Is is one of of only 2 known examples of this highly unconventional frame.It was British builder.it was built with the intention of correcting chainline issues, allowing the chainring to move from side to side, for adjusting the chainline.The chainring is adjusted with a modified Cyclo Benelux rear derailleur that is affixed to it.I guess … Continue reading 1957 Elswick Hopper Vampire Convincable