Welcome!
My understanding is that a bushing in this context is designed to stretch and deflect from misalignment, where a flex joint is a ball and socket type connection.
Yeah, I don't disagree that its a bushing. Its just interesting that Metal Cloak calls theirs a FlexJoint and Synergy calls it a bushing. They perform in a very similar manor. Maybe because the Metalcloak has a ball encased in that rubber somewhere. I just found it interesting that they used different terminology for something very similar. That was all.
The simple reason Synergy cannot use their DDB on the frame side of the front track bar is the very same reason Metalcloak cannot use their Duroflex bushing. Neither bushing can be held in a permanent state of misalignment. This is one fundamental difference between a bushing and the ball and socket type connection we call a flex joint.
I understand this. I was just pointing out that Synergy, like Currie, uses their own existing product where its appropriate. Unlike MetalCloak that created a new product for that axle location. Begging the question of why Metalcloak didn't use the same bushing there. I actually prefer that Synergy uses the factory style ball joint at the frame. I'd rather not drill out that tapered hole.
On the Synergy rear track bar, the frame side looks like a traditional heim joint. As with Metalcloak, it would be interesting to know why Synergy is not using their bushing on both sides of the rear bar. OEM does. Currie uses a Johnny Joint on both ends of theirs.
That is exactly what I was wondering too.
The Synergy DDB looks like a more complex competitor to the Duroflex bushing. I personally do not see what real world problem either is solving that isn't already done better than the Johnny Joint.
That really is the question of the thread isn't it? Is it NVH? Durability (of the joint and other components). Maintenance free?
Something else to consider... Why does Mopar use a Dual Durometer Bushing in their 2" lift kit for the new Wrangler JL? OME also chose a DDB bushing for their control arms.
http://arbusa.com/Uploads/PDF/newProductAdvice/2016/ARBJKControlArms_Retail.pdf What did Jeep and OME see in the DDB bushing that they chose to use a DDB instead of Clevite or a JJ.
I'm not arguing the JJ is a bad joint. I'm saying its not perfect. There are trade offs. I have a hard time seeing how a JJ wouldn't transmit more NVH. It uses less material to cushion the vibrations and impacts. It has to transmit more NVH. Its physics. The bigger question might be how much less NVH does Clevite, Duroflex, or DDB transmit. And is it signficant enough to matter. What are the tradeoffs?
"Undamped" Heim joints and "limited damped" Johnny Joints have been on the road in many applications including daily driven vehicles for years. Are there real world examples where a mount failed because of these micro vibrations? The examples I have seen are typically the result of a the joint or bushing having insufficient misalignment capabilities.
OEM applications? Or are you referring to aftermarket joints. Are there any examples of Johnny Joints being used by OEM in control arm type of joints? I don't meant this to be an insult phrase. I genuinely don't know.
I understand that OEM manufactures have different priorities than the offroad/enthusiast crowd. Maybe they choose Clevite over JJ simply because its cheaper, maintenance free, and will outlast the warranty. It might be that simple. But then why use DDB instead of a JJ in your performance division that doesn't have the same restrictions? Is it an NVH thing or something else?
I really wish we had a way to reliably test the NVH of a JJ, DDB, Duroflex, and Clevite bushing. How much vibration is transmitted through each joint? How much impact is transmitted through the control arm directly to its mount in a high impact event like hitting a pothole. Obviously the tire doesn't absorb it all. I can feel it hit from the drivers seat.
If a jeep is traveling down the Interstate at 80mph and hits a 6" deep pothole, how much force is transmitted back to the mounting bracket. For those of us who have to drive our Jeeps 1000+ miles across the country just to get to the trailhead, these are real issues. Its not just a matter of some annoying NVH. What happens at highway speeds?
To sum up a rather long post. What is the impact of NVH on the mounting brackets and hardware over long term periods in harsh conditions. How much vibration and stress does it take for metal to fatigue? Can a control arm hitting a pothole at 80mph produce enough force to rip a mounting bracket loose? What if that mounting bracket has suffered metal fatigue over thousands of miles?
