My Mom is an older solid upper intermediate to lower advanced skier with decent skills but limited angulation and flex ranges. She's currently in a Lange Comp 90 (I believe) that was fitted and adjusted last year by a reputable fitter (Rob @ Sun and Snow in Ann Arbor) to address arch/instep issues and control problems.
For several years she was skiing strong and balanced on 150 cm Volkl P60 SL World Cup Juniors with Marker 14.0 Piston Control bindings mounted on a demo track. Then, two (maybe 3?) years ago she purchased a pair of 163 cm Volkl Auras mounted with Marker Griffon bindings and has been skiing them constantly ever since, consistently getting faster, more aggressive, and more adventuresome. Friday, however, we had really icy conditions and she chose to go back to the P60s for the night, only to have her tips wander and chatter to an annoying and confidence busting degree. She stayed on the blues for the night and found she could mostly get the tips under control but she had to really drive forward aggressively and concentrate on maintaining tip pressure through each and every turn. To say she was a bit frustrated would be an understatement.
I know; 1) it could have just been the conditions, and 2) it's hard to tell without video and pictures of the equipment set up, but my gut reaction to this whole situation is that the heel lifts in her boots that keep her balanced on the Auras with the zero delta Griffon are causing an over-ramped situation on the SLs with the Piston binding.
Is this a very real possibility or am I just grasping at straws??? If I'm off track, can you suggest other possibilities?
If over-ramping really is the case, is it likely that a gas pedal can be put under the toe mounting area of the Piston demo plate to correct this?