The Shimano Alivio RD-M3100 SGS Rear Derailleur is designed for dependable 9-speed shifting on compatible mountain bike drivetrains. Built as part of Shimano’s Alivio M3100 series, it combines smooth gear changes, wide-range cassette compatibility, and a low-profile design suited to MTB, trail, recreational, and everyday riding.

Its SHIMANO SHADOW design positions the derailleur closer to the frame, helping reduce exposure to impacts and obstacles while improving drivetrain stability. This compact profile makes it particularly useful for riders who regularly encounter rough terrain or technical sections.

The SGS long-cage configuration supports wider gearing and works with a maximum low sprocket size of 36T, giving riders useful range for climbing and mixed terrain. The 11T pulleys help guide the chain smoothly through the drivetrain and support consistent shifting performance.

An integrated barrel adjuster allows quick cable tension fine-tuning, making setup and routine adjustment easier. This helps riders maintain accurate shifting as cables settle or wear over time.

The Shimano Alivio RD-M3100 SGS is a practical upgrade or replacement option for compatible 9-speed MTB systems, offering a reliable combination of shifting performance, durability, and easy adjustability.

Features

• Designed for Shimano 9-speed MTB drivetrains

• SHIMANO SHADOW low-profile construction

• SGS long-cage design

• Smooth and reliable gear shifting

• Helps reduce derailleur exposure to trail impacts

• Integrated barrel adjuster for easy tuning

• Supports maximum low sprocket up to 36T

• 11T pulley system

• Suitable for MTB, trail, recreational, and everyday riding

Specifications

Brand: Shimano

Series: Alivio M3100

Model: RD-M3100 SGS

Product Type: Rear Derailleur

Speed: 9-Speed

Cage Type: SGS / Long Cage

Technology: SHIMANO SHADOW

Pulley Size: 11T

Maximum Low Sprocket: 36T

Minimum Low Sprocket: 32T

Maximum Top Sprocket: 12T

Minimum Top Sprocket: 11T

Adjustment: Barrel Adjuster