Not being too familiar with the ES mounting of the nose gear, I found it interesting to learn that the bearings are inserted such that side load could move them. For the 320/360 design, the bearing seat is outboard thus preventing side loads from being able to move a bearing. Side to side movement is however just as much a concern if the spacer that separates the two bearing blocks is not perfectly sized. This is another one of those inputs to shimmy that can't really be quantified easily. Ideally one would have no play whatsoever in this joint, but also have no friction in the bearings that could impede gear free-fall. I don't know how this is handled in the ES and IV, but in the 320/360 a fixed length tube is placed in between the bearing blocks. Getting just the right length was always difficult. After a number of nose gear removals and installs, I finally decided a better design was
needed. The solution was an adjustable length spacer that allows fine tuning of the preload on the nose gear pivot bearings. A similar solution in the ES might help remove that joint as a contributor to the shimmy equation.
http://www.n91cz.com/StrutSpacer/strut%20spacer.htm