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Correcting geometry on low cars....

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Old 11-06-2013, 01:16 PM
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Ade
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Default Correcting geometry on low cars....

Especially the steering arms which sit at an awful angle when a Sierra is lowered. Anyone used anything successfully to space them back to a proper angle?

Track rod end extensions, or custom rose joints?
Anything off the shelf for this?
Old 11-06-2013, 01:31 PM
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fraser9764
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like this?


Just a case of finding some good quality rose joints with the correct thread, some conical misalignment washers, some spacers and a nut and bolt.

would it need the first spacer to taper into the hub like the standard track rod end does? i guess it isn't necessary so long as the spacer has enough surface area at the end in contact with the flat of the hub?
Old 11-06-2013, 09:33 PM
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Marc sierra
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If you move the steering arm down you also need to move the tca down, otherwise you will end up with bump steer.

The 3dr cossie hubs have the connections to the tca and steering arm at a lower point than all other hubs. This was specially done as the 3dr needed it for homologation purposes.
Old 12-06-2013, 10:58 AM
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Ade
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Yeah, that looks like one solution.

Marc, would correcting one arm not help reduce some of the bump steer?
Not sure why putting one arm back to a good position would be a bad thing?
Old 12-06-2013, 11:29 AM
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JonnyBravo
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Some roll centre corrected hubs would be great, look at what driftworks sell for the Nissans.
Old 12-06-2013, 06:39 PM
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Marc sierra
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Originally Posted by Ade
Yeah, that looks like one solution.

Marc, would correcting one arm not help reduce some of the bump steer?
Not sure why putting one arm back to a good position would be a bad thing?
The tca and steering arm need to be parallel to each other. Otherwise the tca might push the hub outwards during bump, while the steering arm pulls it inwards during bump, meaning the car will toe inwards during bump.
Old 13-06-2013, 10:41 AM
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I agree with Marc, you will need to correct both steering and tca. I would weld some new mounting points on the existing hub, switch to 3dr hubs or get some 18"s and highten the car. The sapphs are horrible when lowered as the roll center is far under ground while the center of mass is way up.

The extension showed in the pic above is just making things worse imo as all it does is introduces bending moments where you absolutely dont want it.

Last edited by nixon_2wd; 13-06-2013 at 10:44 AM.

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Old 13-06-2013, 11:18 AM
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lacey
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Touring car spare use to do a nice set of arms to correct geometry
Old 18-06-2013, 09:27 AM
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Originally Posted by Marc sierra
The tca and steering arm need to be parallel to each other. Otherwise the tca might push the hub outwards during bump, while the steering arm pulls it inwards during bump, meaning the car will toe inwards during bump.
As explained above ^ but too add - it happens because of the arc of travel of the rod end in relation to the arc of the hub being matched.

So the the steering arm gets longer or shorter at a different point as the suspension compresses and unloads whilst driving which cause steering input on the hub without turning the steering wheel - bump steer.

Chassis mounted engine and adjustable fabricated engine crossmember
Old 18-06-2013, 11:03 AM
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JonnyBravo
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This is what my mate uses on the Nissan s15. I believe the roll centre adjustment is 40mm. The knuckles are fabricated and take the standard nissan parts.

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