Is too much negative camber bad?

[NoSoup4U]

I was reading through some threads and it seems that a lot of people try to get as much negative camber as possible. However, is this always ideal though?

a) When you have a lot of negative camber, it reduces your straightline acceleration and also your ability to brake, correct?

Thus, isn't braking an important aspect of autocross?

b) With negative camber, do we not have reduced tire patch? Thus, in a slalom, isn't this hurting us?

c) Thus, whatever is recommended for autocross, when I goto the track, I should change the camber settings to something more normal? I should not run an autocross setup at the track?

TIA

[bren]

I doubt much from an autox setup translates well to track.

I would think you could use more camber in autox since the g-loads are higher and straight-line stability is less of a concern.

[Doby]

The camber settings would be ok for the track, it's the aggressive toe settings that are not.

The reason that the BMW guys try to get a lot of camber up front is because of the strut/suspension design. With a car like the corvette with unequal lenth arms, they gain negative camber when the suspension is compressed, but with the design on the BMW it does not. The only way to truely tell if you have enough or too much is to take temp readings after each run. If the temp is even across the tire, then you're good. Too much on the inside=too much camber, while too much heat on the outside=not enough camber.

The rear suspensions on the BMW's is great however. You can get away with only a little camber in the rear which will help with straightline grip.

The front is a trade-off however with braking.

[jkuper]

I think toe out in the front helps with turn in, but hurts at speed. What I did last year was -1.7 camber on the street with 0 toe. -2.7 at the track with ? toe out, -3.7 with ? toe out for autocross. I liked the settings and the tire temps seems good for at autox. I never took them at the track, I don;t think I owned a pyrometer at the time. Or maybe Doby had it. Either way, car felt good. Toe out increases with more negative camber added. I think someone on Roadfly has a chart that will give you a good idea of how much toe will be at x.xx camber setting if you know your starting point. Ask around, I think KEF or Krumph did a chart with Dr.Gs help. Tunning a good amount of camber on a daily driver will not wear out tires dramatically quick, but toe out will. This is on the front. I think you want a little toe in for the rear.

[Doby]

Didn't I give your the pirometer back?

[jkuper]

Or maybe Doby had it.

You did no worries

[bren]

I think someone on Roadfly has a chart that will give you a good idea of how much toe will be at x.xx camber setting if you know your starting point. Ask around, I think KEF or Krumph did a chart with Dr.Gs help.

IIRC it was something along the lines of 1/16 of toe per degree of camber.

[jkuper]

IIRC it was something along the lines of 1/16 of toe per degree of camber.

I think it depends on wheel sizes as well....

[Nick325xiT 5spd]

A lot of it depends on the tire. The only good way to do it is with a pyrometer. FWIW, my RA-1s liked ~4 degrees at the track.

[Pinecone]

Negative camber in the rear reduces stairght line acceleration due to the reduced contact patch.

In cornering, the loads push the tire flat (along with the body roll) so you are putting in negative camber to make the tire flat when cornering. WIthout the negative cambe,r the tire is not flat when cornering and you are reducing the contact patch.

And since cornering is more important than straight line acceleration in autocross, negative camber wins.

Can you get too much? Yes, but in a BMW you will have to work VERY hard to get that much.

[Doby]

Negative is the rear isn't nearly as important then the front on BMW's. The rear suspension (E36/46) does a great job with camber curves and such, and the negative camber isn't needed as much in the rear.