After the disastrous recall of every single one of its first model of derailleur (the SRAM ESP 900), SRAM boldly stuck with its dream, slightly redesigning the gear and sorting out the manufacturing process - and the 1996 SRAM ESP 9.0 and then the 1997 SRAM ESP9.0SL were the results.
The design of the 9.0SL includes all SRAM’s signature features; the one-to-one actuation, the steeply angled slant parallelogram, the lack of float in the guide pulley and the single sprung pivot design with the top pulley wheel concentric (or, later, almost concentric) with the sprung pivot (all except one-to-one actuation and that 'almost' follow the basic design of the SunTour V GT).
When manufactured using ‘carbon composites’, with sealed bearing pulleys and an aluminium attachment bolt, the result was an extremely light and very capable gear. However, I personally still found it hard to believe that a plastic gear had the integrity of an aluminium design, and I found it hard to shake the unfair notion that this gear was a sophisticated toy.
A simplistic, but OK, way of dating the SRAM 9.0 SL is to look at the logos:
Some key features of this interesting, mid-period, example, with its mid-length pulley cage, include:
Note that, although the cage plates are shorter and both are composite, the whole derailleur is not noticeably lighter than the long cage versions. How did that happen?