I have an '07 Z06 and both rear tires are wearing noticeably about 2-1/2" from the outside edge. At this point I have significantly more tread left on the inner half. In an attempt to extend mileage on these tires I'm thinking I want to increase negative camber. I have noticed that at each of the upper A-arm attachment points there are 2 identical spacers. If I were to remove one, or both, I know I would increase the neg camber, but will it impact caster and toe. Is there a better, or simpler way to go about this?

 

The C5 and C6 suspension adjustments are made by eccetric cams. There are four cams on each wheel. They are used to control all wheel adjustments. There shouldnt need to be any shims added or removed.

Bill

 

The hardest part of a wheel alignment for me is actually accessing the cam bolts. The car needs to be sitting on its tires at normal ride height. If its not sitting on a rack, the cam bolts are about two inches off the ground, **behind** the wheels.

 

You cannot do an accurate alignment yourself. Unfortunately even a professional front end Tech will not able to stop radial tires from wearing further once they are badly worn. Later! Frank

 

Not true! I've always done my own alignments, and never had any uneven wear problems. Car tracks true as an arrow! Front end shops don't have time to d!ck around getting it as close as I want it. I do.

 

Like I said: You cannot do an accurate alignment in your garage. Tire wear is only part of a good alignment. Every time you turn one eccentric you are changing camber, caster and to a small extent the toe in/out. I was an alignment Tech for five years and did over 5K alignments. There is nothing special about adjusting the front and rear on our Vettes. They are quite easy on a good machine. Doing your own alignment on a C4 is a different story but still not recommended. You can play around with them by removing/adding shims. If you screwed up you could reverse what you did. My shop did an excellent job on both my C4 and C5. Later! Frank

 

If there are an equal number of spacers removed from each bolt holding the upper control arm to the frame you would not affect caster. However, you have no idea how much negative camber you have at that point and the toe adjustment will be affected as well.

When setting alignment camber is set first, followed by caster (which affects camber), and finally the toe is set. To get more positive caster you can move the rear lower control arm mount outwards relative to its front mount or move the front upper control arm mount outwards relative to its rear mount. Both of these actions will affect camber. All camber and caster adjustments will affect toe but toe adjustments will not affect the other two.

With the right equipment (camber gauge, toe plates or a simple method of stringing the car, and a tape measure marked in 1/32 incrments) you can get an accurate alignment doing it yourself at home but it isn't easy. I did it on my 97 for a few years so I could move back and forth from street alignments to track alignments. The adjustments are easy to make but each time you jack the car to make an adjustment means you have to settle the suspension which meant driving around the block and setting everything up again. Each alignment would take me about 3 hours.

As for the accuracy of modern alignment machines a lot depends on their calibration frequency, operator experience and whether the door is open or not. I just had my car aligned in May and the settings were never really steady. Between the normal variation that occured as the car just sat there or the extreme variation that occured when the wind started blowing in the open doorway it was hard to get a dead on setting. Close was all that was achievable. Every time the car was moved to settle the suspension after an ajustment was made previously set readings never returned. For instance the rear settings were made first followed by the front settings. Each time an adjustment was made on the front the rear settings changed by some small amount even though they had not been touched.

Bill