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Hello everyone, my name is Jason and this is my first post. I have been pondering over a Locost/Exo build for a few years now and I think it's finally time to build something for myself for a change.

I'm trying to determine what steering rack, knuckles, rear diff and cv shafts to use which brought me to a simple but yet important question.

Would it be ideal to have both front and rear unequal control arm sets be identical? You would then tune roll center with the control arm angles. The angles of the front set being slightly different from the rear set.

I have poured through many articles and couple books, many had great insight to each end and would allow me to make an assumption but none addressed it specifically. I would also assume the car would like less camber gain in the rear and perhaps a lower RC (in relationship to CG) than the front.

If anyone has any links to any articles or books, I would appreciate it very much. Most likely, I am going to order material up today



Jason

Yes, that's been done. I know of one car that used Corvette rear suspension front and back (with a different spindle). That was the Packard relaunch (failed) with the Falconer V12

So in reality it's not worth the future tuning aggravation and I should just make each set what it "should" be. I'm getting quotes now for used c5 setups. Figure that would be a good starting point.

Lots of mid-engine kit cars in the UK (notably GTM) have used Mini suspension and subframes both front and rear, with the steering being locked at the rear using fixed tie rods rather than a steering rack. This obviously give you identical geometry, including roll centres, front and rear. Whilst in theory this isn't perfect, in practice it seemed to work pretty well; the GTM was regarded as a well-handling car.



There are no hard-and-fast rules - and you can juggle other factors (spring rates/ARB rates, tyre widths and pressures, etc.) to balance against geometry - but for what it's worth, it's normal to incline the roll axis of a RWD car downward toward the front (ie. higher roll centre at the back).

The effect isn't massively pronounced, but you'll find that this makes the car lean progressively more on the outside front corner, as it rolls, thus loading the tyre at that corner more and promoting understeer.

Roll understeer is generally a better idea than roll oversteer.

Maybe.
Whatever gets you around the corner.

Two of the best handling sedans of the late 60s- the Volvo 140 and the Rover 2000TC were specifically designed to have a final, gradual roll over steer. Live axle and DeDion, respectively.