Very good point, sump-and-pump (or at least sump-and-suction-hose) and a slope to the floor of the "pit"
The 60ft steerable satellite dish i used to look after used a central pintle bearing and plain rollers on a flat track - it did get fortnightly mopping and re-greasing though :o) and it was nicely motorised, too! I guess that made me think of the central bearing and flat track/rollers. I'll check out prices for grooved rollers (if I can find any...)
suggestions
I suspect that chequer plate, although stronger, could prove slipperier that the grippy paint when the tyres were wet - based on experience with manhole covers in the wet!
The pit would be a bit iffy, as it'll form part of the garage floor rather than being in its own dedicated area - re access to clean and grease, it'd be easy enough to make the top so that parts could be folded upwards.
I guess this could be integrated with the handle for rotating the top, perhaps a spring-loaded rocker and pin that the handle presses on when inserted or swung into position? It could even be operated by putting the sidestand of the bike down on a sprung pad...
Thanks for the suggestions,
-- Dave H. (The engineer formerly known as Homeless)
"Rules are for the obedience of fools, and the guidance of wise men" - Douglas Bader