I would have though that you'd also want to minimize both brake dive & acceleration squat, rather than minimize the castor change when they occur.

I would have though that you'd also want to minimize both brake dive & acceleration squat, rather than minimize the castor change when they occur.

Well actually the high roll-center of the VXI ought to minimize dive and squat in the first place, you're right.  Even beyond that grip while braking/accelerating should be improved because the tires remain a optimal camber (not castor, that's totally different and is no different on the VXI than really any other suspension) and the lack of scrub ought to factor in as well.

When a normal independent suspension gets dive/squat the camber changes to something less than optimal (really it's less than optimal to begin with and then gets worse) as well as scrubbing out/in which increases tire wear, builds excess tire heat and ultimately decreases grip.

Whoops - that castor is a typo - it should have said camber, I do know the difference.

With regard to camber change in a " normal independent suspension" under dive/squat - that would depend on your definition of normal - I believe the most common independent suspension would probably be McPherson strut and yes camber change occurs there,  however vehicles do exist (and I have owned one such vehicle) with independent suspension on which the camber does not change with the vertical movement of the suspension, provided that both left & right sides rise & fall to the same extent, as would occur with dive & squat.

As far as scrub goes - on that particular vehicle - there was some scrub on the front tires with vertical motion, but none on the rear.

A double-wishbone is about the best there is for eliminating camber-change during suspension deflection, followed by a multi-link and then a strut.  All of them do have some amount of camber change however and the amount varies depending on the geometry of the suspension.

Traditionally there's always been a trade-off with independent designs between high wheel-travel, good roll center and good instant center.  A high-travel double-wishbone typically has a very poor instant-center and roll-center.  With that design if you try to get a better roll center you generally have to give up travel and probably the instant-center optimization as well.  The VXI simultaneously optimizes all these aspects without any compromises.

This would be good with in hub electric motors

There is a new article out in Machine Design Magazine that can be found here:

http://machinedesign.com/article/inventors-corner-a-new-twist-on-a-fully-independent-vehicle-suspension-0504

Enjoy!

This would be good with in hub electric motors

I like the sound a that!