For model year 2001 Campagnolo made the following changes to their range:
- A new 10-speed Daytona deraileur was introduced.
- The Racing Triple was rechristened the 'Racing T'. Campagnolo began to group it with Chorus, whereas they had originally grouped it with Athena.
- All the 9-speed derailleurs got a makeover.
So I think that the rear derailleur range might have gone as follows:
- Campagnolo Record (RD00-RE210)
- Campagnolo Record (RD00-RE210L)
- Campagnolo Chorus (RD00-CH210)
- Campagnolo Chorus (RD00-CH210L)
- Campagnolo Daytona (RD01-DA210)*
- Campagnolo Record (RD01-RE209)*
- Campagnolo Chorus (RD01-CH209)*
- Campagnolo Racing T (RD01-RA309)*
- Campagnolo Daytona (RD01-DA209)*
- Campagnolo Daytona Triple (RD01-DA309)*
- Campagnolo Veloce (RD01-VL209)*
- Campagnolo Veloce Triple (RD01-VL309)*
- Campagnolo Mirage (RD01-MI209)*
- Campagnolo Mirage Triple (RD01-MI309)*
* New for model year 2001
From 2000 the part numbers were made up as follows:
- 'RD' for 'rear derailleur' - which was not particularly Italian.
- 2 numbers to indicate the year of introduction. So '01' indicated 2001.
- A dash for good measure
- Two letters that indicated the model/group name. So 'RE' meant Record.
- One number that indicated whether the derailleur was designed for a double chainset ('2') or a triple chainset ('3').
- Two numbers that indicated the number of speeds. So '09' for 9-speed and '10' for 10-speed.
These images come from a pdf downloaded from the Campagnolo web site some years ago. The rear derailleurs are featured from page 15 to page 19.