Thinking out loud: beam design mod?
 

Could this work?

As we all know, the standard torsion beam front suspension is not ideal for mainly one reason. When the suspension compresses there is no change in camber. So as the body rolls in a bend the outer front wheel moves into positive camber and grip is lost. The fix is a very fat roll bar to reduce the front body roll drastically but this has a bundle of issues for a road car.

So, you can design a fancy new wishbone suspension system and a few have but they are a big redesign and very expensive. Or you can cut up the inner wings / framehead and convert to 1303S macpherson struts.

However, I wondered if there was another possible option.

1st, leave the bottom trailing arm / torsion leaves set up as per stock. 2nd, remove the top torsion leaves and cut the end of the torsion tube at a slight angle. plate over the end and drill for a large mounting bolt. fab a custom top trailing arm with balljoint to link to the stub axle. Add coilover shocks (to replace the missing torsion leaves).

The idea is for the top arm to move in a different pivot axis (not parallel to the bottom arm) so that the top balljoint is moves inwards as the suspension compresses.

It would need a custom top arm and a carefully modified beam. However, the top arm would not be carrying the suspension loadings so wouldn't need to be as strong as the original part. Also need better maths skills than me to figure out the correct angles.

I keep thinking I've missed something (bumpsteer perhaps? loss of caster with bounce?)

Hey Bruce we are in the process of putting a 51 split bug shell onto a 73 1303 floorpan with built in strut mounts keep your peeled new thread starts next week.........

Looking forward to that! :)

Cheers

Hi Bruce,
I can see your logic but I would need to model the arrangement to see the effect but intuitively the amount of effort involved would not generate a better arrangement than a strut or wishbone suspension with the same amount of work and then it wouldn't be adjustable to allow fine tuning? Its probably doable but I can't think why you would?