Interesting posts above and I'll share my thoughts:
I have a theory based on what I've learned about gyros in aeroplane instruments... (and front wheels on motorbikes):
A force applied on the side of the gyro works as a force from the same side but applied 90 degrees further forward in the direction of rotation.. if that makes any sense to anyone.. pardon my English.
A force from straight ahead (a pot hole for example) on a front wheel will cause a backwards movement on the hub axle and subsequently a force sideways on the wheel 90 degrees further forward in the rotational direction, forcing the upper crossframe tube inwards and the lower tube outwards resulting in a twisting effect on the front end.Taking into consideration that both front wheels will work together through the steering linkage there will be a significant gyroscopic effect. Since the chassie frame is completely 'open' in the front end there is a possibility that the whole structure will work as a 'torsion spring' - including typical properties of such a spring - with the rotational axis in line with the centerline of the chassie frame (not the crossframe).
Together with all above mentioned possible causes (also the flexible chassis) I'm inclined to believe that this could initiate a wobble that can only become controllable by reducing the gyro effects on the front wheels (now working together in some kind of harmony...) significantly.
I have some experience from aeroplanes and motorcycles and I know that 'gyros' are powerful enough to cause trouble.. sometimes serious.
Well... these are just my humble thoughts...
but I just can't 'forget' about the possible connection between The Malvern Dance and the gyro effects. Been that way since I bought my -99 4/4.
