Are solid axles dead?

[Norm Peterson]

I wouldn't call watt's links and panhard bars "bandaids".

When they are added to control leaf-sprung axles in directions that the leaves aren't up to adequately controlling alone, that's exactly what they are. Additional components used to cover for shortcomings in the basic leaf spring arrangement and detail design.

Technically, adding them over-constrains the axle, with the more flexible components bending, compressing, or otherwise squishing and deforming to suit the motion that is forced by the stiffer components as the car moves around on its suspension. Usually this sort of thing adds a little NVH because the forces that are developed to do all that bending, etc. get transmitted back into the car to some extent

That doesn't have anything to do with how effective the "band-aids" can be, particularly with fiberglass leaves. The less rigid the material used for the leaves is, the greater the need for them to be crutched by an additional component for what they can't do very well all by themselves.

Fiberglass springs are not cursed with the same levels of interleaf friction that most metal leaf springs end up having sooner or later. That's a direct reduction in ride harshness, which I agree is a nice development. But that does not fix the lateral location issue, which involves both lateral bending and torsion in the leaf and compliances in the leaf spring bushings and (usually) shackles. Or the matter of spring wrap.


My position has nothing to do with leaf springs being "old tech". It's based on recognizing what structural loadings they aren't very good at resisting all by themselves, what that implies with respect to suspension geometry, and understanding the side effects of adding more suspension components to help them out. I'm a big believer in each suspension component being very good at doing one thing well, as opposed to trying to do two or more things not-so-well.


Norm