A four hour job on Saturday morning led to the removal of the observatory roll off roof wheels (they were low profile 1″ rollers that did not roll well) and the installation of new 2.5″ wheels (4 on each rail) mounted on a 2″x4″x8′ piece of lumber.
Additionally, a 2″x4″x8′ fence was attached to the wall, to keep the wheels on the rail, and then after the fact, a 5/4″x6″x8′ piece of cedar was attached to the rolling roof section as a skirt to block the open gap where the wheels were.
Cedar will also not require staining and will not rot (as we discovered some 10 years old pieces of wood). This will stop blowing rain from getting in.

The acid test – moving the roof with much less force… and it worked! Right out of the box as it were.
History: we started with teflon pads and melamine to slide the roof, but that quickly broke down once the roof has a little bit of snow load on it. The friction was just too much. What followed over the years were various low profile wheels to match the design of the teflon pads. In the end, larger wheels had to be added, needing a redesign of a lot of the roof structure, stops, end wall extensions, holddowns, etc. There still exists gaps at the end of the wheel structure that needs to be plugged with something flexible, in case it comes into contact with the rail.