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Does control arm bushing composition affect ride quality or NVH?

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bobthetj03

bobthetj03

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Post #281
So, let me see if I have this,

You have synergy front uppers with Currie jj's on the front axle (Currie axle kit I assume).
Synergy front lowers. Synergy rear uppers, and stock rear lowers?
 

Fargo

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Thanks for posting your thoughts. I'm still bummed that Synergy doesn't make the front upper bushings anymore. But I will likely go with the JJ kit like you did there as well.

So did Bobthetj03 get your setup correct? That is how I read it too. If so, why did you go with the Moog rear lowers when everything else was Synergy.
 
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Fargo

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Close enough to count?
I think both companies had similar goals in mind, but they took very different approaches. If you look into the two products you will see they are quite different. Synergy uses a dual durometer press in bushing so it is maintenance free. It then uses a teflon liner to allow free rotation within the bushing. Metalcloak uses only a single durometer of rubber and rotates within the housing and requires some periodic maintenance to ensure it rotates freely. So similar but yet very different.
 

k-huevo

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Thanks for posting your thoughts...why did you go with the Moog rear lowers when everything else was Synergy.
You're welcome.

The Moog LCAs were very inexpensive. It's possible I'll change to adjustable LCAs in the future, but for now I only needed to rotate the pinion down a bit, and remove rear UCA bind.

I like JJs, and I think Synergy's bushing is a good companion in a CA application. Both have 30 degrees of misalignment capability, and the DDB returns to center, which appeals to the side of me that likes things tidy. Maybe I'll be able to use hybrid adjustable CAs when the time comes. The shop where I had the passenger side axle mount work done, pairs JJ & DDB control arm ends on some builds.
 
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bobthetj03

bobthetj03

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You're welcome.

The Moog LCAs were very inexpensive. It's possible I'll change to adjustable LCAs in the future, but for now I only needed to rotate the pinion down a bit, and remove rear UCA bind.

I like JJs, and I think Synergy's bushing is a good companion in a CA application. Both have 30 degrees of misalignment capability, and the DDB returns to center, which appeals to the side of me that likes things tidy. Maybe I'll be able to use hybrid adjustable CAs when the time comes. The shop where I had the passenger side axle mount work done, pairs JJ & DDB control arm ends on some builds.
Wouldn't you be concerned about the jj's putting additional strain on the Synergy joints? jj's don't return to center, so they could potentially leave the Synergy joint in a constant state of misalignment, thus creating potential premature wear. Now, if the Synergy joint has enough muscle to bring the jj's back in line, I guess it would be doable. Just a thought. I could be way off base.
 

Fargo

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Wouldn't you be concerned about the jj's putting additional strain on the Synergy joints? jj's don't return to center, so they could potentially leave the Synergy joint in a constant state of misalignment, thus creating potential premature wear. Now, if the Synergy joint has enough muscle to bring the jj's back in line, I guess it would be doable. Just a thought. I could be way off base.
Wasn't this the issue MetalCloak was talking about to sell more arms? I don't really follow this. If your Jeep is siting on level ground, how much movement is their in your arms? My stock arms are pretty much fixed in place. I don't see how putting a JJ on one end is going to suddenly put the arm in a different position. It seems to me the misalignment is pretty much set by where the brackets are mounted. Am I missing something?

EDIT: I don't think Synergy takes any position on this issue.
 
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bobthetj03

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Wasn't this the issue MetalCloak was talking about to sell more arms? I don't really follow this. If your Jeep is siting on level ground, how much movement is their in your arms? My stock arms are pretty much fixed in place. I don't see how putting a JJ on one end is going to suddenly put the arm in a different position. It seems to me the misalignment is pretty much set by where the brackets are mounted. Am I missing something?

EDIT: I don't think Synergy takes any position on this issue.
Yes, that was the issue with the Duroflex joints and using a jj at the other end. the durometer is just too soft to allow any fight back of a jj when misaligned. Like I said, I could be way off base here. I used to run Currie arms up front, and a jj will be where it wants to be. As an example, notice my driver side lower arm and where the jj is misaligned at. that is sitting in a level parking lot at work during a normal commute to work.
100_0629.JPG

I've had those Currie arms on a bench vise before, and I can tell you it takes some effort to misalign a jj. Having a different joint at the other end that wants to self center would take said joint some muscle to bring the jj back to its center, IMO. Is a Synergy joint up to the task?
 

jjvw

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Wasn't this the issue MetalCloak was talking about to sell more arms? I don't really follow this. If your Jeep is siting on level ground, how much movement is their in your arms? My stock arms are pretty much fixed in place. I don't see how putting a JJ on one end is going to suddenly put the arm in a different position. It seems to me the misalignment is pretty much set by where the brackets are mounted. Am I missing something?

EDIT: I don't think Synergy takes any position on this issue.
Arms with a spherical end on both sides will wander within the bracket as the suspension moves. It is what it is and does not matter. A hybrid arm will now want to keep its bushing in it's neutral position. Meaning that the less resistant end of the arm will do the majority of the movement where possible. Does that matter? I suppose it depends on the joints and bushings being used on the arm.
 
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Fargo

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Bobthetj03. Thanks for the picture. I see what you guys are talking about and I now understand what you are saying. It does seem like that could put extra stress on the DDB.

I also didn't realize the JJ fit that tight in the socket. I thought it spun easily by hand. So I wonder then if you would be better off using Clevite or even Metalcloak on the upper axle mounts.

k-huevo - can you tell us how your upper arms look after you flex them? Does the DDB bring them back to alignment.
 
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k-huevo

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The joint ends are centered after flexing. During flex the JJ moves further first, then the DDB joint follows, when the JJ reaches its limit, the DDB moves a bit more. This image is on the previous page, and it is a bit blurry, but it shows both ends centered at ride height.
IMG_1694.JPG

One advantage of Synergy's single side telescoping adjuster is once centered, the pinch bolt is tightened, which does not effect either end's angle.

Speaking of MC, they also have front axle replacement bushings, and state emphatically they are only compatible with MC arms.
 

Fargo

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Thanks. So it would seem that the DDB is strong enough to center the JJ. I suppose that might impose some additional wear vs having a DDB on both ends sharing the load. But once it has done the work of returning to center it should be the same... RIght?

That puts me back in the camp of doing the JJ on front top arm like you did.
 
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bobthetj03

bobthetj03

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It appears the Synergy joint is up to the task of keeping the jj in line. Good to know. Too bad Synergy no longer makes the axle side joints. No way would I attempt to do that with a Duroflex joint and a JJ. And now that MC has an axle side kit, there really isn't a reason for me to try since most of my arms are MC.
 

Blackjack

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So what bushings did synergy quit building part number wise?
4236-01 front axle upper bushing. You could use 4326-02 but will have to drill out for a larger bolt and figure out how you want to mount it on the passenger side. This is one spot where I am going to run JJs as they will be easier to service down the road.
 

k-huevo

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If you use a JJ bushing, be aware the TJ yoke will need to be drilled to 7/16" (12mm), or, a larger 1/2" cross-drilled JJ ball could be used, then drill the yoke holes to 1/2".
 

astjp2

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I am not a fan of any of the solid joints because of things like this, which is on a different post thread. That is why I am hoping the synergy bushings might be better than OEM with longevity. Tim

johnny joint.jpg