!s there is no decent supplier of "high castor" top front wishbones for the Indy, I've been looking at alternatives. It seems that the top bones for the haynes roadster have the correct distance between the polybushes as well as the correct distance from the centreline of the bushes to the end of the threaded tube (which also takes a transit drag link). For the roadster, the "setback" of the threaded tube seems to be 24mm (i.e. the threaded tube is 24mm behind the centre between the polybushes). If someone has some indy wishbones on the bench, could they measure this dimension? It's very hard to accurately measure this in-situ. If the haynes roadster bones have a bigger setback, we might just have a (cheap!) Supply of alternative bones.

Thanks!
Sebastiaan

Ps. I don't have the time to manufacture my own wishbones, so would rather buy off the shelf
Ps2 let's not get into a discussion on the required castor please...

If the inboard dimensions match the Indy then I would hazard a guess the other dimensions do as well.

That't be my guess too, but I'd like to confirm that.

Hi

You will need to go Rose jointed or narrower bushing than original to be able to set the castor to what is required individually from chassis to chassis and side to side. IE adjust ability forward / back is required. This is why there is no real off the shelf supply as and fit no two the same.

If wanting them made to suit the individual chassis then there is people who do do this.

Cheers Matt

Right, a long overdue follow up on this.

<short version: Haynes top front 'bones fit an indy and give a 2,3 degree increase in caster>

I've just taken one of my front top wishbones of my Indy and compared the main measurements to the Haynes roadster book. My Indy is one of the early ones, so not an -R and with round tube top wishbones.

The distance (or lenght, if you will) over the bush tubes seems to be the same as the roadster at 229 mm and the bush tubes are 35mm long on both, so the Haynes bones will fit the MK chassis.

The width of the Haynes bone is some 9mm more than the MK bone. BUT I have 15mm of thread showing on the top balljoint, which would mean that I'd be able to compensate for the increased wishbone width and have a lower bending moment on the balljoint shank as a bonus. I'm running 3 degrees negative camber by the way, so for most people there should be more room for adjustment as I guess most people run with a bit less negative camber anyway.

And now the big one. The "set back" of the wishbone (I.E. the distance from the centerline of the bone to the balljoint threaded tube) is 8,5mm more on the haynes bones than on my Indy bones. This would mean that the Haynes wishbones have MORE caster compared to the MK bones. A quick measure of the Sierra uprights tells me the balljoints are about 210mm apart, so the 8,5mm increase in setback would give around 2,3 degrees of additional caster. Which could be a useful amount to aid self centering...

Now, I'm trying to finish off the chassis improvements (see other thread in the MK section) and might be ordering a set of haynes top front bones to see if these make a difference to the self centering with the increased chassis torsional stiffnes.

O, and please no more comments on how all MK's are different and not properly jigged etc. We've all heard that many times already.

E.F.S.

[Edited on 26/2/12 by sebastiaan]