Shimming the rear for negative camber
 

Has anyone ever attempted shimming the rear wheel (hubs and calipers) of a 2009 LSJ to get more negative camber (it's a Brembo equipped vehicle)?

For those unfamiliar with alignment shims, they are the normal way to adjust non-adjustable wheel alignment settings -- usually used after a wreck to get the alignment back to spec.

The factory specs state the minus .80 is spec for the rear wheels and it states that plus or minus .75 is within spec. Which means 'if' it can be adjusted (with shims), I could get -1.55 degrees of negative (legal for DSP).

I've did this successfully with a 2006 Saturn Ion Redline -- shimmed behind the caliper brackets (so both the hub and the calipers camber the same) -- got -1.5. It worked very well. It tightend-up the rear end, I could carry a lot more speed without much oversteer.

My most recent fresh-tires experience, up at the National Tour event in Packwood, WA, demonstrated that my rear slicks are only operating on the outside edges (perhaps the outer 1/3rd got almost all wear) -- even with 650 lb springs and a monster swaybar. The fronts evidence full width wear with about minus 2.0 degrees of camber.

Back to the question, looking at the factory maintenance manual, I can't really tell 'if' the late model caliper brackets are bolted to the axle -- or not. 'If' they're bolted to the axle, I can do the mod.

I'd prefer to know that it's possible before I dive in and make changes.

Thanks for any input.

Scott

umm you have a 09 LSJ?

yup http://www.turbotechracing.com/produ...dcategory=5627

I think he meant LNF.

;):twothumbs

thats simple for the front. he is asking about the rear

Didn't FF_Drift_lol do that?

I've read that it's not possible due to the way the caliper bolts up, and the shims are generally plastic, meaning they will wear pretty quickly.

Let us know if you manage to make this work. I'd be more interested in it for the toe adjustment than camber. I'm happy with how my tires perform in back. I need LESS traction in back, not more :-P

Yeah, yeah, yeah, a typo...

Scott

Bump did anything happen with this?

Yes, I'm working on it. I just received a plate of 6061 aluminum last week.

Scott

I'd like to see a little more of this experiment.

army greywolf already did this. It's been working out for him. He posted about it in another thread too.

I'd be interested in seeing his results - and methods.

Adding to my earlier, if any of you have an 07 or earlier (I had an 06 Redline) and you look closely at the rear axle, you'll see that the hub bolts through a steel plate and the caliper bolts to that steel plate - and the plate is separate from the axle. It's easy to shim the entire plate out to 1.5 degrees of negative -- I did it and autocrossed that way for some time (BTW, the shims are nylon and steel and I found no significant wear after more than 25,000 miles of use).

On my 09 Cobalt, the 'steel' plate the hub bolts through and caliper mounts on is welded to the axle -- no way to shim without screwing up the caliper/disk alignment -- a bad thing.

So I plan to pull the hub and the caliper and (using construction paper) make an exact copy of the layout of the steel plate -- I'll transfer this to the 3/8" think 6061 aluminum plate and make an exact copy. 'If' the ABS sensor can be wired through the 3/8 aluminum plate and throught the 3/8 steel plate, and I can move the caliper out 3/8" (shouldn't be a problem), then I'll cut off the caliper mounting ears from the steel -- smooth everything down, and remount the hub through both plates (there's plenty of bolt space on the backside) and remount the caliper to the aluminum plate.

This way, it would be the same as the old 06 and I could shim between aluminum and steel -- I hope...

SCCA legal, and I can 'legally' get up to -1.55 negative camber.

PS: just had the existing alignment checked -- currently stock: left rear -0.27 camber - right rear -0.60. No where near the -1.55 I want.

Scott

Give me a couple days, I have alot to do on Monday but if I get my jobs cleared I think in the afternoon on Tuesday I can get my car on the rack to show how it's done. The shims are a type of plastic that helps them bed but I have NOT had camber or toe wander whatsoever.

I'm very familiar with alignment shims, I used them on my 06 Redline to get -1.5 of camber.

My question really revolves around maintaining the caliper/rotor alignment with my 09 SS.

Thanks, Scott

They have caliper shims for that exact reason.

Where do you get these caliper shims from?

Didn't know that. Never heard of them. Where do you find them.

My initial plan was to shim the hub then use washers on the lower caliper mount, but when I looked closely, it appeared that the caliper mounts were exactly aligned vertically...

Scott

I have the rear axle assembly from an 06 ss/sc in my shed and I juts checked and the caliper bolts to the plate that is welded to the rear beam.

Exactly why I'm proposing grinding off the caliper mountain ears and using an aluminum plate to mount the caliper to. However, if, as has been said, someone has shimmed the hub and the caliper, it may be a cheaper way to go. I'm willing to try anything that works.

Scott