Tech Article: TeraFlex Tie Rod and Drag Link

Written by TeraFlex Engineering Technician -

Mike Owens





Engineer Mike Owens

 

When I first started out on our new HD Steering project, TeraFlex saw a need to provide the market with a premium option that was truly heavy duty in every aspect, including the joints used. Not only did the steering need to be loaded with the best features available and nearly indestructible, it needed to be an amazing value, and offer that “Best Bang for Your Buck”. Because our entire engineering department, myself included, all love Jeeping and have a passion for modifying our jeeps with parts that go above and beyond against the abuse not only off-road, but on-road as well (you only have to drive on Utah freeways once to understand this), we wanted a solution. I think our new HD steering meets the demand.

 

Many of you probably already knew that we designed our new HD Chromoly Tie rod with Forged ends and Forged Drag Link specifically for the Jeep Wrangler JK. But what about the Joints that we use in these new steering components? What makes them so special and the best choice for every Jeep JK enthusiast looking for a truly impressive Heavy Duty steering? I want to give you a small glimpse through my eyes as I went through the design process for these joints.

 

First, if you haven’t checked out our Premium HD Ball Joints yet, this video will give you an explicit insider view of what is really happening in our new ball joints, specifically the lower ball joint. I personally spent a lot of time researching and fine tuning the lower ball joint design. It is the joint that solely carries the weight of the Jeep, so it needed to be robust and ready to take a beating. Our new steering joint follows this same design and offers all the benefits of our Premium HD Lower Ball Joints. Benefits include a huge 1-1/8” diameter ball stud for maximum contact and wear surface made from heat treated 4140 Chomoly, premium tool steel wear plates, easy greasing and the ability to adjust out any play that may develop over a lifetime of hard abuse on the trails. What is there not to love!? Our steering joint has one more unique feature that really sets it apart from the rest though.

 

The JK has a different tie rod than most typical applications. You'll notice that instead of being a straight rod, it is offset from the axis between the two tie rod ends or joints, bent out away from the axle in order to clear the differential cover and the trackbar frame mount at full suspension compression. This offset shape causes the tie rod to be able to rotate up and down on the Jeep, which can be undesirable if not controlled properly.  A small amount of rotation is needed as you turn left to right because the angle of your axle outer knuckles will differ from one another, requiring misalignment of the joints which are provided by that slight rotation. If there is no rotation available at all from a tie rod, it will cause severe binding in the steering when you turn. On the other hand, if the rotation or misalignment is not controlled, this will cause your tie rod to “flop” around while driving and when steering loads are applied. This is where the TeraFlex Steering Joint comes into play to resolve this problem. Our new design involves using a unique stud opening profile in our forged and heat treated joint housing which I'll call a “channel” profile, shaped like a wide rectangular slot or channel instead of your typical round opening.  This new shape allows an impressive 60° of movement (30° each way) for drag link applications, which I'll discuss in a moment, and when turned 90° the joint is limited to a steady consistent 14° (7° each way), which is the bare minimum required for the max steering angle of your Jeep JK. This keeps your tie rod and drag link rotation smooth and controlled, offering precise and exact steering movements.


The 60° provided by the channel profile design is for when the ball joint is used in the drag link application, not so much the tie rod. The drag link is the bar that goes from the steering box on the frame, to the axle, that actually makes the wheels turn side to side. Because it is connected between the frame and the axle, it is constantly moving up and down when the suspension is compressing and drooping off-road, so the joints need to have lots of available movement for Jeeps with long shocks and lots of wheel travel.


Make sure to research all the details when looking at new Heavy Duty steering replacement options for your JK. This is only one of many features built in to our new HD Steering Components to give YOU the TeraFlex Advantage.

 
















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