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  1. #1
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    20 tooth grannies?

    Today I climbed up Mt. Tamalpais on my 3x9 Karate Monkey. I'm running a regular Shimano LX triple in front and a SRAM 11-32 in back*. The 22-32 worked on almost everything...

    So, who's running a 20 tooth granny?
    What kind is it? Where'd you get it?
    What kind would you rather have?
    What kind of crank do you run it on?

    edit 1:
    * I forgot to mention that I tried to run an 11-34 cassette on this frame, but found that there wasn't enough space between the 34 and the upper derailer pulley (on my shimano XT M750). The derailer hanger on a KM is not very far from the rear axle, and doesn't seem to offer as much space for large cogs...
    Last edited by beanfink; 10-17-2007 at 08:14 PM.

  2. #2
    Former Bike Wrench
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    20 tooth is available in the old 5 bolt compact 58/94 pattern. The newer 4 bolt 64/104 cannot go smaller than 22 tooth as the bolt pattern is too large for a 20 tooth.

    Have you considered going to a 11-34 in the back?

  3. #3
    R.I.P. DogFriend
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    There are 4 bolt 20t chainrings available.

    The company is called action-tec.

    Check this out::

    Action Tec 20t Granny?

    and this:

    http://www.actiontec.us/index.htm

    http://www.actiontec.us/prices.htm
    Last edited by jeffj; 10-17-2007 at 08:36 PM.

  4. #4
    R.I.P. DogFriend
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    Quote Originally Posted by beanfink
    Today I climbed up Mt. Tamalpais on my 3x9 Karate Monkey. I'm running a regular Shimano LX triple in front and a SRAM 11-32 in back*. The 22-32 worked on almost everything...

    So, who's running a 20 tooth granny?

    I am.

    What kind is it?

    Race Face 5 bolt steel

    Where'd you get it?

    Found it on a bargain table when Cambria briefly had a shop on PCH in Redondo Beach. Cost me $5.

    What kind would you rather have?

    I don't know that I'd rather have another kind. This one is a lifesaver... er, lungsaver.... um, I mean legsaver

    What kind of crank do you run it on?

    Race Face Turbine - 5 bolt square taper

    There you have it.

  5. #5
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    So you either have to get a squarish 20 tooth (which seems like would defeat the purpose as the gear ratio would constantly be changing) or you have to break out the dremel to fit a round 20 tooth on a 4 bolt crankset.

    Not exactly a strait forward product...though doable

  6. #6
    Captain Underpants
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    Quote Originally Posted by mtnbiker72
    20 tooth is available in the old 5 bolt compact 58/94 pattern. The newer 4 bolt 64/104 cannot go smaller than 22 tooth as the bolt pattern is too large for a 20 tooth.

    Have you considered going to a 11-34 in the back?
    Ha.

    I am running a 20t Ti ActionTec on an XT (104 bcd I think?) crankset. Works fine. Perfect for Tam. got it from Universal.

    You can order one from Boone as well, as long as you don't mind the 4 month wait.

    I take mine up Burdell all the time.

    All you naysayers and internet armchair theorists are SMOKING CRACK.

  7. #7
    RHRF!
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    Not True...

    Quote Originally Posted by mtnbiker72
    So you either have to get a squarish 20 tooth (which seems like would defeat the purpose as the gear ratio would constantly be changing) or you have to break out the dremel to fit a round 20 tooth on a 4 bolt crankset.

    Not exactly a strait forward product...though doable
    ...I've been running a Boone 20t Ti granny (no 'dremel' mods) on my RaceFace Deus 4-bolt crank for 2 years now. It's just as round as a 22t, only smaller...

    BTW...I'm a 230lb clyde and I use the 20t in conjunction with an 11-34 cassette without any rear derailleur (Sram X.9) pulley rubbing.
    "The secret of joy is the mastery of pain." (Anaïs Nin)

  8. #8
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    So, who's running a 20 tooth granny?

    Running 20t-30t on my RIP9 with an 11-34 cassette

    What kind is it? Where'd you get it?

    Salsa 5bolt 20t that I picked up from Cambria

    What kind would you rather have?

    I like the 20t chainring. I'm going to add a 36t cog to the cassette in the spring. I'll drop the 11t cog and run 12-36.

    What kind of crank do you run it on?

    190mm Profile Racing

  9. #9
    NMBP
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    I read somewhere here on MTBR of someone using spacers on their XT crank instead of Dremeling the stand offs.
    Riding Fat and still just as fast as I never was.

  10. #10
    pedal pusher
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    I run a 5-bolt 20T grannie on my Race Face LP. There's nothing too steep to climb with it. You can still buy them at JensonUSA, I believe.

  11. #11
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    Another option

    Replace the beta-adjustment screw on your derailleur with a longer one. It'll allow you to move the top pulley farther away from the bog cog allowing the use of your 11-34 tooth cassette. 2 teeth in the back is a bigger gear ratio change than 2 teeth in the front...it'll be much cheaper for you too.

  12. #12
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    Quote Originally Posted by Nater
    Replace the beta-adjustment screw on your derailleur with a longer one. It'll allow you to move the top pulley farther away from the bog cog allowing the use of your 11-34 tooth cassette. 2 teeth in the back is a bigger gear ratio change than 2 teeth in the front...it'll be much cheaper for you too.
    By my math, 2 teeth in the front makes a bigger difference, and gives a lower ratio...

    22/34=.647
    20/34=.588
    Diff=.059

    22/34=.647
    22/36=.611
    Diff=.036

    A 22/38=.578 would be slightly lower than the 20/34=.588, but 4 teeth larger.

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