My memories of SunRace derailleurs are a little foggy, and I have terrible trouble finding historic SunRace literature - so treat what follows with a touch of scepticism.

I kind-of remember the SunRace 590 as being a cheap, plastic, derailleur found on many of those, how-shall-we-say-it, tacky, inexpensive, no-name, mountain bikes you find in big-box retailers. When I look at it today, I see that it contains very little plastic, and seems rather solidly constructed.

I also remember it as appearing at about the same time as the SunRace 595.

• Derailleur brands: SunRace
• Country: Taiwan
• Date of introduction: 1997?
• Date of this example: unknown
• Model no.: 590
• Weight: 296g
• Maximum cog: 32 teeth? (roughly based on Shimano Deore XT (M739 SGS))
• Total capacity: 38 teeth? (roughly based on Shimano Deore XT (M739 SGS))
• Pulley centre to centre: 87mm
• Index compatibility: 8 speed?
• Chain width: 3/32”
• Logic: top normal
• B pivot: sprung
• P pivot: sprung
• Materials: largely steel with an aluminium b-knuckle and a plastic p-knuckle