Ragin' Bajan

About a year ago during a surprise (for me) snow fall, I got up close and personal with a concrete median, and ended up tagging the left rear wheel (after brushing the left front). All repairs & adjustments done and complete, or so I thought until this evening. A friend of mine commented that my rear left wheel seemed "off". I'm getting ready for track events, so I figured it wouldn't hurt to have an alignment done. Lo and behold: although the insurance company was billed for it, looks like the rear alignment was never done! The front wheels were only 0.1 degree off any of their settings(reasonable I think) but the rear camber is 0.5 degrees off the minimum settings, and consistent with being knocked against the curb. So I'll be taking it in and requesting that the Porsche dealership, which did the job, do it properly.

That's the first point, but not what I'm most concerned about: there was another discovery. In adjusting the front end, they found the left side was at it's maximum setting, at 4.3 degress (specs are 4.2 to 4.7). So it looks like the left front control arm was bent, but since it was within spec, they didn't bother to replace it. So, I'll be calling tomorrow to sort this out. As I said, I don't think getting the rear alignment done will be a problem, but I'm looking for evidence/arguments to support replacing (fixing?) the bent control arm.

I'm imagining the insurance co will argue that, while the full range of adjustment is not possible, it's still within specifications.

However, if I wanted, say, 4.7 degrees caster, it would no longer be possible. If I understand, increasing caster improves turning responsiveness of the steering wheel. Is this correct? Can I reasonably (which is a lot easier to argue than theoretically) demand the ability to set a 4.4+ caster? Has anyone done this?

Jeff Curtis

Your caster settings aren't really a big deal...as long as both sides match within tolerance. Say your left side is at 4.3, the right should be within so much of that, probably 4.2-4.4deg. - just for example.

It's toe in/out that affects turn in, and neg. camber that promotes an even tire contact patch on the road surface under load.

I wouldn't be too concerned with the caster.

Also, a .5deg. difference in camber is NOT that much, but if your rear is off a bit, certainly get it adjusted.

Ragin' Bajan

Urg, not the reply I was hoping for Looks like it'll be a long battle w/ the insurance company. Or perhaps a short, one-sided one....

Bill Gregory

If you do a search on "corner balance specs" and "corner balance alignment" in this forum, you'll see that caster settings on Rennlistrs 964's range from around 3.5 to 5.0. Caster helps with straight line stability - it helps create the self-centering effect of the steering wheel.