Track widths and wheel base

[Jimbob]

The E30 struts I'm intending to modify for the front are welded onto the strut tube, so I'll be incorporating the bottom of that tube into the upright. The position of the ball joint will be made to match as closely to the original as possible. However the E30 seems to have a much smaller caster offset than the Haynes Roadster, or an E36. I'm not sure if this can be entirely designed out with this strut, but may not really matter...

One thing that's been bugging me about both the intended Sierra uprights is that they seem to be set up for a few degrees of NEGATIVE caster (ie the swivel axis meets ground behind centre of wheel) which is the opposite to the Roadster!

Is this correct or have I made it up? It's just that this opposite setup naturally results in some horrible ball joint angles, because the casting is the opposite way round.

The Roadster caster is 6.7 degree, and the Sierra looks like it's naturally (ie with nicely lined up ball joint and horizontal steering arm) about -4.3 degrees. So that's 11 degrees on the ball joint from go. Crazy..?


Can anyone put this one to rest or have any ideas? I think I'm going mad

Thanks

Graeme,
Is there really any need to adjust wishbone lengths? If you can determine the mounting points on the uprights, then surely you can vary them to achieve correct wheel position/track/camber with the existing wishbones.

Then you wont have to re-estalish a roll centre.

James