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  1. #1
    Junior Member kaltsoplyn's Avatar
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    Are spacers above the stem necessary?

    Hello all,

    I use a fork with a 1 1/8" steerer, a standard headset, some spacers, my stem and, on top of it all, my headset cup and star nut bolt. No surprises.

    I want to remove some spacers from the steerer column and put a bracket (the function of which is irrelevant for this discussion), which, however, can not be used as a structural part of the assembly (i.e. it can not withstand the vertical forces exerted on, say, a spacer).

    What I'm thinking is this:
    1. put the stem right on top of the headset
    2. use all spacers and star nut bolt to tighten things up
    3. tighten the stem bolts

    and the question is this:
    Can I then remove the spacers and headset cup from above the stem?
    Do they serve any purpose? I mean with the stem holding the fork tightly and under pressure and all.

    I do have the feeling that someone will respond "Sheldon Brown did it with a seat clamp."

  2. #2
    Constant tinkerer FastJake's Avatar
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    Spacers above the headset are not necessary once the headset is adjusted and the stem is tightened. They are only there for appearance.

    Says Sheldon: "Once the stem binder bolts have been tightened, the adjusting bolt that goes to the star nut is under no significant stress, and may even be removed."

  3. #3
    cab horn
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    Quote Originally Posted by FastJake View Post
    Spacers above the headset are not necessary once the headset is adjusted and the stem is tightened. They are only there for appearance.

    Says Sheldon: "Once the stem binder bolts have been tightened, the adjusting bolt that goes to the star nut is under no significant stress, and may even be removed."
    Learn how to read.

    He says nothing about spacers above the stem. He only says that the top cap bolt is redundant after the headset preload has been set. By your own quote

    If the steerer is carbon fiber, you will want a 5mm spacer above the stem. Alloy steerers you can get away with the 'highest' stem bolt being below the top of the steerer.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  4. #4
    Surf Bum
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    As long as this is a steel steerer we are talking about, that is correct. If it is a carbon fork with carbon steerer, the manufacturers usually (always?) specify that one spacer must be used on top of the stem.

    Edit: Looks like Operator's post loaded while I was typing. Same point. Carbon requires a top spacer.

  5. #5
    Junior Member kaltsoplyn's Avatar
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    Thank you all.

    I should have mentioned that it is, actually, a steel steerer. So I guess it'll be ok.

    @operator: If the cap bolt goes away, then don't spacers on top of the stem serve the sole purpose of producing a nice rattling noise? Just kidding, but did you mean that you need a 5mm space (instead of a spacer) above the stem for carbon steerers? Which is, of course, reasonable for carbon.

  6. #6
    cab horn
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    Quote Originally Posted by kaltsoplyn View Post
    Thank you all.

    I should have mentioned that it is, actually, a steel steerer. So I guess it'll be ok.

    @operator: If the cap bolt goes away, then don't spacers on top of the stem serve the sole purpose of producing a nice rattling noise? Just kidding, but did you mean that you need a 5mm space (instead of a spacer) above the stem for carbon steerers? Which is, of course, reasonable for carbon.
    It doesn't matter. No one removes their top cap bolt after setting the headset preload anyways. It's dumb. Sheldon only mentions that as a curiosity.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

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    Junior Member kaltsoplyn's Avatar
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    Quote Originally Posted by operator View Post
    It doesn't matter. No one removes their top cap bolt after setting the headset preload anyways. It's dumb. Sheldon only mentions that as a curiosity.
    Did you just call me dumb? Don't go around forums calling people dumb. Someone might track down your bike and steal your top cap bolt. Make you look dumb.
    Besides, silly, the cap bolt and spacers will still be there, putting a load on the extra bracket I'm putting on the steerer. I just didn't want to put it under the full load.

    Anyhow, I think I did get my answer: it is doable, it is probably safe, I wouldn't trust it as much as the complete setup and go racing downhill.

    Cheers

  8. #8
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    Quote Originally Posted by operator View Post
    No one removes their top cap bolt after setting the headset preload anyways.
    Erm ....Yes they do.

    Some people put light electronics into the steerer ... some have a cable running through there, It's a few extra gram's if your really really obsessed about weight

    For a while my brother and I actually shared the same compression bolt because we were too cheap to buy two.

    There are lot's or reasons to take it out .. but I can only think of two to leave it in ... and one of those is rather dubious

    1. to fill the hole and make it look better
    2. If the stem work's loose on the trail you can re-tighten easily.

    Some people would argue that since it is no longer needed that NOT removing it is dumb .... afterall it's just added weigh which isn't actually doing anything.

  9. #9
    Constant tinkerer FastJake's Avatar
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    Quote Originally Posted by kaltsoplyn View Post
    but did you mean that you need a 5mm space (instead of a spacer) above the stem for carbon steerers?
    I don't think operator meant this, but that would be correct. The SPACERS above the stem (and the top cap) are not structurally holding anything together. The reason you need a 5mm SPACE above the stem on carbon steerer tubes is so the tube doesn't get crushed when someone tries to space it up too high.

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    If your stem ever gets knocked out of position it will be an ordeal to straighten it. You might want to put a locking spacer under the stem or discuss what type of bracket you are installing, maybe we can suggest an alternative that can withstand the preload pressure.

  11. #11
    Senior Member mechBgon's Avatar
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    I admit I'm curious what sort of bracket can't withstand the mild force required to preload a headset.

  12. #12
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    If your stem is properly tightened, and holds well the top cap and screw is no longer necessary and can be removed. But something that no one has brought up is that some headset and stem combinations absolutely require a spacer between the stem and headset centering cone.

    When you set it up, look under the stem and make sure you see daylight between the stem and headset all the way around, with the stem touching only on the centering (split) cone.

    Lastly, if the headset doesn't hold adjustment, and you need to improve stem clamping, consider using some coarse lapping compound between the stem and steerer. That'll provide some mechanical bite between the two parts and give great hold without having to overtighten the stem.
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  13. #13
    cab horn
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    Quote Originally Posted by Fish_man View Post
    Erm ....Yes they do.

    Some people put light electronics into the steerer ... some have a cable running through there, It's a few extra gram's if your really really obsessed about weight

    For a while my brother and I actually shared the same compression bolt because we were too cheap to buy two.

    There are lot's or reasons to take it out .. but I can only think of two to leave it in ... and one of those is rather dubious

    1. to fill the hole and make it look better
    2. If the stem work's loose on the trail you can re-tighten easily.

    Some people would argue that since it is no longer needed that NOT removing it is dumb .... afterall it's just added weigh which isn't actually doing anything.
    Thanks, you qualify as dumb.

    Go look on 99.999% of the bikes out there with threadless headsets. Are the top caps gone? Didn't think so.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  14. #14
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    Quote Originally Posted by operator View Post
    Thanks, you qualify as dumb.

    Go look on 99.999% of the bikes out there with threadless headsets. Are the top caps gone? Didn't think so.
    Jesus man. Whats your problem ?

    Why is removing the top cap dumb? After the stem is tightened it serves no purpose what so ever so why is removing it so dumb?

    and what makes me dumb ? Because I state FACT's instead of just stating my opinion?

  15. #15
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    Quote Originally Posted by operator View Post
    Thanks, you qualify as dumb.

    Go look on 99.999% of the bikes out there with threadless headsets. Are the top caps gone? Didn't think so.
    That was uncalled for, even for you.

    I agree that it makes sense to leave the top cap and nut in place, if only for convenience or to avoiding losing them, but they are not absolutely necessary if the stem has enough hold to retain the adjustment.

    I do race service for events, and often need to share the top cap assembly between two bikes when someone is missing parts or a similar reason. Having done this a number of times I assure you that it kept lots of folks in the race, and none have ever DNFed because of a headset problem.
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  16. #16
    Constant tinkerer FastJake's Avatar
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    Quote Originally Posted by operator View Post
    Thanks, you qualify as dumb. Go look on 99.999% of the bikes out there with threadless headsets. Are the top caps gone? Didn't think so.
    Dude... You're a jerk.

    Sheldon must be in the .001%


  17. #17
    cab horn
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    Quote Originally Posted by FastJake View Post
    Dude... You're a jerk.

    Sheldon must be in the .001%

    My bad, I see that on production bikes all the time.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  18. #18
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    I think I have 6 threadless-headset bikes in my possession, I have two topcaps and one compatible screw.

    I think the point to be made it that, functionally, if a threadless headset is assembled correctly, it does not matter what is above the stem. You can have a holster for your 9mm; you could have 9 inches of uncut steerer tube with a bright pink rubber phallus top cap; many would have both.
    Spacers, devices, brackets, elastics, hood ornaments - it doesn't matter what is above the stem.

  19. #19
    Used to be Conspiratemus
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    ^ Best post of this thread, bar none! (Although FBinNY's were more informative....)
    "I did not know that!" -- J. Carson

  20. #20
    bike whisperer Kimmo's Avatar
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    Quote Originally Posted by mechBgon View Post
    I admit I'm curious what sort of bracket can't withstand the mild force required to preload a headset.
    Ssshh... structural, or engineering, cheese is still sooper sekrit

  21. #21
    coprolite fietsbob's Avatar
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    You cannot easily make a short fork longer, but, by putting some spacers above the stem
    you can make a long steerer shorter, and change your mind later and make it longer again.

  22. #22
    Junior Member kaltsoplyn's Avatar
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    I was reluctant to share the exact nature of the "bracket" as I am sure it's going to draw some child-abuse-paranoia fire on me.
    But anyway, here goes; this may be fun.

    The bracket is the mounting block for the bobike mini+, steerer/stem mounted child seat:
    here is the mounting bracket
    here is the manufacturer intended assembly

    This bracket is designed for threaded stems, where it sits on top of the headset locknut.
    The part holding onto the steerer is some sort of mildly hard plastic. THIS is the part which will be compressed by the spacers and I felt unsure about whether I really wanted to do that.

    Now, by the end of the year the company is putting forward a threadless ATB version of the block, where I assume the clamp part will be designed with the headset preload in mind, but until then I wanted to take my daughter out for a few spins around the park. So, this is the solution I came up with and I thought I'd ask you guys.

    Having read all the nice posts above I think it's doable. BUT, coming to think about it, I now feel that a bigger problem with this setup is that the higher position of the seat will provide a much larger leverage for my daughter's weight to apply some significant torque/stress on the headset bearings. Bah, I think it'll be ok for a few easy rides...
    Last edited by kaltsoplyn; 11-15-10 at 02:20 AM. Reason: hyperlink correction

  23. #23
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    I don't think putting the seat higher than the stem would work from an ergonimic standpoint. Get a locking spacer and put it direcly over the headset and set the preload. Afterwards you can put the bracket under the stem without having it under compression.

  24. #24
    Junior Member kaltsoplyn's Avatar
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    Quote Originally Posted by Bezalel View Post
    I don't think putting the seat higher than the stem would work from an ergonimic standpoint. Get a locking spacer and put it direcly over the headset and set the preload. Afterwards you can put the bracket under the stem without having it under compression.
    Thanks for the sanity. I 'm still on hold for some answer along the "CHILD KILLER!!! CHILD KILLER!!!" style.

    Anyway I went on a small test ride with a ~10kg flour bag (whole wheat!), bracket mounted above the stem. No major handling issues detected.
    Besides the bracket holes are too close to the steerer and, when placed below the stem, the seat itself does not clear the stem to be inserted properly. So, putting the existing bracket below the stem is a no-go.

  25. #25
    Subjectively Insane MilitantPotato's Avatar
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    Oh, to add even more fun, if you have a cable hanger or seatpost clamp of the correct size you can clamp that down once you've set your preload, and you need no spacers (or stem if you're a hands free pro) at all!
    You've got a bike, so you gotta move.

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