Height Adjustment & Travel, Why parallel? Options

[Joseph Mills]

My 914 goes to the shop next week for alignment: 1.5 to 2 degrees neg camber front, 2 to 2.5 neg rear with 1/16" toe-out front, 1/16" toe-in rear. Tires are Hoosier A3S03's.

I have found a few posts that seem to indicate that when the A-arms and trailing arms are parallel to the ground, you have maximized your cars height. Is this in fact, correct?

If so, why is this level preferred? If you go below this height is suspension geometry adversely effected? How much wheel travel is left at this point?

Joseph
'75 914 2.0L AX bound

[airsix]

Sorry, no answer. Just extending the question a bit. I hope someone with experience and figures can jump in.

If you observe the geometry of the front suspension you will note that there is camber change throughout the range of suspension movement, with the greatest degree of negative camber when the lower conrtol arms are horizontal. As the suspension moves further from this point in either direction the camber goes further possitive.

My problem with the whole idea of arms-level-at-rest is that means you have maximum negative camber when everything is at rest. When you load up a wheel it will compress the suspension and reduce negative camber (I'm ignoring body roll - I'm just talking about the strut angle relative to the body). Does that make sense? This is why I'd really like some raised-spindle struts like the Bilstein RSR's. Using a raised spindle to lower the car and then having the static possition of the control arms below level - the amount of negative camber increases as the wheel is loaded up - at least until the travel passes horizontal - but with the right spring/shock combo you can probably keep from passing that point under most conditions. Is this making any sense?

If you start with the control arms level at rest then you are losing more negative camber with each additional pound of weight transfered to that wheel which is just the opposite of what you want. So you throw the car into a corner and you start losing negative camber as the strut compresses and the control arm moves past horizontal. Add to that the possitive camber being induced by body roll. Double wammy. You really want the suspension geometry to increase negative camber as load increases to counteract the possitive camber being induced by body roll.

Now maybe the camber you conserve due to reduced body roll from lowering the car is of greater benefit than the camber lost by having the control arms "going past the half-way point" under load. Maybe that's why people are advocating the "arms at horizontal" spec. I don't know. Ok Brad, speak up. Or anyone else for that matter.

-Ben (IMG:style_emoticons/default/confused24.gif)