What does CARC refer to?

[Huzo]

I think I get what you're saying.  In all fairness, you're way out ahead here.  I am humbly reminded of my personal light bulb going off long ago when I realized "Oh, the differential does it's job in part because the wheels are in contact with the road", or "Oh... the gears in the transmission are still turning because the wheels are turning too".  Thus my not so surprising insight is, "The cantilever mechanism (CARC or Magni)  will behave differently depending on whether the wheel is in contact with the ground or not".  I'm reasonably certain you've already thought of that.

Matt

Well yes, but the path of the rear axle, RELATIVE TO THE FRAME does not alter.
The linkages are constant length and the geometry remains the same.
(It's an arc...) That's what the "ARC" stands for in "carc" !!!   

[leafman60]

Compact Reactive Shaft Drive – also known as Ca. R.C. or CARC – introduced with the Breva 1100 in 2005 emulating the BMW Paralever design and serving the same function.

Nothing related to the famous Carcano who designed the V8 and the first 90 degree VTwin sold first as a 1976 model.