1990s Shimano Acera X Rear Derailleur RD-M290 Long Cage SIS Mountain 7 Speed
Original Shimano Acera X RD-M290 rear derailleur from the 1990s, correct for classic MTB and hybrid builds running 7-speed SIS indexing. This is the long cage version, designed to handle wider gear ranges common to triple crank setups of the era.
Stamped “RD-M290 / Shimano / Japan VIA”, confirming authentic Shimano production. Features the Acera X graphic, alloy body, steel cage plates, and Shimano’s proven SIS actuation. A solid, dependable derailleur from Shimano’s golden-era MTB component lineup.
Ideal for period-correct restorations or riders maintaining a reliable vintage drivetrain.
Brand: Shimano
Model: Acera X
Model Number: RD-M290
Era: 1990s
Speed: 7-Speed
Cage Length: Long Cage
Shifting System: SIS
Mount: Standard hanger mount
Material: Alloy body / steel cage
Made In: Japan (VIA stamped)
Application: Mountain / Hybrid
Used, vintage condition.
Normal cosmetic wear from age and use
Pulleys spin freely
Cage is straight with no cracks or bends
Mounting threads clean
Spring tension feels good
Please review all photos carefully—they are part of the description.
The Acera X RD-M290 sits in a sweet spot of Shimano history—durable, serviceable, and designed before cost-cutting became the norm. These derailleurs shift smoothly, hold adjustment well, and are increasingly hard to find in clean, complete condition for accurate 1990s MTB builds.
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