In article ,
says...
http://www.gettyimages.com/detail/51...Hulton-Archive

The wierd thing about that picture, in my opinion, is that the bike
doesn't aoppear to be properly balanced. The contact point with the
chap's head is well back from the 'bottom' of the wheel. Unless th
ewheel is somehow locked from rotation I would have thought it would
immediately roll backwards down his forehead. Was there something in the
bike design that stopped the wheel rotating backwards perhaps?

Mike