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Thread: torque specs???

  1. #1
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    torque specs???

    Now that we have CF bikes in the corral need some help. My speciazed roubaix specs decal came off seat tube. Just bought my wife a trek 4.5 wsd with no decals and my soon to be 12 yr old son has a trek 5 series wsd that is all carbon. Im a nervous nelly when it cmes to tighening things up. Ive done some research but finding general ranges. Seat post? CF stem to CF bars and CF fork? My son growing and know adjustments will be frequent this year.

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    Google carbon torque specs or in your case Trek torque specs
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  3. #3
    Senior Member rydabent's Avatar
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    Due to the tenderness of CF frames, there is no doubt that torque wrenches should be used. Stay away from the "gods gift to the cycling world" mechanic that says he can torque things properly "by feel".

    As a tech specialist engineer, I had to follow or assist any number of techs that just knew "by feel" they were adjusting something right. They pretty much ruined hundreds of thousands of dollars of assemblies when they adjusted them by feel rather than using torque wrenches and proper tools.

    I know that I will get grief from some of these old time wonderful mechanics, but right is right, and anything else is just a guess depending on how that mechanic felt on a given day.

  4. #4
    Andrew R Stewart Andrew R Stewart's Avatar
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    Also remember that stated torque levels are max amounts. If the component stays put with less tightening then stop there. Application of a "carbon prep" will help to allow clampings get a better bite. Andy.

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    Quote Originally Posted by rydabent View Post
    I know that I will get grief from some of these old time wonderful mechanics, but right is right, and anything else is just a guess depending on how that mechanic felt on a given day.
    When it comes to CF I doubt you will get any grief. We've been around enough to know that things have changed drastically over the years, and it's not hard to understand that carbon is a whole different animal. Same goes for some components whose design has completely changed, so that fasteners are in a more torque-sensitive arrangement.
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  6. #6
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    OP, I doubt you have any ultra-light carbon stuff like handlebars, but you have to take the torque recommendations with a grain of salt. In other words be even more careful than the torque recommendation suggests. I had a Kestrel handlebar that said use the stem maker's recommendation for torque. That was 6 Nm. The bar cracked at around 4. Guess what? The replacement of the same model is plenty tight at 2. So really use the recommendations as an absolute upper limit. You will rarely need to go that high.
    Robert

    "Wish I didn't know now what I didn't know then." (Bob Seger, "Against the Wind")

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    Buy a Richey Torque key at about 4-5 Nm, should be perfect for basically all the standard carbon bits.

  8. #8
    Senior Member blacknbluebikes's Avatar
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    Given the question, you'll likely get many dividends from this book, including a "torque table" for points all over the bike:
    http://www.parktool.com/product/big-...-edition-BBB-3

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