This derailleur was brought to my attention by Gerrard from London, who describes himself as 'obsessive - even for a nerd'. He read about my interest in fake Campagnolo Gran Sport derailleurs and he is convinced that this derailleur should be added to my list of counterfeits. His evidence is as follows:

• The lettering on the outer parallelogram plate is spectacularly bad. The characters are thick, misshapen and uneven. In the words 'Gran Sport' the enclosed areas in the 'A' and the 'P' are almost completely filled in. A bored five year old with a wax crayon could do better.
• If the lettering is bad, the background is even worse, with significant bald areas amongst the derisory smattering of poorly resolved dots.
• The 'lump', on the p-knuckle, that holds the pulley cage stop screw, is weirdly misshapen. It has one flat side and an odd curve on the other. On other Gran Sports this bulge is symmetrical and smoothly curved.
• The p-knuckle has a sizable piece of molding 'flash' just adjacent to this bulge. On other Gran Sports any molding flash has been carefully ground off and polished out.
• Chrome has flaked off in large chunks, implying that it has not been applied after the correct etching and pre-plating procedures (who do they think they are? Ducati?). Gerrard was particularly exercised by the head of the bolt that holds the parallelogram spring, which has blistered chrome all over it. In his experience (and mine) these bolts are usually impeccably chromed.

This is just the kind of stuff that I love! And if you're reading this web site, it is probably just the kind of stuff that you love too.

My take on this derailleur is that, although admittedly very odd, it is most likely to be a genuine Campagnolo product. My most convincing evidence for this is that it weighs exactly the same 291g as my other 1956 version of the Gran Sport. If you are starting from scratch, it is very difficult to make a copy that comes in at precisely the same weight.

However, I would note that, in 1956, the Campagnolo Gran Sport was the most technically advanced, most prestigious, most desirable and possibly the most expensive derailleur in the world. It was marketed as being a product of unparalleled Italian engineering and craftmanship. It is, therefore, more than a little alarming that this example, with its awful plating and bad, misshapen, blobby, sloppily-finished, castings, had slipped past the eagle eyes of Campagnolo's famously quality-obsessed artisans. But a bottle of Barolo at lunchtime can do that.

My thanks go to Gerrard for his relentless detective work.

• Derailleur brands: Campagnolo - I think!
• Categories: Campagnolo - the good stuff
• Country: Italy
• Date of introduction: 1956
• Date of this example: unknown
• Model no.: 1012
• Weight: 291g
• Maximum cog: 26 teeth (stamped on the inner parallelogram plate). Note that various versions of Sutherlands quote various, often much larger, figures.
• Total capacity: 18 teeth? (this is from bike shop folklore only). Again note that various versions of Sutherlands quote various, often much larger, figures.
• Pulley centre to centre: 43mm
• Index compatibility: friction
• Chain width: 3/32
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: bronze knuckles, steel parallelogram plates, steel pulley cage plates and steel pulleys