A strong match for MTB riders replacing a 10- or 11-speed rear derailleur on a rough-trail bike, particularly those using a 1x10, 2x10 or 2x11 setup.
The Shimano Deore RD-M5120-SGS is an MTB rear derailleur built for 1x10, 2x10 and 2x11-speed drivetrains. It suits trail bikes running a wide-range cassette, with capacity for a 46T low sprocket in 1x10 setups or 42T in 2x10 and 2x11 setups. Check your shifter, cassette and chain configuration against these limits before ordering.
For rough and technical riding, the SHIMANO SHADOW RD+ chain stabiliser helps reduce chain drop, chain slap and drivetrain noise. That gives you a quieter, more controlled drivetrain when the trail gets rough, while the reduced tension in low gear helps the derailleur and chain operate with less strain.
The low-profile design keeps the derailleur tucked in to help avoid rock damage, making it a sensible replacement or upgrade for riders who regularly ride rocky trails. With an SGS cage, 11T pulleys and compatibility with HG-X11 and HG-X 10-speed chains, it is a straightforward option for reliable everyday MTB shifting.
Wide drivetrain compatibility
Designed for 1x10, 2x10 and 2x11-speed MTB drivetrains, giving you flexibility when replacing an existing derailleur.
SHADOW RD+ stabiliser
Helps reduce chain drop, chain slap and drivetrain noise for more controlled shifting over rough terrain.
Wide-range cassette support
Handles up to a 46T low sprocket in 1x10 configurations, or 42T with 2x10 and 2x11 setups.
Low-profile shape
Keeps the derailleur more tucked away from rocks and other trail hazards.
SGS long cage
The long-cage format suits the listed wide-range MTB configurations and supports a 10T maximum front difference.
11T pulley wheels
The 11T pulley specification supports smooth, dependable derailleur operation.
HG-X chain compatibility
Compatible with HG-X11 and HG-X 10-speed chains for the published drivetrain applications.
General
Compatibility
Features
SHIMANO SHADOW RD+
The rear derailleur stabiliser reduces chain slap and helps prevent chain drop, giving you a quieter, more controlled drivetrain. The design is lighter and more efficient than a roller-type chain device.
Shimano is a Japanese component brand founded in 1921 in Sakai, Osaka. The company began with bicycle component manufacturing and has grown into a global business focused on bicycle components, fishing tackle and rowing equipment, while keeping its headquarters in Sakai.
In cycling, Shimano is best known for building complete component ecosystems that span road, mountain, gravel, commuting and e-bike use. Its range covers drivetrains, brakes, wheels, pedals, shoes and related parts, and the brand has had a long presence in Australia through a local business established in Sydney in 1992.
