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Indy Castor Again
whitestu - 21/4/10 at 12:24 PM

I've finally got round to measuring the castor on my car and it is around 3 degrees on the drivers side and 4 on the passenger.

I'd like to correct this, so I have 6 degrees both sides, and so get a bit more self centreing.

So I can either modify / make new wishbones or grind off the chassis brackets for the top bones and weld some new ones on in the right place.

It seems to me that moving the chassis brackets is easier.

Anyone done anything like this already?

Thanks

Stu

gingerprince - 21/4/10 at 12:25 PM

Someone on here (can't remember who, sorry) makes/made some upper wishbones for the indy that were rose-jointed, meaning that the fore-aft position of the wishbone could be changed by padding with spacers.

whitestu - 21/4/10 at 12:31 PM

quote:

Someone on here (can't remember who, sorry) makes/made some upper wishbones for the indy that were rose-jointed, meaning that the fore-aft position of the wishbone could be changed by padding with spacers.


I know I bought some, and never received them!

Looking to do it myself now.

Stu

gingerprince - 21/4/10 at 12:33 PM

Ah, sorry!

whitestu - 21/4/10 at 01:54 PM

Now I'm looking at the car it's clear that the brackets can't be moved so it looks like modified bones are the only solution.

Has anyone modicied their own Indy bones for more castor?



Stu

[Edited on 21/4/10 by whitestu]

matt_claydon - 21/4/10 at 04:04 PM

I'm lucky to have a set of the rose jointed ones, but before they appeared on the scene I thought it may work to just reduce the length of the tubes that take the polybushes and mount the wishbones at the rear of the chassis brackets, with washers in front as packing.

Guinness - 21/4/10 at 05:36 PM

Does anyone have a CAD drawing of what is required for a replacement top bone?

Thought I might ask one of our fabricators if he could knock up a set.

Frosty - 21/4/10 at 05:40 PM

The rose-jointed wishbones are a great idea, but the problem is the rose joints, which just won't last in the road, and most Indys will do at least some road miles even if they are mostly used on track.

The spacing of the wishbones is a brilliant way of correcting one of the inherent flaws in the Indy though.

Reducing the bush housing length would work, but I think accuracy would be difficult to achieve.

Frosty - 21/4/10 at 05:45 PM

quote:
Originally posted by Guinness
Does anyone have a CAD drawing of what is required for a replacement top bone?

Thought I might ask one of our fabricators if he could knock up a set.

It's not really the top wishbone, it's the mounting bracket itself. These seem to be located slightly differently on a lot of cars, so some level of adjustment is what's required to even up caster on both sides.

What would work well to allow castor correction is two top wishbones the same as what is supplied with the kit, but the bush housing should be shorter to allow it to be spaced slightly forwards or backwards.

This would retain road compliance, and allow slight adjustment too.

Hellfire - 21/4/10 at 06:00 PM

Give MK a call, I'm sure they could fabricate and supply you with rose-jointed top wishbones for the Indy.

We modified a pair of Indy wishbones to accept a camber adjuster and rose-joints.

Phil

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whitestu - 21/4/10 at 07:58 PM

Thanks Guys - some good ideas there.

Phil, what castor angle do you have now with the modified bones?

Thanks

Stu

Steve Hignett - 21/4/10 at 08:20 PM

U2U sent...

Hellfire - 22/4/10 at 11:21 AM

Currently running at 6 degrees IIRC

Phil

whitestu - 23/4/10 at 07:41 AM

I've ordered some rose joints so I'll have a go at modifying the bones when I get some time.

Thanks for all the advice.

Stu