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  1. #1
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    SS Stumpjumper tensioning

    Hello there SSers. I have a 2012 carbon stumpjumper single speed and I just recently finished the build. Everything has been great on it so far I just have a few kinks I can't seem to work out. I can't seem to find a sweetspot for my chain tension. I HATE the feeling of a tight chain. In my opinion if the chain isn't dropping, no need to tighten it. It's just extra resistance. That being said, on my new stumpjumper I have to keep the chain really tight or else it will slap my chain stays which I am sure is not ideal for a carbon frame. I tried bringing in the sliders a bit more and taking a link out and that didn't seem to help, am I just gunna have to get a chain stay protector and live with it? Also, My XX1/PF30 single speed crankset setup seems to be pretty damn tight too. It doesn't spin freely at all it seems. Sram recommends the crankset to be tightened to 48-54 n.m. I found an old Schwinn Torque wrench that will go up to 420 sq Inch pounds which is close but not quite 48 n.m. So I tightened my crankset to 420 sq. Inch lbs. I hear some creaking and popping coming out of my drive train since I tightened everything up like this and it seems like there's a lot more resistance than there used to be. I really don't like it. Any suggestions?
    Nature never said one thing, and wisdom another...

  2. #2
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    For the chain tension, consider a half link. Gusset do a good one.

    As for the crank - is the torque wrench still calibrated? Maybe take it in to your LBS and see if you can check it using their torque wrench. Some beer in return should foster good relations

  3. #3
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    It sounds like your crankset has too much preload.

    That said, if you still can't get it going right, you could always move up to a larger chainring / cog combo. It'd get the chain a good bit farther away from the chainstay, and give you more working teeth in the drivetrain.

  4. #4
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    For the chain tension, consider a half link. Gusset do a good one
    I've tried quite a few variations of chain length, none seemed to do better than the others. Also, the Schwinn torque wrench I used I got from the shop. All the Torque wrenches are kept in a secret location that only the manager and the owner are supposed to know about (even though it's in a box in the shelves by the owners desk) hehehe. So I know the torque wrenches are taken care of.

    It sounds like your crankset has too much preload
    I have wondered about this. My XX1 cranks have this pre-load adjustment on it but it doesn't seem to do a whole lot



    As for gearing ideas, I'd really hate to have to take off my XX1 chain ring. The fact that the XX1 crankset came stock with a 32T chain ring was half the selling point for me, lol... Is it tough to find high end 72 bcd chain rings? *starts googling* I suppose Sheldon brown can tell me what other chain ring combos can get me close to 2:1 ratio.
    Nature never said one thing, and wisdom another...

  5. #5
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    Chain Slap: W/O seeing a pic I assume you "may" need to go with a slightly larger cog. If you are hitting the chain stay in the middle going shorter or longer won't make a difference.

    Cranks: You need to loosen your pre-load adjuster until you get play in the cranks and then tighten just enough to take it out. You loosen the small allen screw in the adjuster to adjust and tighten back down so it doesn't slip while riding. IF, you have it unscrewed all the way out and the bottom bracket is still tight then you will need to take one of the thin plastic washer/spacers off the spindle and try again.

    Torque Wrenches: Are often most accurate in the middle range of their scale. It is often not recommended to use torque wrenches near their max or especially their min numbers. That said, if you are getting close to the specified torque with the max setting you should be close or can just give it a "smidge" more.

  6. #6
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    PS. I've found the BB30 and PF30 bottom brackets seem to creak as much or more that the GXP style if not generously greased when installed.

    The schematic in this link shows the spacers "As Needed" that I was referring to above.

    Good Luck!

  7. #7
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    Quote Originally Posted by austinTRON View Post
    I suppose Sheldon brown can tell me what other chain ring combos can get me close to 2:1 ratio.
    Are you kidding?!?!? You really can't do the math? Wow. That's pretty sad. Here, let me do it for you:

    32/16
    34/17
    36/18
    38/19

  8. #8
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    Quote Originally Posted by Thor29 View Post
    Are you kidding?!?!? You really can't do the math? Wow. That's pretty sad. Here, let me do it for you:

    32/16
    34/17
    36/18
    38/19

    I see you lack a sense of humor, how unfortunate for you.


    rideorange52, Thanks for the input, I'm gunna spend my day off messing with my preload and spacers. I guess I'll have to spend my day off back at the shop where I have access to that old torque wrench. sux. :/
    Nature never said one thing, and wisdom another...

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