V-Max motor converted to Chain by the look of it. There used to be a couple of kits available off the shelf to do it as the standard shaft really restricts the width of rear wheel/tyre you can use.
Although.... for the results to be consistent & comparable, I'd have thought each time the bike was pushed they would have to ensure they weren't imparting a left/right bias to it, the front wheel was pointing in exactly the same direction and the bicycle itself wasn't leaning to the left or right. Pedals would also have to be the same position to ensure consistent weight distribution. Otherwise the lines are just showing the distribution (of the results) of these variances. As you could imagine I go down a storm at parties... I'll get me coat
2 x images of ex-Southern Railway Class M7 0-4-4T No.672 photographed upside down after falling down the Armstrong Lift Shaft on the Waterloo & City Line at Waterloo Station on the 13th April 1948... The incident occurred because the platform supports were not properly engaged while coal wagons were being loaded onto the lift, causing the platform to tilt and the locomotive to fall. The locomotive and wagons were cut up on-site as there was no feasible way to retrieve them...
