short cage mech with granny?

brutaldeluxe09
brutaldeluxe09 Posts: 96
edited May 2011 in MTB workshop & tech
I'm looking at being able to adapt my current single ring 34T with 11-34 cassette to a dual ring with either 11-32 or 11-34 cassette but know that I am going to run into trouble as I have a short cage mech.

I've read around the previous posts and found this as a calculation:
Max capacity of SRAM
Long - 45T
Med - 37T
Short - 30T

Capacity needed = (biggest chainring - smallest chainring) + (biggest sprocket - smallest sprocket)

On this basis I have worked out that if I have an 11-32 cassette I would need a 26T granny to get this working OK to be still be able to use all gears.

Is there such thing as a 26T granny and if so what complications, if any would this bring?

Comments

  • nicklouse
    nicklouse Posts: 50,675
    yes you can get 26 and 28T to fit 64mm 4 bolt BCD cranks.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • nice don't see the need for anything less than 26T anyway, will try 28T first I reckon.