- Derailleur brands: SunRace
- Country: Taiwan
- Date of introduction: 2012
- Date of this example: unknown
- Model no.: R91 SD
- Weight: 251g
- Maximum cog: 28 teeth (SunRace)
- Total capacity: 33 teeth (SunRace)
- Pulley centre to centre: 56mm
- Index compatibility: 9 speed (SunRace)
- Chain width: 3/32”
- Logic: top normal
- B pivot: sprung
- P pivot: sprung
- Materials: largely aluminium with a steel inner parallelogram plate and steel pulley cage plates
