The Nivex derailleur is an aesthetically ugly, but mechanically beautiful, thing. Its looks are a chaotic blend of baroque curves and medieval axe-heads, but, mechanically, it is arguably the first true parallelogram mechanism to reach series production.

By mounting the parallelogram under the chainstay the Nivex maintained a reasonably constant chain gap. A small pivoting arm holding the end of the p-pivot spring maintains a reasonably constant chain tension. It is a twin cable, unsprung device - a configuration which is hard to set up, but, when adjusted well, gives a pin-sharp, light-touch feel.

All in all it is one of the great designs of derailleur history.

I am vaguely aware of several variations of the Nivex:

• At every stage there was a braze-on version and clamp-on version.
• The initial version (1938?) had a 54mm pulley cage. This version was sometimes referred to as 'course' or 'Grand Sport'.
• Very shortly after that (1939?) a longer pulley cage version was introduced. I have been told that this had a 75mm long pulley cage - but I never measured one. The version was referred to as being for 'cyclotourisme'.
• After the Second World War (1951?) the long pulley cage version got 'improved' with a tension pulley with large aluminium flanges.

This is a well used, but decent, example of a braze-on, short pulley cage, 'course' or 'Grand Sport', Nivex.

• Derailleur brands: Nivex
• Country: France
• Date of introduction: 1938?
• Date of this example: unknown
• Model no.: unknown
• Weight: 245g including fixing bolt
• Maximum cog: 30 teeth?
• Total capacity: 16 teeth
• Pulley centre to centre: 54mm
• Index compatibility: friction
• Chain width: 3/32”
• Logic: none - the paralellogram is unsprung
• B pivot: none
• P pivot: sprung
• Materials: steel

Ref. 2261