Spohn the only one for upgraded rear control arms?

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91RS

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I still haven’t found uppers. Here are the boxed lowers I am using. The only thing I want to do is tap them for grease zerks.


https://www.ebay.com/itm/272714638952



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Interesting. Not too expensive either but I don't think I would want poly bushings in one arm and not the other. I'd like them to be the same.
 

1BADI5

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I have the Spohn boxed LCA, great fit and finish.

BUT they can be noisy when going in and out of driveways and stuff. Where they're boxed, it eliminates some of the articulation that you have with the OEM LCA and rubber bushings. I still need to order the uppers at some point
 
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Emailed Spohn and they said they never made non-adjustable uppers but that they come adjusted to factory length so if you don’t want/need adjustment then just put them in as is.

Another thing that makes me think it may not be worth it is if I don’t have polyurethane bushings for the front, why bother with the rear?
 

iamdub

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Interesting. Not too expensive either but I don't think I would want poly bushings in one arm and not the other. I'd like them to be the same.

"Mismatched" bushings are actually beneficial and is common in dual sport setups. For example, those in Arizona, Nevada, etc. that play with their trucks in the desert on the weekends but also drive them to work in the city will use poly in the lower arms and Delrin in the uppers. Rubber is too soft and doesn't last in the dunes. Poly is much stronger, but still flexes some. Delrin is very stiff. Since most of the feel of the terrain is transmitted through the lower arms, they use poly to help absorb and smooth it out. Since the upper arms are more for control, Delrin is ideal.

The same applies for the rear of our rigs. Except, we can dial it back a notch and have rubber in the lowers and poly in the uppers. All the arms locate, control and transmit vibes. But, the lowers will do most of the absorbing and the uppers do more of keeping the axle from rotating. For my street rig, I'm keeping with rubber-bushed lowers. I'll use poly for the adjustable uppers since I already have the bushings on hand and I don't wanna research universal rubber bushings for sizes, etc. I'm only making adjustable uppers since I'm lowered (and going lower) and will be lengthening the lowers when I make them to set back and center the axle. I'll fine-tune the pinion angle with the uppers. Yes, I could determine the pinion angle and make longer, non-adjustable uppers to lock it in place, but I want adjustability just in case.
 
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This is just a daily driver. It has a mild cam, mild 2/3 drop, and will never be off-roaded or tracked. I was just looking at options for improvement on something I wanted to replace anyway. I’m not interested in fabricating custom suspension pieces or paying to have them made. The Spohn stuff is already pretty expensive compared to the OE parts.

Either way, if what you said is what is ideal for these trucks then using the eBay lower arms and stock upper arms is the opposite of ideal.
 
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iamdub

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This is just a daily driver. It has a mild cam, mild 2/3 drop, and will never be off-roaded or tracked. I was just looking at options for improvement on something I wanted to replace anyway. I’m not interested in fabricating custom suspension pieces or paying to have them made. The Spohn stuff is already pretty expensive compared to the OE parts.

Either way, if what you said is what is ideal for these trucks then using the eBay lower arms and stock upper arms is the opposite of ideal.

From a ride quality-vs-benefits perspective, yes, it is not ideal. You have nothing to gain with boxed lowers and poly bushings other than longevity of the bushings. I think that a 200K+ mile bushing life with the comfort of rubber bushings is very reasonable.
 

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I installed the Spohn lower boxed control arms in my rig.. I did it to help
deflection and tighten up the rear while towing.. I also did the bigger sway bars
front and rear. Everything is greaseable. So you have to make sure to do the
maintenance. I think it helped. For a "stockish" set up, just replacing the
the stock pieces is fine.. You'll get new bushings and that's what wears out
 

gmartin1215

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I found these rear control arms from Apoc, but I have found no opinions on them on Tahoes/Yukons.

 
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Those look pretty nice. I just ordered a second full set of factory arms for the Yukon so I won't be doing aftermarket control arms at all. I am wanting to do the panhard bars still. I'm pretty sure the Yukon's bushings are worn out because the tires rub the rear fender liners when turning hard much more than in the Escalade. There are some no-name versions on eBay that look awfully similar to the Spohn but I don't know if the savings is worth the risk of cheapo parts.
 

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