you want to extend the life of your rod ends, “don’t over-travel them, and use the proper sized bolts,” he added. “Using chemicals on the rod ends that react negatively with the rod end body, race, or ball bearing, can also dramatically shorten the life of a rod end.” Avoiding those chemicals is the solution to that specific problem. 

According to Elmgren, checking the rod ends can be done a couple of ways. “Ideally you would check the friction of the rod end dynamically, under a load. But this requires special equipment and is not feasible for most people,” he said. “Most will conduct a visual inspection and do a hand check to see how the rod end feels.” A worn rod end will be loose, but you don’t want one that is too tight and feels like it is binding either.

Which One To Use?

We couldn’t help but notice that QA1 offers five different lines of rod ends. Not one or two, but five! “We sell to many industries other than auto racing,” said Nelson. “Different industries such as construction, lawn and garden, marine, etc. require different materials and construction many times.” It makes sense that different industries may need different material grades due to the various load levels of the applications. Knowing that rod ends come in all these different styles, it would probably be wise for race car builders to match the rod end type with their intended use.

The selection process begins with choosing a company brand. “Racers should work with a company that not only provides a fair price, but a company that has a strict quality-control program,” says Nelson. “We recommend asking your rod end manufacturer what type of quality-control program they have, and if they are ISO certified.” QA1 prides themselves on sending every style of rod end, spherical bearing, and other linkage components through a stringent quality-inspection process. “If we get a batch of rod ends with improper material specs or if the dimensions aren’t perfect, we’re not afraid to scrap them and re-order from our supplier.” 

Nelson explained how to choose the right rod end for the application. “A lot of knowing what works best comes down to experience. We have people with 25-plus years of experience in the rod end industry and have numerous employees with a lot of racing and car building experience to work from. We strongly encourage the customer to call the QA1 Tech Line if in doubt.”

QA1 offers not just one, but five different styles of rod ends in various forms. From male to female threaded, to carbon steel or aluminum – every need is met.

The Basics

Rod ends are designed to take loads in radial and axial motion by virtue of a ball bearing mounted in the rod end’s housing. QA1 has five different styles of rod ends, each with a purpose in mind. Sometimes the names given to the different style of rod ends offer clues to their design. For instance, the two-piece rod end is made of two pieces; a ball and a body.

Two-Piece Rod End

QA1’s two-piece rod end, many times referred to as a Mohawk design, is an economy rod end. A no-frills rod end that features the body swaged around the ball on each side to lock it in, and then loosened. This style is generally very economical and is commonly used in light-duty applications. Very seldom used in race car applications.

QA1’s two-piece CF series, carbon-steel, female-threaded.

Three-Piece Rod End

This is where things get slightly more complicated. The three-piece rod end is made up of three separate parts; the ball, the body, and a sleeve. Here’s how it works: the ball is pressed into a sleeve that is swaged around the ball. After swaging, the unit is called the insert. The outside diameter of the insert is then machined-down and faced-off to square up the sides for staking into a rod end body.

A three-piece, HM series alloy-steel, male-threaded.

This style rod end offers better ball-to-race conformity for tighter tolerances. Many racers use these rod ends on radius rods, Panhard bars, lift-links, and other suspension components. Good choice for high-load, high-oscillation applications that require tighter tolerances.

Hardness testing at the factory.

The three-piece rod end comes in either the traditional metal-on-metal or with a PTFE liner. The PTFE lined rod end is self-lubricating and provides a lower coefficient of friction. These might not be major advantages in dirt track racing, but the advantage shows up as the liner prevents any space between the bearing and the housing. This prevents dirt or other contaminants from getting to the bearing surface. Metal-to-metal rod ends need lubrication which will attract dirt. Special care needs to be taken to keep metal-to-metal rod ends clean.    

Endura XF series, Chromoly-Steel, female-threaded.

Endura Series Rod End

Rod ends have been around since World War II when the Germans introduced them as part of aircraft construction. Over the course of decades, the basic design of rod ends changed very little until QA1 introduced their Endura Series in 1995. Officially referred to as Endura Loader Slot Series, these rod ends feature a body that is machined with a groove going all the way around the interior of the rod end body. The ball is placed in the machined groove, and a proprietary PTFE/Nylon material is injected that acts as a liner, a seal, and lubricating surface for the bearing. While keeping debris out of the rod end, the injected molding race provides added strength and longevity to the component.

Bronze Race Rod Ends

QA1’s V-Series rod ends feature a protective coating on the carbon steel body for corrosion-resistance in harsher conditions. Available in metric and SAE threads, in either male or female rod end styles, VF and VM are SAE thread in female and male versions respectively. All QA1 Bronze race rod ends come in right-hand or left-hand threads.

MVF and MVM are metric threaded in female and male versions. All feature a ball constructed out of 52100 bearing steel that is heat-treated and hard chrome-plated and precision ground. The sintered race is oil impregnated for lubrication. These rod ends are generally appropriate for low-load, high-oscillation applications.

Bronze MVF series, carbon-steel, female-threaded.

Injection Molded Rod Ends

Like most of the other rod ends offered by QA1, the injection molded rod ends feature a ball constructed from 52100 bearing steel that is heat-treated, hard chrome-plated, and precision ground with a body that is carbon-steel and protective-coated against corrosion. The difference with this rod end is the nylon (Nylon 12 with PFTE) self-lubricating, reinforced, race-compound.

Specifically designed to provide low-friction with low-moisture absorbing and high-wear resistance. Like the other QA1 rod ends, these are offered in left and right-hand thread versions. The injection-molded process allows the rod end to maintain full-strength and integrity because no holes need to be drilled into the rod end body. This style rod end is frequently seen on dirt tracks every weekend during race season.

NM series, injection-molded, carbon-steel, male-threaded.

In Closing …

Like with almost everything else in life, you don’t have to be an expert in every subject to have success. You don’t have to know everything, but it helps if you know where to go to get the information. As we mentioned above, component selection should start with a company that offers products at a fair price and has a tight quality-control program.

If you have any doubt or limited experience with rod end bearing selection, we encourage you to call QA1 or any distributor with a good tech line and work with them to find the product you need. For more information on the QA1 line of rod ends or other QA1 products, visit them online at www.qa1.net.

Article Sources

About the author

Bobby Kimbrough

Bobby grew up in the heart of Illinois, becoming an avid dirt track race fan which has developed into a life long passion. Taking a break from the Midwest dirt tracks to fight evil doers in the world, he completed a full 21 year career in the Marine Corps.
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