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Discussion Starter · #1 ·
I see that a lot of folks seem to have negative rear camber regardless of lowered or not. What do we thing the possibility of making a camber adjustable set of upper. rear control arms?

It seems like a tube steel version should be doable.


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Discussion Starter · #3 ·
I was thinking that the physical design of the upper arm is simpler to fabricate.


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Maybe I need to refresh my memory, but if I remember right the upper arm is a complicated 3 point mounting at odd angles, sometimes tube welded and sometimes forged. It takes load in three or four directions, which makes an adjustable joint a nightmare. The lower arm is a two force member which would make it far easier to replicate with an adjustment.
 

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IPD has a special offset bushing for the lower control arm (bolt hole is off center). Apparently it takes some skill to install in the right location to get the camber in spec. More than I wanted to deal with ...and mine are both still "in spec", meaning less than 1degree negative...although even with that, the insides of our R tires wear faster...
Funny how we don't have that on the other 2 Volvos in the fleet.
 

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For lowered R's the IPD camber bushing is not enough. My memory is the same as Lloyddobler, the upper arm is a complicated 3 point arm. The lower would be easier. Or maybe another offset bushing at the knuckle?
 

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Discussion Starter · #7 ·
I would love to have something adjustable by the end user. Instead of just all out.


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Why go for the hard to get one that is in compression. The lower arm would be the much better way to go about attacking the camber on the rear of an R.
Is there pro or con to upper vs lower geometry wise?? We aren't talking much difference in total movement (1/4 to 3/8 inch??) one way or the other... but even a small amount over the full travel of the suspension the angles can change a fair amount.

Wonder if RBbugBITme would comment...
 

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I looked at the upper and don't even want to consider it.

The lower is also not a two force member due to the shock mounting which is also unfortunately mounted off the axis between the two ends which means the shock is constantly trying to twist the control arm. That can be a PIA if you're looking at a turnbuckle style adjustment mechanism. I have been looking at a shim based design but haven't pursued it do to liability and cost concerns. Once I'm done designing the coilovers I will start looking at this again.
 

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i do not believe it would be that hard. i took mine out the other day. its just to get it where you would want it would be difficult..

i think for an adjustable one, instead of it bolting at the knuckle, a bolt will still go through the knuckle but maybe theres a way you could make a sliding bracket to make it bolt higher or lower on the knuckle side.

or im just speaking nonsense but thats a way i could see it possible.

Edit: i was re reading this and i didnt really make it clear. when i said bolt on the knuckle side, when the bolt goes through the knuckle to bolt onto the control arm maybe there would be a way to make a thicker control arm with a track in it thus making space to move the bolting location on the arm itself higher or lower.


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Discussion Starter · #13 ·
You would need a twist resistant mechanism then. Makes sense.

I wish something like this would work. Doesn't seem so with the offset shock mount.

https://www.vividracing.com/catalog...bJwu4lg5Gv-qL8ZNwHYBem26O8clJPOzbwaAkpy8P8HAQ



I looked at the upper and don't even want to consider it.

The lower is also not a two force member due to the shock mounting which is also unfortunately mounted off the axis between the two ends which means the shock is constantly trying to twist the control arm. That can be a PIA if you're looking at a turnbuckle style adjustment mechanism. I have been looking at a shim based design but haven't pursued it do to liability and cost concerns. Once I'm done designing the coilovers I will start looking at this again.
 

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Reviving this because I've been giving this a lot of thought lately. I kept thinking about a turnbuckle style adjustable lower control arm like this:
View attachment 46357
adjustable rear lower control arm brz.jpg

(ignore attachment links, fixed photos)


Like you guys said, the lower shock mount is offset though. The adjustment point should be placed as close as possible to the end of the control arm closest to the center of the car to reduce stress. I think after tons and tons of up and down strokes of the shock, that jam nut might come loose. But what if you combined this turnbuckle style adjustment with something like this that could help stabilize the twisting force from the shock mount?
adjustable rear lower control arm cayman.jpg


It would have a threaded rod with jam nuts as a primary way of adjusting and have the two slots with 4 bolts to help stabilize the arm from twisting.


View attachment 46359


I met a guy who does cnc work and is willing to work on things I send his way. First project I gave him was just boring out the hub on a set of steel wheels. Currently we're working on 2.5" spring adapters for the upper rear spring seats so that I can run standard 2.5" coilover springs with my KW V2s so I can play around with different spring rates. I'm really interested in trying to design something that he could CNC out of some 6061 aluminum.
 

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I don't really like the idea of offset camber bushings, not easy to adjust and have limited adjustment range. Fixed the photos in my previous post, any comments on that idea? Should lower shock mount be moved from stock location or keep the same?
 

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The trick is going to be getting a company that can properly engineer the arm. If you just make something for yourself, that's fine, but if you sell a product, there are major liability issues.

My car is lowered on ERST springs, roughly 1" to 1.25" lower, and the iPD bushing provided enough adjustability to get my car into spec (using modified stock toe arms as well). I can't imagine going much lower, I scrape on things all the time (front mudflaps and exhaust). At this point, I'd just go air if I wanted lower, there are so many advantages to it.
 
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