Just had an off in holyrood park during my standard lunchtime laps. Wasn't even going half the speed I would usually carry through the roundabouts and still lost the front and back wheel on the roundabout by parliament and horse Wynd. Quite a sore off, and smashed my shifter :(
I think it's that "rubber/oil/other crap from cars plus no a bit of rain" thing.
So be careful on the corners out there folks!