The strong, silent type. The Shimano Alivio RD-M4000 SGS rear derailleur is designed for aggressive riding. With its super low profile and single-tension construction, it does not hit the chainstay in rough riding conditions. It's smooth and quiet, featuring Shadow Rd technology for less trouble.
Braze-on mounting uses fittings permanently mounted to the frame. Collar mounted derailleurs secure around the seat tube with a clamp. Direct mount are fastened to the chainstay.
The maximum number of teeth difference between the smallest and largest chainrings (front derailleur) or cogs (rear derailleur).