Starting in 2000, SRAM decided to merge the DI.R.T. designs that they had inherited from Sachs with their own ESP 1:1 actuation designs. Both traditions shared a love of composites and of innovative cable routing.

SRAM decided to go for stiffness with very wide parallelogram plates, something that most derailleur manufacturers have since adopted. SRAM also went for the DI.R.T style straight cable routing. In many ways these derailleurs were the prototypes for the modern classic that is the first generation SRAM X-0.

But there were more than a few flies in the ointment:

• The derailleurs were not light, and, in fact, were heavier than both the Sachs DI.R.T and SRAM's own ESP series.
• In my experience, the composite b-knuckle on the earlier models had a tendency to explode. I found this odd. SRAM were paranoid about b-knuckles exploding - because that was the famous problem with their very first design, the SRAM ESP 900. How did they let this happen again?

• And then there was the look of the beast. It is strangely clunky and uninspiring.

---

This is a rather nice example of a SRAM 9.0SL with a 'medium' pulley cage. Its features are:

• It is conspicuously black and white. A devil to photograph!
• The b-knuckle is composite.
• The inner parallelogram plate is a rather pleasant aluminium item.
• It has a medium, 75mm, pulley cage.
• The pulley cage plates are the later speedier shape.
• The inner pulley cage plate is aluminium.
• The pulley wheels have rather natty sealed bearings.
• The small plate on the inside of the b-knuckle that bears on the gear hanger is made of aluminium.

The eagle-eyed amongst you will note that this 'medium' caged model has a pulley cage 75mm long - exactly the same length as the 'short' caged version. The inner pulley cage plates on the short and medium versions are slightly different, but this seems to be largely a naming change.

The history goes something like this:

• The model year 2000 Dealer Technical Manual and Spare Parts List do not show these derailleurs at all.
• The model year 2001 Dealer Technical Manual shows only a 'short' version, and calls this 'new'.
• The model year 2001 Spare Parts List shows both a 'short' version and a 'long' version.
• The model year 2002 Technical Manual and Spare Parts List both also show a 'short' version and a 'long' version.
• The model year 2003 Spare Parts List, however, shows a 'medium' version and a 'long' version.
• The model year 2003 Technical Manual does not show these derailleurs at all.

---

• Derailleur brands: SRAM
• Categories: SRAM - the X series
• Country: USA, manufactured in Taiwan
• Date of introduction: 2002 for the 2003 model year
• Date of this example: The inner pulley cage plate is labelled 'MAR 23 02', which may mean 23rd March 2002
• Model no.: T500-535-3?
• Weight: 242g
• Maximum cog: 34 teeth
• Total capacity: 37 teeth
• Pulley centre to centre: 75mm
• Index compatibility: 9 & 8 speed
• Chain width: 3/32”
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: Grilon composite knuckles, aluminium parallelogram plates and pulley cage plates.