SRAM road and mountain mix?
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  1. #1
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    SRAM road and mountain mix?

    Does anyone have the numbers for how much cable is pulled with each shift with SRAM road stuff? Correspondingly, how much cable is pulled for each shift with a 1:1 mountain shifter? My idea is to pair an X.0 derailleur and 11-34 9-speed or IRD 11-34 10-speed cassette with Force shifters.

    This is for my cyclocross bike and my big goal for the season is Iron Cross which covers 62 miles and 6500 feet of climbing. Even with straight Force components, a 34x28 low gear is too high for some of the climbs. Last year my low gear was a 36x34 and I still walked a few steep climbs.
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  2. #2
    Roadie with unshaven legs
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    According to this website the SRAM 1.0 derailleur has a 1.1 shift ratio, meaning that for every 1mm of cable pulled the cage moves over 1.1mm.

    I have surmised that a SRAM road rear derailleur has a similar derailleur shift ratio as a pre-2001 Campagnolo derailleur of 1.4 (a Campy 10-speed shifter will shift an older Campy rear derailleur across a Shimano 10-speed cassette just fine, just as a 10-speed Campy shifter is reportedly able to do with a SRAM road rear derailleur). The SRAM road shifters should pull about 2.8mm per shift according to the website I linked above.

    Using this info you should be able to calculate the amount that the rear cage will move over per shift: 2.8 X 1.1 gives you 3.08mm per shift. Shimano's spacing for their 10-speed cassettes (that SRAM uses) is 3.95mm so this should not work. You may be able to figure out alternate mounting positions on the rear derailleur bolt that may or may not correct this issue for you.

    I would go with a Shimano mountain rear derailleur with a Shimano brifter. If this isn't something you want to do because you are anti-Shimano or something then you can try looking at that site I linked to see what alternative mixes you can try.

  3. #3
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    It won't work.

    Apparently the Mountain stuff while close isn't actually 1:1 like the road stuff is. I was gonna run an XO rear with Red levers and SRAM told me it woudn't work...

  4. #4
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    didn't contador use and x.0 rd in the tt in the giro?

  5. #5
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    I took some measurements of my own. It would appear that a SRAM X.O derailleur requires 34mm of cable pull to shift through the cassette. At 8 intervals, that's 4.25mm per shift. A SRAM Force rear derailleur requires 25.5mm of cable pull to cover the full range. At 9 intervals that's 2.83mm per shift.

    In conclusion I would need to somehow increase the cable pull ratio by a factor of exactly 1.5 to use a Force shifter with an X.0 rear derailleur.

    Does anyone know of a product like the Jtek shiftmate or Problem Solvers travel agent that has this ratio?
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  6. #6
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    So sad, im planning to get the 09 Rival shifters on X9 RD(i have it in my stash) ..

  7. #7
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    Does shiftmate make a model that would work? Also, how about one of the 10 speed wide range cassettes? Sure, it's really too big of a cog..... but if you don't cross chain you can get it to work. Especially if you use a 32 as the largest cog. You can even drop the small ring size a bit.

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