At list ,today ,i got the Robart wheels (but not the inserts) so i cut the hard foam from another pair of lite-wheels and stuff it inside the Robarts.No case to deform anymore. Also , i made a modification in the base of the retracts,i glue a piece of 3 mm plywood in the rear beam,so that the wheel ,moved about 20-24 mm forward (when in the open position) and away from the Center of Gravity.This should give even better ground handling ,i hope. I will test it on next Sunday.