The Roto-Joints are smooth. Now that I have most of the bad movement gone from the welding it is noticably smoother. I think that once I get these new uppers installed it will make more of a difference. The other benefit is no binding at all.
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- Thread starter 1971Chevelle
- Start date
The Roto-Joints are smooth. Now that I have most of the bad movement gone from the welding it is noticably smoother. I think that once I get these new uppers installed it will make more of a difference. The other benefit is no binding at all.
So you have them Upper & Lower? Maybe I misunderstood?
My lowers are UMI with the Roto-Joints at both ends. My current uppers have heim joints, but the differential housing has the Roto-Joints installed. These new uppers will give me Roto-Joints at all positions in the rear.
Does doing this make a better cornering ride? or ? Edit I see you Daily Drive your Chevelle so I trust your judgement
Derek69SS
Veteran Member
The rear suspension was designed with rubber bushings that twist and flex in all directions, but also too soft for performance because they allow the axle to move a lot. (pinion angle change on accell/decell and lateral movement in cornering)
Poly bushings eliminate the movement, but also create bind because the upper arms movement relies on rotation on multiple axis, but the bushings only allow 1 axis of rotation.
Roto-Joints are the best of all worlds. Rigid enough to keep the pinion angle and lateral location from moving, and multi-axis swivel that eliminates all of the binding.
Lowers don't bind nearly as much as the uppers, so if you're going to only do rotos in one place, do the uppers.
Poly bushings eliminate the movement, but also create bind because the upper arms movement relies on rotation on multiple axis, but the bushings only allow 1 axis of rotation.
Roto-Joints are the best of all worlds. Rigid enough to keep the pinion angle and lateral location from moving, and multi-axis swivel that eliminates all of the binding.
Lowers don't bind nearly as much as the uppers, so if you're going to only do rotos in one place, do the uppers.
I got the new trailing arms installed this morning, & took a couple of pictures where the repair was done. You can clearly see in the one photo that it was elongating the holes on both sides. I also took a picture of one of the UMI arms next to one that I had in there. You can see that the ones I had were pretty dang beefy. I think I will order some Roto-Joints down the road and install them on the old arms to have as spares. Mine have left hand threads at the heim joint end. And, yes, the UMI arms were already scratched when I took them out of the box (they don't put any padding in them at the factory).
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Looks good. I also have UMI arms on my rear end.
I just took it for a drive for the first time with the new uppers. All I can say is that it is very smooth, and that it feels much more connected. Oh, and no more clunking noises when accelerating or pulling into driveways. Now if I can just figure out how to get rid of the front end shudder when I hit bumps in the road, all will be well.
Viking double adjustable coilovers set to a street setting. UMI upper and lower control arms.
kmakar
Janitor
Check for play in everything?
Not really in the mood to put it up on jack stands again. When it was in the air the last time, I didn't notice anything out of whack.
kmakar
Janitor
Anyone you know nearby have a lift?
Nope.
kmakar
Janitor
Next best thing you can do is to bring your car in for an alignment to a shop that is a bit lenient on allowing people in the shop and both you and the tech inspect. A second set of eyes might be a good idea.
I can get a free alignment check and they will bring you into the shop to show you any issues.
kmakar
Janitor
There you go, free is even better.