One of the things I've been chasing last year was how to get more negative camber, without having to resort to noisy camber plates. I started off seeing how much the stock components could be pushed (-0.6deg), followed by Superpro's camber adjustable bushings (-1.1deg). Powerflex also has a camber adjustable bushings, but the adjustment range is the same as Superpros (+/- 0.5deg). RWD owners are lucky enough to be able to use M3/4 lower control arms/wishbones, but it's a bit interesting since you need to put shims between the bushing and subframe mounts. xDrive owners are out of luck with that method as Kies Motorsports found out.
I read in the 2-series forum that K-Mac had made a camber adjustable bushing, and was able to get a larger adjustment range than Superpro or Powerflex. I got in contact with them last August, and found that they did have a design, but it wasn't very well vetted since Australia doesn't get xDrive cars. So after a significant amount of back and forth, and multiple revisions, I feel comfortable that K-Mac is in a place to deliver a solid product to us.
K-Mac's bushing (PN 193616-8H) uses a steel core "main bushing" encapsulated by polyurethane caps and steel washers which go between the subframe mounts. On the opposite side of the subframe mounts go "bite washers," which clamp the bushing in place to hold the camber setting you want. The polyurethane caps are two pieces, so you don't need a press to install this bushing, and you don't need one to remove the original either since K-Mac includes an extraction cup/tool (however I didn't use it and did use a press to remove my old bushings). Adjusting the camber is easier than other solutions too. You just use a regular socket or wrench and turn the head of the included bolt to rotate the bushing/camber setting. No proprietary skinny wrenches required!
All the pieces with "teeth" are meant to bite into the subframe mounts, and the end washers need to be even/on the same plane as the ends of the main bushing so both sets of teeth can bite. There's a washer with tabs to fold and "lock" the nut in place that the main bolt screws into, but I don't recommend using it. Torquing the nut to spec (100Nm / ~74ft-lbs) crushes the washer and you'll need to use a dremel to cut it off. Note that the bolt included isn't a torque to yield bolt, so don't do the extra 90deg after torquing to spec.
So after all was said and done, what camber was I able to get? -1.8deg! This is -1.2deg more over stock, and right in the range I was hoping for (-1.5 to -2deg). It made a very significant difference at the track this weekend and my tire wear and corner grip was noticeably improved. In addition to the two track days I had this past weekend I've also put about 1500mi on them in daily/weekend driving. I'm glad xDrive owners finally have a non-camber plate solution that you can get a respectable amount of negative camber with.
*EDIT* I finally got around to making a video on these:
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Originally Posted by Index
0:00 Intro
0:36 Components and assembly
5:23 Arm/components orientation in sub frame
6:34 How to adjust camber
8:32 Design positives
10:46 Design negatives
13:17 Closing remarks
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