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Thread: Custom double

  1. #1
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    Custom double

    Hi guys, hope I can get some clarification on some things I have been pondering. Background: I am extremely old school. My bike is a 1998 model year and the last time I completely overhauled the componentry, I installed a 3x9, standard 22-32-44 w/11-32 on the 26 inch bike. I want a 29er for my next bike, and while I have no problem with installing another triple, I'd prefer a double because I don't want so many redundant gears, and on a 29er with a 44 ring and 11 cog, that is just absurdly long, so I can do without so much top end.

    I like the range of the 3x9. I am extremely old school in riding philosophy as well. I just want one bike and I want to go everywhere and do everything with it. I have a use for every ratio on the old 3x9 range, whether its doing a downhill road portion or a brutal grade at the end of the 5th or 6th hour of a massive ride, so I don't really want to sacrifice on range. I did the calculations. To cover the range of a 3x9 11-32 26er on a 29er with a 11-36 cassette, I need a 22-39 double. That is just a bit wider than the current double configurations on the market.

    So...can I buy a regular double and just replace one of the rings with the appropriate BCD in my ratio of choice to achieve my "custom double"? Would there be any issues, mechanical or otherwise, with that?

    edit - hypothetically, if I got something like a Sram 2x10 36-22 (64/104), can I just swap the 36t x 104 out for any one of the numerous 38t x 104mm rings out there, or even a touch bigger like a 40t if I want?
    Last edited by NA1NSXR; 04-22-2013 at 12:55 AM.

  2. #2
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    Theoretically, yes you could do that. However, you will not likely have chainstay clearance for that large of a ring in the middle position.
    Many 29ers will barely clear the normal 32 in the middle position.
    It may shift like crap but you never know.
    You would have to shift up through 5 gears on the 22 before you shifted up to the 39 - and you would need to down shift the 5 rear gears at the same time.

  3. #3
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    Re: Custom double

    Not many front derailleurs can handle a 17t difference...

  4. #4
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    I see the FD capacity for these Sram 2x10's are 15t....thanks for the reminder.

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