Originally Posted by MTBMaven

I'm in a similar situation as the OP. Cyccommute, in an earlier post you said a 10 speed road shifter will work with 7,8,9 speed mountain rear derailleurs. Therefore couldn't the OP run the 10 speed 105 brifter with 9 speed derailleur and cassette? Our is it that the index spacing of the 10 speed shifter is designed to work with the spacing on the 10 speed cassette? And that the derailleur is just moving the chain around based on what the shifter tells it.


Big bummer about the 10 speed mountain derailleur not working with road shifters. I picked up a used XT derailleur with hopes of using that with my existing Ultegra 10 speed shifters. I think I might just go with 9 speed barcons, mountain derailleurs and cassette. I have a new Velo Orange triple crankset I plan to use. I can just keep the Ultegra brifters but just use them as a brake lever to save a little coin.

Also investigating ability of 10 speed bacon (Shimano SL-BS79) working with 10 XT rear derailleur.