can anybody tell me how to go about setting up my camber and casto etc, or will i need to get it done professionally, thanks in advance
not much to it really. Castor is set up in the wishbone brackets, and isnt usually adjustable. Swiveling the mushroom insert on a sierra hub affects
both camber, castor and KPI, so it isnt really much of a way of changing things.
Camber, just make the wheels upright. Either do it by eye, or make a simple pendulum device to be accurate.
I'm pretty sure swivelling the mushroom insert doesn't affect castor. I think I remember discussing it with Darren of GTS Tuning.. it's
the angle between the balljoint centres and vertical that matters, and swivelling the insert doesn't change that (the upright will be tilted back
or forward but will still rotate around the same axis relative to the car).
It would change camber though. kpi.. can't remember how kpi is worked out 
turning the mushroom affects drag, which has the same effect on self centering as castor. but yes, the actual castor angle wont change.
interesting quirk of language evolution - a real castor has zero castor angle - it relies on drag!
Bob C
I thunk castor was important for camber changes when steering, which you won't get by twiddling the mushroom.
This talk of drag is over my head though.
quote:
you won't get by twiddling the mushroom.
It would be possible to make adjustable caster buy making the width of the brackets wider for the upper wishbone. This would allow the top wishbone to
move forward and backwards adjusting the caber on the upright using washers/spacers to hold it in place. I'm quite suprised I have never seen
this done, especially on the race chassis's.
With regard to the sierra mushroom adapters surely this would adjust both caster are camber as it works in a similar way to the adjustable strut top
mount you can buy with McPherson struts? I've seen them used on hot-rods and other race tin-tops. By rotating the joint you get caster and camber
adjustment...
Andy
A few people have used wider brackets and shims to adjust caster. I've also seen a shimmed wishbone made of separate legs and balljoint mounting
tube bolted together with shims between them..
I'm not sure about adjustable strut mounts, but rotating the mushroom doesn't adjust the castor with a sierra upright, as it doesn't
change the angle between the balljoints and vertical, which is what castor is. It does make the upright lean back and forward which may have other
effects, but it's not changing castor angle.