Rear camber settling

[kyngfish]

Hi all. Working through an alignment on my newly refreshed suspension. I’m finding that on the passenger side after setting camber to 1 degree negative it usually settles more negative after I shake it out. The procedure I’m following is jacking up the rear end - loosening the bolts behind the caliper and then the toe and camber bolts. Removing the sway bar end link to give me space. Then setting camber and then tightening and measuring. Is there any reason why it settles more negative after I raise/lower and drive?

[juanbenae]

when the suspension is loaded more camber is obtained.

[aston@ultrasw.c]

This is an annoying feature of home alignment adjustments.

The suspension components have friction that prevents them from returning their happy place aka sticktion.

Also as you lower the car the suspension swings through a camber arc if you will, so the tire tries to scrub over the surface. Place a 1 gal freezer bag, with a squirt of wd40 inside, under the tire and try again. It may help.

Or you need a set of hub stands but these are spendy. Unless you are an enthusiastic metal fabricator.

[kyngfish]

So is there any good rule to follow. Like setting it a half a degree too positive and letting it settle more negative?

[aston@ultrasw.c]

Originally Posted by kyngfish

So is there any good rule to follow. Like setting it a half a degree too positive and letting it settle more negative?

Has not worked for me.

I have even recorded all my measurements, then taken the car to a laser alignment station and had it measured. Only costs $20.

Their results are not consistent with mine, I even went to another shop: now I have 3 versions of the truth

[Trackrash]

The toe will also change as the suspension moves up and down. You really need to do the adjustments with the car on the ground. As far as alignment racks go, it's anyone's guess as to how accurate some of them are. Strings don't lie.

It is surprising how a small amount of play or wear in the suspension bushings or bearings will be noticeable when measuring your alignment.

[kyngfish]

Originally Posted by Trackrash

The toe will also change as the suspension moves up and down. You really need to do the adjustments with the car on the ground. As far as alignment racks go, it's anyone's guess as to how accurate some of them are. Strings don't lie.

It is surprising how a small amount of play or wear in the suspension bushings or bearings will be noticeable when measuring your alignment.

Quick question. If I do the adjustments in the air then drop it to measure isn’t that better? Allows the suspension to resettle?

[chrismorse]

Hi Kyng,
I too have just done a suspension refresh and have concerns about settling of both the the new rubber bushings and the new Bilsteins, as well as dealing with stiction.
When I rebushed/resprung my green car, I built a level platform, long enough to allow making adjustments, over the scales, letting the car back down, rolling it back and forth about 10 feet to eliminate the inaccuracies caused by the dreaded stiction. I like the plastic bags full of grease/ lube idea, to let the tire slide out as it is lowered after adjustment, hopefully eliminating the sticking up in the air, (with inaccurate camber readings and toe as others have pointed out. Conceptually, I am worried a bit about the tire sliding on the bag and off the scales/platform - but I am a compulsive worrier - I’ll probably use the greasy bag on the scales idea, with wood stops to keep things from coming off the scales.

continuing with worrisome ideas, I have heard that both the rubber bushings AND the new Bilsteins will settle, during some un-named amount of time, thus rendering both cornerweighting and alignment compromised.
This brings up the question of “how long do I need to drive the car to allow things to settle before making a durable scaling and alignment”???
I’m a bit OCD about wanting to get the suspension right.
Good luck,
chris

In addition to all of the above, is your measuring platform flat? I find it hard to believe you would have enough anti roll bar preload to throw the camber off significantly. How are the cornerweights?

[Trackrash]

Originally Posted by kyngfish

Quick question. If I do the adjustments in the air then drop it to measure isn’t that better? Allows the suspension to resettle?

IMO, you are just making more work for yourself. Additionally when you lower the car back to the ground the tires will still need to move as the suspension settles.

[stownsen914]

I also do my adjustments in the air and then lower to re-measure. The key to consistent results is settling the car once it's back on the ground. I use "slip plates" - basically two steel plates under each wheel with oil between then. Makes things much easier. If you don't have those, the plastic bag as mentioned above also works (can use a trash bag too). Or rolling the car a couple feet back and forth and compressing the car a few times with your body weight. Whichever method you choose, do it before you measure anything.

[dannobee]

The real way to do it is with "turn plates." You can sometimes find them on craigslist, or could always turn to the Chinesium ones on ebay for about $150 new. With turn plates, they also have the protractor scale so that you can check caster. You'll need plywood of the same thickness on the other end so that the car is still level.

It doesn't matter if you're stringing the car, using levels, or a true alignment machine, the turn plates make the job a lot easier than plastic bags or waxed paper, although at the track I've used those methods before finding a set of turn plates.