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  1. #1
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    Headset won't stay tight





    Hey everyone, I'm having an issue with the headset on my CAAD12. I tightened it last night just before taking it into work this morning. Everything checked out. I even pulled the compression plug and re torqued that to 4 nm, set the stem bolts to 5 nm after tightening the plug. Today after getting home from work, my cone spacer is freely spinning again, and I can feel a tiny bit of play when I hold the brake and shake the bike forward. I've got carbon paste between my stem an steerer. I'm terrified to overtighten my steerer.
    What am I doing wrong or missing?

  2. #2
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    Stick a ruler down the steerer and measure the distance from the end of the steerer to the top of the compression plug. Remember that number.

    Repeat your adjustments then ride the bike until your problem reappears. Remeasure and see if the compression plug is creeping up the steerer.

  3. #3
    'brifter' is a lame word.
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    4nm sounds like not enough for the compression plug. Are you sure that's the correct torque? I'm betting the plug is slipping up. You don't even have to measure anything...if it loosens up again just pull the stem off and look. Takes 20 seconds.
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  4. #4
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    Quote Originally Posted by cxwrench View Post
    4nm sounds like not enough for the compression plug. Are you sure that's the correct torque? I'm betting the plug is slipping up. You don't even have to measure anything...if it loosens up again just pull the stem off and look. Takes 20 seconds.
    I stopped there because I haven't been able to find any torque spec for the compression plug.
    Does 5nm like the stem sound good?

    Sent from my SM-N950U using Tapatalk

  5. #5
    'brifter' is a lame word.
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    Quote Originally Posted by evan326 View Post
    I stopped there because I haven't been able to find any torque spec for the compression plug.
    Does 5nm like the stem sound good?

    Sent from my SM-N950U using Tapatalk
    A lot of them are 8-10nm. Find the spec.
    I work for some bike racers
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  6. #6
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    Headset won't stay tight

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    Last edited by Opus51569; 2 Weeks Ago at 04:15 AM.
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  7. #7
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    I hate cannondale compression plugs. I was having issues with mine too until I got rid of it. I installed a nice long one with a different basic top cap and problem solved.
    use a torque wrench

  8. #8
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    Quote Originally Posted by cxwrench View Post
    A lot of them are 8-10nm. Find the spec.
    Looks like it is 4nm Mountain Bikes, Road Bikes, eBikes - Cannondale Bicycles
    Page 99 of the owners manual.

  9. #9
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    I'm having trouble understanding how the compression plug is impacting the headset tightness. To me, it's in there for making the initial adjustment and to support the carbon steerer under the stem, but once the stem bolts are torqued to spec, how can the headset loosen?

  10. #10
    'brifter' is a lame word.
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    Quote Originally Posted by GKSki View Post
    I'm having trouble understanding how the compression plug is impacting the headset tightness. To me, it's in there for making the initial adjustment and to support the carbon steerer under the stem, but once the stem bolts are torqued to spec, how can the headset loosen?
    It happens all the time. It works a lot like a Shimano crank...the top cap and bolt back up the stem bolts. If the expander is loose or just sucks there is easily enough leverage in the stem/bars to wiggle it loose. What happens a lot is the expander will creep up and the headset gets loose...then someone tries to tighten the headset but there is no gap cuz the expander is higher than it should be. Huh...that's weird...throw another spacer in there w/o checking the expander. It creeps some more, same thing happens. All the time.
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  11. #11
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    The particular problem I had with this compression plug in question is that the top cap portion of the plug, which is integrated, didn't have a large enough diameter to cover the top of the stem. It could basically get wedged inside of the stem and the stem could creep up around it by a fraction of a mm.

    And in addition to the fail integrated top cap that didn't hold right and could never be lined up perfect, it didn't support the steerer fully and correctly. I'm pretty sure it's one of the one's Raoul highlighted as a poor design.

    It's crap like this SI plug from cannondale that made me decide long ago to stop trusting manufacturers with the safety of my steerer tubes (aka my teeth or life), and to start using proper compression plugs that were fully supportive on all of my bikes. I even decided against the system 3T/Cervelo uses where you're supposed to epoxy in your own alloy sleeve after cutting the steerer and use a star nut.

    https://www.ebay.com/itm/Carbon-Fork...cAAOSwU-pXtfUh

    Problem solved for less than $10, and if you install it and use it right it will properly protect your steerer (teeth).
    use a torque wrench

  12. #12
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    Quote Originally Posted by cxwrench View Post
    A lot of them are 8-10nm. Find the spec.
    8-10nm on a carbon steerer?? Not saying you're wrong, I'm just surprised.

    I do a lot of work on my own bikes including wheel building, but headsets are one thing that intimidates me - especially carbon steerers. It's what bike shops are for, LOL!
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  13. #13
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    Quote Originally Posted by GKSki View Post
    I'm having trouble understanding how the compression plug is impacting the headset tightness. To me, it's in there for making the initial adjustment and to support the carbon steerer under the stem, but once the stem bolts are torqued to spec, how can the headset loosen?
    Torquing to spec doesn't always hold the stem permanently.

    Somewhere on the internet I remember reading some idiot extreme weight weenie saying once he tightens the stem in place he removes the top cap and bolt to get rid of the weight and it worked for him. It worked for the reasons you mention. But it won't always work and even best case it probably won't work long term.

  14. #14
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    Yes, but the OP is having his stem loosen after 1 ride. I can see problems with the compression plug causing the spacers and top cap to rattle perhaps, but the stem tightness holding the headset together should not be an issue (at least in a day's use). The OP is even using carbon paste between his stem and carbon steerer (generally not advised).

  15. #15
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    Quote Originally Posted by GKSki View Post
    Yes, but the OP is having his stem loosen after 1 ride. I can see problems with the compression plug causing the spacers and top cap to rattle perhaps, but the stem tightness holding the headset together should not be an issue (at least in a day's use). The OP is even using carbon paste between his stem and carbon steerer (generally not advised).
    Right.

    "I'm terrified to overtighten my steerer."

    There's a clue what's probably the cause in this case.

  16. #16
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    OP, do you use spacers both below and above the stem? On one of my bikes, when I slam the stem (without using any spacers), I get this problem. Sometimes spacers (even if thin ones like 3mm) are enough to get everything compressed up when you crank down on the compression plug.

  17. #17
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    The OP also has this same request on another site's thread with some good replies.


    Quote Originally Posted by Peter P. View Post
    Stick a ruler down the steerer and measure the distance from the end of the steerer to the top of the compression plug. Remember that number.

    Repeat your adjustments then ride the bike until your problem reappears. Remeasure and see if the compression plug is creeping up the steerer.
    The compression plug has just two functions:
    1. to set the bearing pre-load before the two pinch bolts on the stem are tightened. The stem holds the steerer after that, and the top cap is no longer necessary.
    2. to support the inside of the carbon steerer tube when it's clamped by the stem.

    The plug isn't going to creep up while riding, and that wouldn't affect the stem clamping anyway.


    Quote Originally Posted by cxwrench View Post
    4nm sounds like not enough for the compression plug. Are you sure that's the correct torque? I'm betting the plug is slipping up. You don't even have to measure anything...if it loosens up again just pull the stem off and look. Takes 20 seconds.
    The plug only needs to be tight enough to not slip while the pre-load is set. Since that top cap bolt normally needs just very light finger pressure on a hex wrench, the plug only needs moderate torque to stay in place while adjusting the pre-load.

    Checking my two bikes with a small Park Tool beam torque wrench, the top cap bolt is at:
    1. at about 5 inch-pounds, about 0.5 Nm
    2. at about 8 inch-pounds, about 0.8 Nm
    This is very light pressure with two fingers on a Y wrench.


    Quote Originally Posted by GKSki View Post
    I'm having trouble understanding how the compression plug is impacting the headset tightness. To me, it's in there for making the initial adjustment and to support the carbon steerer under the stem, but once the stem bolts are torqued to spec, how can the headset loosen?
    Yes, I agree.

    Quote Originally Posted by cxwrench View Post
    It happens all the time. It works a lot like a Shimano crank...the top cap and bolt back up the stem bolts. If the expander is loose or just sucks there is easily enough leverage in the stem/bars to wiggle it loose. What happens a lot is the expander will creep up and the headset gets loose...then someone tries to tighten the headset but there is no gap cuz the expander is higher than it should be. Huh...that's weird...throw another spacer in there w/o checking the expander. It creeps some more, same thing happens. All the time.
    No, the top cap and bolt does not "back up" the stem clamp.

    On one of my bikes, the plastic top cap itself threads onto a central threaded knob on the compression plug. There's no central cap bolt. It simply does not have enough strength in that to be a backup to the stem clamps.

    The required gap between the top of the steerer tube and the top cap is dependent on the stem and spacers, and where the stem was cut. The plug can't affect this at all.

    Quote Originally Posted by Jay Strongbow View Post
    Torquing to spec doesn't always hold the stem permanently.

    Somewhere on the internet I remember reading some idiot extreme weight weenie saying once he tightens the stem in place he removes the top cap and bolt to get rid of the weight and it worked for him. It worked for the reasons you mention. But it won't always work and even best case it probably won't work long term.
    Leave the top cap in place to keep water out. If it's bolt loosens, it'll rattle, but nothing else will happen.
    Last edited by rm -rf; 2 Weeks Ago at 09:48 AM.

  18. #18
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    A few comments on the other thread said that some bikes need more torque on the the top cap, other than just the minimal amount to remove play.

    We haven't heard back, but we are assuming the OP followed the steps correctly: 1--loosen stem pinch bolts, 2--adjust top cap, 3--tighten stem bolts. If so, trying a little more top cap torque on step 2 sounds like a good idea.

  19. #19
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    Does the top cap have enough clearance to fully seat in the spacer/stem above the top of the steerer? I've had a spacer on top that was maybe .25mm too short, which caused a similar issue. It felt fine when assembling and doing the brake rock test, but would be loose after a little bit of riding. A slightly taller spacer above the stem cured it.

    As far as 5nm is concerned, that's what I tighten all of my stem and bars to, regardless of material. It's never been an issue. The plug does not need to be very tight either... 3-4nm seems to be enough to keep it in place. It's not like it or the top cap are under any sort of load once you tighten the stem clamp. It's only there to to preload the bearings (and support fragile carbon steerers). I recently replaced a crappy Whisky compression plug with a Specialized plug. The Specialized plug fully supports the inside of the steerer under the stem clamp, unlike most others out there. This is something that you want.

  20. #20
    'brifter' is a lame word.
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    Quote Originally Posted by rm -rf View Post
    The OP also has this same request on another site's thread with some good replies.




    The compression plug has just two functions:
    1. to set the bearing pre-load before the two pinch bolts on the stem are tightened. The stem holds the steerer after that, and the top cap is no longer necessary.
    2. to support the inside of the carbon steerer tube when it's clamped by the stem.

    The plug isn't going to creep up while riding, and that wouldn't affect the stem clamping anyway.



    The plug only needs to be tight enough to not slip while the pre-load is set. Since that top cap bolt normally needs just very light finger pressure on a hex wrench, the plug only needs moderate torque to stay in place while adjusting the pre-load.

    Checking my two bikes with a small Park Tool beam torque wrench, the top cap bolt is at:
    1. at about 5 inch-pounds, about 0.5 Nm
    2. at about 8 inch-pounds, about 0.8 Nm
    This is very light pressure with two fingers on a Y wrench.



    Yes, I agree.



    No, the top cap and bolt does not "back up" the stem clamp.

    On one of my bikes, the plastic top cap itself threads onto a central threaded knob on the compression plug. There's no central cap bolt. It simply does not have enough strength in that to be a backup to the stem clamps.

    The required gap between the top of the steerer tube and the top cap is dependent on the stem and spacers, and where the stem was cut. The plug can't affect this at all.



    Leave the top cap in place to keep water out. If it's bolt loosens, it'll rattle, but nothing else will happen.
    You're under the impression that you know more than you actually do.
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  21. #21
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    Quote Originally Posted by cxwrench View Post
    You're under the impression that you know more than you actually do.
    Yeah....Bikeforums is like that. God forbid you call that guy an idiot over there.......
    "L'enfer, c'est les autres"

  22. #22
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    Quote Originally Posted by cxwrench View Post
    you're under the impression that you know more than you actually do.
    bam!!!
    Too old to ride plastic

  23. #23
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    Wow, thanks for the replies everyone.
    I took everything apart last night and reset it all according to the manual. 4nm for the plug, set at the bottom of the stem bolt, and tightened the cap until play was gone. Retorqued the stem and went to bed. Woke up to snow and 35 MPH gusts .
    I'll have to wait to test it, but I'm hoping that I wasn't tightening the cap enough as some of you suggested.

  24. #24
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    Quote Originally Posted by evan326 View Post
    ...tightened the cap until play was gone
    If this didn't solve your issue, tighten the cap until the steering gets sluggish (front wheel flop slows down). Then back off the bolt just enough until the steering is free and easy again. The principle at work here is "you don't know the right setting until you've gone past it."

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