The Centaur was launched in 1989 as a lower cost alternative to the 1988 Campagnolo Euclid. As far as I can tell the only difference was that the inner parallelogram plate was a steel pressing - which was presumably marginally cheaper than the Euclid's aluminium forging.

I believe that this is a first generation Campagnolo Centaur from 1989 - with no cable adjuster.

This example has the mid-length pulley cage.

Some relevant details are:

• There is a spring adjuster on the p-pivot.
• There is no cable adjuster.
• It has a single parallelogram spring using ~2.0mm wire.
• The inner parallelogram plate is a steel pressing.
• The cable is clamped using a hex nut.
• The pulley wheels are a conventional ball-bearingless design in white.
• The inner pulley cage plate is steel and has a spoke deflector.

• Derailleur brands: Campagnolo
• Categories: Campagnolo - mountain bike madness
• Country: Italy
• Date of introduction: 1989
• Date of this example: unknown
• Model no.: Q010-MD
• Weight: 292g
• Maximum cog: 34 teeth (Campagnolo)
• Total capacity: 38 teeth (Campagnolo)
• Pulley centre to centre: 69mm
• Index compatibility: 8 speed
• Chain width: 3/32
• Logic: top normal
• B pivot: sprung
• P pivot: sprung
• Materials: largely aluminium with a steel inner parallelogram plate and inner pulley cage plate