Trail and cross-country riders on a 1x12 Shimano mountain bike drivetrain who need a replacement or upgrade rear derailleur.
The Shimano Deore RD-M6100-SGS is a long-cage rear derailleur for 1x12-speed mountain bike drivetrains. It handles cassettes from 10T up to 51T with a 41T total capacity, and it is made for a single chainring up front.
SHIMANO SHADOW RD+ is the built-in chain stabiliser, which Shimano says reduces chain drop, slap and noise. Larger 13T pulleys help with efficiency and chain management, and the low-profile shape helps the derailleur avoid damage from rocks.
SHADOW RD+ stabiliser
Shimano's built-in chain stabiliser reduces chain slap and helps stop the chain dropping on rough ground.
Long cage, 10 to 51T
Handles 12-speed cassettes up to 51T, with a 41T total capacity.
13T pulleys
Larger pulleys that Shimano says increase efficiency and chain management.
Low-profile design
A tucked-in shape that helps avoid damage from rocks.
Drivetrain fit
Construction
SHIMANO SHADOW RD+
A rear derailleur stabiliser that reduces chain slap and gives a simple answer to chain drop. Shimano says it is lighter and more efficient than a roller-type chain device.
Great for
Maybe not for
Long cage (SGS): largest sprocket 51T, smallest 10T, total capacity 41T, single chainring only. Use it with an HG 12-speed chain and a 12-speed cassette. It fits conventional direct-attachment and UDH derailleur hangers.
Use the lever switch properly
Shimano's manual says to move the lever switch to OFF before you take the rear wheel out, and it recommends leaving the switch ON while riding to reduce chain slap and help keep the chain on the sprockets. Check the plate unit cover and its cap are fitted before every ride, and do not take the derailleur apart or modify it, as you may fall and be seriously injured. Keep rust cleaners away from the chain, because alkali or acid based solvents can make a chain break.
