Suspension

[ToyoHabu]

I am aware that the rear axle suspension follows a complex path, what I am not yet convinced of is that this requires the control arms bushings to have 2 degrees of freedom.

The A-Arms are definitely only single degree freedom, rotation.

After looking at the lower control arms and the associated bushings, there cannot be much rotation perpendicular to the bushings axis.

Does anyone know of a good kinematics simulation program for suspensions?

found this one http://www.kangaloosh.com/cms/
but does not yet do multi link rear ends just double uneven wishbone or De Dion

 

[Wiisass]

You do not need a kinematics program to see that the suspension pivots do not maintain a constant axis throughout travel. All you need to do is look at the geometry and you will see it. If that is not enough, then unbolt the shock and move the suspension through it's travel with a jack.

And you can't look at each arm individually, you need to look at the whole package. Suspensions follow arcs, but from the front view and side view during travel. This arc is determined by the geometry.

But just unbolt the shock and look at it. In the rear, I'm not even sure that the upper control arm inner mounts share an axis. They look close, but I haven't confirmed it for myself yet.

As for other kinematics programs. There's MSC.Adams, Suspension Analyzer, Susprog3d, Bill Mitchell's Wingeo, sweet excel spreadsheets that you make yourself, etc. There are a lot of options out there, ranging in price from affordable to really expensive. But I really don't think you need a kinematics program to tell you what you're asking.

Tim