Picking up where Marc left off - (Negative Camber impacts) ... this is an interesting question.

So let's dive in.

I'm less interested in tire life than safety and feel under different circumstances. With the amount of track and AutoX time i put in, out edge wear is ALWAYS my problem on stock-spec cars.

For the record i have a s much camber dialed into my 986 as possible and i lowered my Audi S6 Avant and the shop (ok, a fancy pants shop with a grand am engineer doing the alignment) got -1.75 all around. That car is wearing 100% evenly. The Boxster is wearing a bit on the front outer :-)

Ok - now the the thinking part. Lots of folks say things like "be careful with all that camber in the wet, you don't have much rubber on the road at low speeds", or "the steering may feel light and provide less feedback with such a narrow contact patch."

1. i don't notice it
2. I don't think the physics supports either statement

We have to begin with - grip is weird. It is NOT limited by friction as dictated by classical mechanics, but rather by a lower limit set by rubber shear (or, of course, debris).

Also note that tires don't follow classical pneumatics - meaning the contact patch is not unit proportional (although it is directly proportional) to the weight it supports.

At high cornering forces, where these limits come into play, we can assume the car rolls over and the camber approaches zero.

At low cornering forces the car does not roll much and the camber is still quite negative, so the contact patch is narrow.

Since we know we like - camber at high cornering forces, let's ask what happens at lower ones. I postulate that the weight on the tire is the same (duh) so much of the steering weight and feel is the same. I also postulate that since forces are low, any grip is now much more governed by classical mechanics and friction - e.g.: the cF x the weight, surface area be damned.

This means the grip is roughly the same.

Now let's ask how it handles wet conditions. I postulate that the higher force/unit area improves aquaplaning and its ability to deal with light muck, such as mud ( muddy water, residue, etc.). So in that respect it might be BETTER.

In fact, maybe negative camber provides a geometry that has hgih force/unit area when you want it, and dynamically increases surface area, and thus shear stability, as cornering forces rise.

All this says that - aside from wear (which really should be much higher, and most report it is) negative camber is vice-less.

Chime in.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

mostly for better tire wear and handling at track events. Other than slightly higher steering effort at parking lot speeds, I don't notice any ill effects on the street. Too soon to know about wear on the street tires but I don't much care and will deal with it if it happens. Wear on shoulders of track tires is noticeably better after one weekend at the new settings. Only seen a tiny bit of rain recently so no idea about wet performance changs but again, not a major concern for me. Last session on Saturday had a fairly heavy sprinkle and car did not slip on the track tires.

Agree that contact patch, etc. is affected by MANY factors besides camber. Dirt, debris, liquids, pavement condition are just reality and cannot really be controlled for. Changes to toe would more drastically affect handling in my opinion.