camber curve and antidive

[mudcrasy]

I am trying to build my own upper contol arms for a metric dirt car. The stock locations can not be altered. I have been working on this for a few days now and was shooting for mounting them parallel to the center line of the chassi with 0 antidive. Finding that impossible to do.Have mocked things up a few different ways and have gotten about 1 1/2 camber gain per inch,1 1/2 caster gain with 3 inches travel and the control arm shaft is at 5 * upper hill in the front. Is this ok or am I going in the wrong direction? Also any advise for the left side would be helpfull so I am not shooting in the dark when doing that side.

John

[mudcrasy]

Yes I am making my own arms.

[dirtman45]

About all you can do is shoot for getting your initial camber and caster where you want them to be with no shims. The mounting points are what makes it pivot and you can't change them. The more uphill angle you can get into the LF arm the better it will try to gain + camber but your lucky just to not lose what you already have. Mine will track through the corner with the LF straight up at a right angle to the corner. Most others are sucking in at the top.

[speedbuggy]

... shooting for mounting them parallel to the center line of the chassis with 0 antidive. Finding that impossible to do. ...

This is true. You can't change anti-dive nor run the UCA parallel to the chassis without moving the mounts.

[fast_crew]

You could probably get away with welding up the original holes and redrilling them to remove some of the anti dive, and get alittle more UCA angle.

[mudcrasy]

So I have tried a few things and was able to get a 7 1/2 arm with the cross shaft at 7* or 5*(stock was 10*). Dont know the caster camber gains didnt take time to check it. But what is a good caster camber gain to start with and what is the dfference in handling with more or les cross shaft angle?

[dirt2]

mudcrasy
check your PM

dirt2

[hotshoe65s]

This is true. You can't change anti-dive nor run the UCA parallel to the chassis without moving the mounts.

If your making your own A-arms you could take a thick steel plate and weld it too a steel tube with an I.D. a couple thousands larger than the diameter of the A-arm cross tube. Then you could bolt the steel plate to the mount and weld the oversized tube to the top of the plate. Thus raising your pivot location. You could put this on the front to reduce dive or on the rear to add dive.

I don't know if I've explained it well enough, hard to describe without images. I honestly don't know how this would work without plotting out the force vectors and doing stress analysis. But if your willing to test it, it might be what ya want.