I'm building up a Rocky Mountain Sherpa frame this winter and have settled on a drivetrain, but I thought I'd let the forum validate my assumptions. The Sherpa is a touring frame with large tire clearances and I'm building it up more as a gravel grinder. It has a 68 mm wide bottom bracket shell and 135 mm rear hub spacing. The seat tube (Reynolds 853!) is 28.6 mm outside diameter.
The drivetrain I'm considering will consist of:
- Shimano FC-M785 28/40 front crankset with external BB cups
- Shimano FD-M785 front derailleur
- Shimano HG-50 11-34 9-spd freewheel
- Shimano RD-M580 low normal rear derailleur
- Dia Compe silver bar end shifters
- Wipperman Connex 908 or KMC 9-spd chain
This should give me gearing from 22-99", about right for my neighborhood, which has some significant hills. The M785 crankset is a true mountain double (not a 2+bash) with a chainline of 48.5 mm. I'm sticking with 9-speed chains and cassettes for cost and durability for now.
Yes, I looked at SRAM 2x10, but apparently the SRAM derailleur won't work with the Dia Compe bar ends (according to Rivendell). The bar ends don't work with Shadow RD either. I looked at brifters (this is a drop-bar bike) but I don't care to spend $$$ when the brifters inevitably wear out. I already have another bike for that.
The low-normal RD lets the bar ends work logically - levers up for higher gears, levers down for lower gears on both front and rear.
Thoughts? Do I have the proper chainline? Will the FD shift correctly?