The title is the utter b*ll*cks (IMO) told to my son. Personally, I think the chain kept coming off because it was slack - I could put it back on the cogs without loosening the wheel, just with my fingers.
Unfortunately, my son believes said 'frame builder' (I'd like to know who they are, haven't heard of any frame builders in York since the old chap who had a shop on Clarence st retired), and stomped off in a rage when I informed him that the chain was coming off because it was slack. The chain was slack because someone built the bike with security skewers and didn't supply the required tool.
