Quote:

For proper ackerman, the tie rod end should fall on a line drawn from the center of the rear axle through the front lower ball joint. Looking at a front end with stock spindles and discs, this just isn't possible.

Also (correct me if I'm wrong here) the idler arm pivots and center link pivots should also fall on a line drawn from the center of the rear axle through the LCA pivot point.
If you have to compromise bump steer, toe out at top and bottom is prefered, bacause it doesn't over steer the car in a hard turn with body roll. That dictates at least the proper length tie rods, or slightly longer.

So with the front-mount rack, it would have to be wider at the inner tie rod ends than the LCA pivots - the actual width depending also on how far forward it is. Correct ?

I'm wondering if its possible to overcome the ackerman issue by moving the rack further forward.

Does anyone know of a book that has good info on front end design?


The lower control arm arc at the ball joint sets the length of the tie rods, which in turn set the width of the rack. Moving it forward or back will not help, only mess up the angle of the tie rods. Bump steer is more important than Ackerman, provided Ackereman doesn't get too far out of whack for what you want to do with the car. I have zero in my race car, would never go less than half needed for the street.
If you have to compromise bump steer at all, it is better to toe out at top and bottom of travel. that way the car won't over steer in a hard turn with body roll.
That would be a situation where the tie rods need to be longer than perfect, and the rack would have to be shorter than is best. It doesn't take much to screw the whole deal up. I spent many hours on my street dart, getting down to as little as 1/8 inch change in tie rod length and up/down location before it looked good to me.

Last edited by gregsdart; 03/04/14 03:12 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky