Stem Installation

b4beezer
b4beezer Posts: 12
edited September 2010 in Workshop
Hi all,

Hope you are well. Just replaced my Specialized stem with a FSA stem. The FSA installation manual recommends leaving a 3-5mm gap between the top cap and the top of the stem (if i'm reading it right). Does this sound correct?

The specialized stem I replaced had a wedged insert so that it fitted perfectly (no visible steertube). This wedge however will not fit into the FSA stem.

Cheers

Comments

  • ChrisSA
    ChrisSA Posts: 455
    The wedge would go inside the steerer tube. The top of the stem (and therefore top cap) should be higher than the top of the steerer. A slight preload is needed to ensure the stem is pushed down lightly to take the slack out of the headset.

    Try loosening the wedge. Does it go in the steerer tube without any stem installed?
  • Ben6899
    Ben6899 Posts: 9,686
    Wait a minute. This wedge... is it more of a shim? That fits around the steerer and then the stem fits over the wedge? I.e. the Specializied stem you had was adjustable?

    If that's the case, lose the wedge: the FSA stem doesn't need it.

    The recommended gap is between the top of the steerer/star nut or expander plug and the top of the stem. If the gap isn't there, then the top cap will bottom out before being 'tightened' enough to remove the bearing play.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
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  • The wedge fits fine over the steerer tube without the stem, but there is gap of around 3mm when the top cap is fitted. Guess I probably need to look at a headset spacer to cover the gap.
  • Ben6899
    Ben6899 Posts: 9,686
    Have you got pics? I'm struggling to imagine what this 'wedge' is.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
    Instagram: https://www.instagram.com/ben_h_ppcc/
    Flickr: https://www.flickr.com/photos/143173475@N05/
  • Apologies for the terminology. Would headset outer sleeve be correct? This sleeve fits over the headset then the stem fits over it.

    Here is a picture of the newly installed stem (still using the spacers that came with the bike),

    4998942171_0836e08050.jpg

    Is another spacer needed? Should the space stay?

    Cheers
  • Ben6899
    Ben6899 Posts: 9,686
    Ah right, it is a shim. I'm guessing the Specialized stem was deeper than the new FSA one?

    Regardless of shim/wedge as far as I can tell, you need 3mm from the top of the stem/spacer(s) combination to the top of the steerer itself. If you don't have enough clearance then when you 'tighten' the top cap, it will hit the steerer plug before pulling the play out the bearings.

    ~3/4 down the page for a diagram of what I'm getting at: http://www.parktool.com/repair/readhowto.asp?id=65

    Hope this helps!
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
    Instagram: https://www.instagram.com/ben_h_ppcc/
    Flickr: https://www.flickr.com/photos/143173475@N05/
  • Thanks for this Ben. The smallest spacer I can find is 5mm. I trust it is fine for the stem to be a couple of mm higher than the steerer (as seen in a picture in this Parks tool article)?
  • Ben6899
    Ben6899 Posts: 9,686
    You're welcome.

    3mm is the recommended height difference (stem higher), you could probably get away with 5mm.

    Looking at your photo, a 5mm spacer on that arrangement might not be enough.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
    Instagram: https://www.instagram.com/ben_h_ppcc/
    Flickr: https://www.flickr.com/photos/143173475@N05/