Originally Posted by TimothyH

I have not upgraded but will as soon as I find a source for the 8050 GS rear derailleur. My understanding is as follows:

The 8050 rear derailleurs come with the bracket installed which allows them to be used with a traditional derailleur hanger. An upgrade from 6870 to 8050 does not require that the derailleur hanger be changed. Just take off the 6870, bolt on the 8050, connect the wire, install the chain, adjust and ride.

To use the 8050 rear derailleur on a bike which has direct mount built into the frame or attached to the rear dropout then the above mentioned bracket is removed from the derailleur using a 5 mm hex wrench. The derailleur is then bolted to the frame or bracket on the frame.

Reference http://si.shimano.com/pdfs/dm/DM-R8050-02-ENG.pdf. See page 45.

I'm open to correction but this is my understanding.


-Tim-