There used to be a track just south of here with really deep ruts, and when i first started green laning i used to see the "bike" track between the two ruts and marvel at the skill of the riders that could follow it without dropping into the ruts.
I tried and tried to stay on the little track with varied success, especially as the other riders had managed to follow it even over some real dodgy cambers, it was a while before i realised that it was a mark caused by the diff cases of the farmers 4x4