Lotus Elan

Offset Trunnion bushes

PostPost by: vstibbard » Tue Aug 07, 2012 9:28 am

Hi,

Have made offset trunnion bushes in past to set camber accurately without resorting to adjustable top wishbones? I'm assembling S1 for road/rally use and was planning on using bronze or similar measuring camber at ride height then drilling the bush the requisite distance off centre to provide desired camber 1.5-2deg for modern motor sport series radials I expect.

Then intend to drilling trunnion and with grub screws 2-3 of them tap into bush to lock the bush/trunnion in place.

I've also heard of another material that is lubricated by ater and used in industrial machinery, take high load and is light.

Thoughts or alternative solutions?

Cheers

V
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PostPost by: toomspj » Tue Aug 14, 2012 7:01 pm

Easier way is to slot the holes in the upper wishbone where the top ball joint bolts in place. Either top or bottom you need around 6mm of adjustment to gain a degree of camber (which will be difficult to get in the lower bush). Yoko A048 tyres like 2.5 deg and more if you can get it (but looks a bit silly beyond that point).

The bushing material I generally use is Nylatron - very hard wearing and easy to machine.

Getting the castor right is just about as important - you really want around 5 or 6 deg of castor (as per the original S1) - it makes a major difference to cornering grip.

Paul
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PostPost by: vstibbard » Wed Aug 15, 2012 11:07 am

Hi Paul, thanks i will be using yoko or like which are approved, and in past have run 2 plus deg on an Alfa any less and the car seem to roll across tyres and scrub outer edge.

Its difficult to adjust caster based on design as the trunnion limits any caster adjustment in my view. To achieve itbreally need to use caterham type trunnion assembly.

V
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