Rear lower control arms

[383_GrandPrix]

So I recently finished going through and painting the rear axle I got for the Grand Prix. It's an 8.5 10 bolt with a posi and 4.10 gears that supposedly came from a 75 Monte Carlo. I just ordered a set of UMI 12 bolt swap uppers with the Roto-Joints and I'm looking forward to receiving those. So now I'm looking to the next logical upgrade, lower control arms. Since I invested in the adjustable control arms with Roto-Joints for the uppers, I figure why not use them for the lowers as well. I went looking on the UMI website for their lower control arm options and found their only listing for adjustable with Roto-Joints is $380+ add-on's . So I did some digging to see what else was on the market, and found that SPOHN offers a similar product for $250+ add-on's.

http://umiperformance.com/catalog/index.php?main_page=product_info&cPath=8_60_70&products_id=379

https://www.spohn.net/shop/1978-198...-Adjustable-with-Del-Sphere-Pivot-Joints.html

The only real differences between the two are;
The UMI arms use 1.500" DOM mild steel tubing and 4140 thread tube adaptors with their Roto-Joint ends.
The SPOHN arms use 1.250" DOM mild steel tubing and 4130N thread tube adaptors with their Del-Sphere ends. Or for an extra $30 they will make the whole thing out of 4130N.

So I'm wondering if any one has ever used any of spohn's products in the past who can vouch for their stuff? Or does anyone know if the difference is worth the extra $100?

 

[pontiacgp]

what about these ones and asking them to switch out the rod ends for the Rotojoint.

http://umiperformance.com/catalog/index.php?main_page=product_info&cPath=8_60_70&products_id=86

When I ordered mine UMI didn't have any rod ends or Rotojoints on the lower control arms. The did a modification for me and cut one end off and tapped it for the Rotojoint. They just added the cost for the Rotojoint to the cost and threw in the labor to modify it. I needed the Rotojoint for my 8.2 rear end.

 

[383_GrandPrix]

I did think of that as well, I wonder how much extra they would charge for that? spohn already has a product listed like that though;
https://www.spohn.net/shop/1978-198...e-with-Poly-Del-Sphere-Pivot-Joint-Combo.html

 

[pontiacgp]

You might also want to contact this guy, he can get the UMI parts cheaper with less shipping costs. He got me the parts just a little higher than what UMI was charging even with the exchange.

http://www.powerhouseperformance.ca/index.php?main_page=index&manufacturers_id=85

 

[383_GrandPrix]

You might also want to contact this guy, he can get the UMI parts cheaper with less shipping costs. He got me the parts just a little higher than what UMI was charging even with the exchange.

http://www.powerhouseperformance.ca/index.php?main_page=index&manufacturers_id=85

My father is a long haul truck driver and drives past Lane Automotive on a fairly regular basis so I get most of my stuff through them so I don't have to deal with shipping; but that's good to know, thanks for the info!

 

[64nailhead]

We are using the ones pontiacgp linked on our 8.5. They work fine, but our car is street driven ALOT. I think the rotorjoint unit is for more of a full race unit, and that is road race. Keeping rubber in one of the joints eliminates most of the banging/clunking during normal driving.

Don't forget to budget in for a sway bar. We put in the UMI bar and it was night and day in terms of body lean.

 

[383_GrandPrix]

We are using the ones pontiacgp linked on our 8.5. They work fine, but our car is street driven ALOT. I think the rotorjoint unit is for more of a full race unit, and that is road race. Keeping rubber in one of the joints eliminates most of the banging/clunking during normal driving.

Don't forget to budget in for a sway bar. We put in the UMI bar and it was night and day in terms of body lean.

UMI created their Roto Joints as a more street friendly option then heim joints. I don't want to use heim joints if I can avoid it as my car will be mostely street driven, only seeing some track use and don't want a lot of NVH.

 

[pontiacgp]

UMI created their Roto Joints as a more street friendly option then heim joints. I don't want to use heim joints if I can avoid it as my car will be mostely street driven, only seeing some track use and don't want a lot of NVH.

I've had the Roto joints on the conversion uppers and lowers for the last 3 summers, I grease them in the spring and they have not shown any wear. My GP is my daily driver in between the winters and I don't drive it too gently so I am happy with those joints

 

[383_GrandPrix]

So I messaged UMI and they said that they could make those arms and just replace the heim joint with a Roto Joint. But because the Roto Joint is bigger, it would only be able to go from stock length to longer, not shorter. So I asked them if this set will mount up;
http://umiperformance.com/catalog/index.php?main_page=product_info&cPath=7_138_101&products_id=393

They said yes, as long as I don't plan on using the factory mounted sway bar. That doesn't matter to me as I will be copying Pontiacgp and modifying an F body sway bar.

 

[383_GrandPrix]

I've had the Roto joints on the conversion uppers and lowers for the last 3 summers, I grease them in the spring and they have not shown any wear. My GP is my daily driver in between the winters and I don't drive it too gently so I am happy with those joints

I've heard a lot of good things about them, that's why I made the investment. I have no doubt that I will be happy with them.