Derailer - Rear - Shimano Deore (model M591), black

 For wide range gearing—like for touring or trail riding.

This is a good old rear derailleur that'll never let you down. The Deore was introduced in about 1985, and there have been probably 15 variants, all "Deore" since then. It's Shimano's M.O. All of them have worked well, no surprise, since the Deore is a Shimano derailer after all, and it is in the upper chambers of the derailer line, and is arguably -- and we'd argue it --- the best value.

Shifts to 36t.  For friction shifting or 9 speed drivetrains.  An excellent choice, always. Nobody, but nobody, ever squawks about a Deore. 

Shimano code name RD M591 SGS

MADE IN JAPAN

---------Feb 4, 2020 NOTE:

These were available in silver but Shimano decided to stop making those - drat...  These black M591 derailleurs will also go away forever, supposedly sometime later this year, unfortunately.