UMI Roto-joints Rear LCA
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Joined: Feb 2012
Posts: 189
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From: Tokyo, Japan
Car: 92 camaro convertible z28
Engine: 305 TPI
Transmission: Swapped from 700R4 to T5
Axle/Gears: Stock Posi. Ratio is not known
UMI Roto-joints Rear LCA
Now, poly-poly LCAs are in my rear, but I'm planning to change them to UMI's roto-roto LCAs.
My car is complete for street use, and I don't like harsh ride.
How good roto-joints are for street use?
Are they harsher than poly-poly LCAs?
My car is complete for street use, and I don't like harsh ride.
How good roto-joints are for street use?
Are they harsher than poly-poly LCAs?
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Joined: Sep 2006
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From: Houston, TX
Car: 1989 GTA
Engine: SuperRam 350
Transmission: Pro Built S/S TH700R4
Axle/Gears: 3.27
Re: UMI Roto-joints Rear LCA
When I went from rubber to Spohn Del-sphere (both sides), I didn't notice ANY increase in ride stiffness. The car did feel tighter. But not any stiffer riding at all.
Del-Sphere and Roto-Joint are basically the same thing.
Del-Sphere and Roto-Joint are basically the same thing.
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Member

Joined: Feb 2012
Posts: 189
Likes: 2
From: Tokyo, Japan
Car: 92 camaro convertible z28
Engine: 305 TPI
Transmission: Swapped from 700R4 to T5
Axle/Gears: Stock Posi. Ratio is not known
Re: UMI Roto-joints Rear LCA
Thanks.
How are the noise and vibration?
No difference?
UMI also prepares poly-roto LCAs, so I suspect there must be some downside of roto-roto LCAs...
How are the noise and vibration?
No difference?
UMI also prepares poly-roto LCAs, so I suspect there must be some downside of roto-roto LCAs...
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Joined: Sep 2006
Posts: 2,118
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From: Houston, TX
Car: 1989 GTA
Engine: SuperRam 350
Transmission: Pro Built S/S TH700R4
Axle/Gears: 3.27
Re: UMI Roto-joints Rear LCA
None. Absolutely zero...... My city is all concrete roads with way too many potholes, cracks, and bumps. And I live near the center of the city. So it's not like I live way out of town on rarely traveled roads.
I owned the LCA and PHB for quite some time before putting them in. Precisely because I was worried it would ride too hard afterwords. But I gave up nothing for the increase in performance.
I'm not sure that poly would even ride any smoother. Poly doesn't have any movement. Roto-joints can rotate when they need to.
I owned the LCA and PHB for quite some time before putting them in. Precisely because I was worried it would ride too hard afterwords. But I gave up nothing for the increase in performance.
I'm not sure that poly would even ride any smoother. Poly doesn't have any movement. Roto-joints can rotate when they need to.
Thread Starter
Member

Joined: Feb 2012
Posts: 189
Likes: 2
From: Tokyo, Japan
Car: 92 camaro convertible z28
Engine: 305 TPI
Transmission: Swapped from 700R4 to T5
Axle/Gears: Stock Posi. Ratio is not known
Re: UMI Roto-joints Rear LCA
Thanks for your info.
Now I've decided to go for roto-roto.
I think roto-roto ones are ideal because both sides of LCAs should have free movement to prevent bind completely.
Now I've decided to go for roto-roto.
I think roto-roto ones are ideal because both sides of LCAs should have free movement to prevent bind completely.
Thread Starter
Member

Joined: Feb 2012
Posts: 189
Likes: 2
From: Tokyo, Japan
Car: 92 camaro convertible z28
Engine: 305 TPI
Transmission: Swapped from 700R4 to T5
Axle/Gears: Stock Posi. Ratio is not known
Re: UMI Roto-joints Rear LCA
Btw, how about the maintenance cycle of roto joints?
Did you retighten them? If so, how long until retightening?
Did you retighten them? If so, how long until retightening?
Joined: Sep 2004
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From: Chicagoland Suburbs
Car: 1989 Trans Am GTA
Engine: LT1, AFR 195cc, 231/239 LE cam.
Transmission: M28 T56
Axle/Gears: 3.23 10bolt waiting to explode.
Re: UMI Roto-joints Rear LCA
However, they come with greasable fittings, so you should grease them once in a while.
The Delrin part does wear out, but then you just need the wrench and you can tighten them again.
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Re: UMI Roto-joints Rear LCA
Hey guys.
Our intention with poly-roto vs roto-roto is to have the poly be potentially a little "softer" but if dual roto doesn't pose any problems in real world conditions that's a pretty nice testimonial.
We've seen street cars go a few seasons with no roto adjustment required where others (maybe with lots of abuse) need a quarter turn every so often. The Roto-Joint really is a cool piece and works well.
Maintenance is usually a few pumps of grease a few times per season.
If they do wear out, the Delrin pieces are $6 per end ($3 each side of the ball). As an example I get about one call per month, maybe less, with guys buying them.
Let me know if you have any questions.
thanks
ramey
Our intention with poly-roto vs roto-roto is to have the poly be potentially a little "softer" but if dual roto doesn't pose any problems in real world conditions that's a pretty nice testimonial.
We've seen street cars go a few seasons with no roto adjustment required where others (maybe with lots of abuse) need a quarter turn every so often. The Roto-Joint really is a cool piece and works well.
Maintenance is usually a few pumps of grease a few times per season.
If they do wear out, the Delrin pieces are $6 per end ($3 each side of the ball). As an example I get about one call per month, maybe less, with guys buying them.
Let me know if you have any questions.
thanks
ramey
Thread Starter
Member

Joined: Feb 2012
Posts: 189
Likes: 2
From: Tokyo, Japan
Car: 92 camaro convertible z28
Engine: 305 TPI
Transmission: Swapped from 700R4 to T5
Axle/Gears: Stock Posi. Ratio is not known
Re: UMI Roto-joints Rear LCA
Hey guys.
Our intention with poly-roto vs roto-roto is to have the poly be potentially a little "softer" but if dual roto doesn't pose any problems in real world conditions that's a pretty nice testimonial.
We've seen street cars go a few seasons with no roto adjustment required where others (maybe with lots of abuse) need a quarter turn every so often. The Roto-Joint really is a cool piece and works well.
Maintenance is usually a few pumps of grease a few times per season.
If they do wear out, the Delrin pieces are $6 per end ($3 each side of the ball). As an example I get about one call per month, maybe less, with guys buying them.
Let me know if you have any questions.
thanks
ramey
Our intention with poly-roto vs roto-roto is to have the poly be potentially a little "softer" but if dual roto doesn't pose any problems in real world conditions that's a pretty nice testimonial.
We've seen street cars go a few seasons with no roto adjustment required where others (maybe with lots of abuse) need a quarter turn every so often. The Roto-Joint really is a cool piece and works well.
Maintenance is usually a few pumps of grease a few times per season.
If they do wear out, the Delrin pieces are $6 per end ($3 each side of the ball). As an example I get about one call per month, maybe less, with guys buying them.
Let me know if you have any questions.
thanks
ramey
Thanks for the reply Ramey.
Just one question: How can you tell if adjustment of roto joints is needed?
Cluttering noise or something?
Or take them apart anyway and see if there is any play?
Re: UMI Roto-joints Rear LCA
If adjustment is required, you will see some play during servicing. Or if you lift with a floor jack you can see movement. Some Roto-Joint arms last many many years before needing tightened.
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