Under stem spacer(s)

Hi, I got back into cycling a few months ago (hybrid and then road bike).
The road bike is a Cube Attain with a full carbon fork. Originally it had about 20mm of spacers above the cone spacer (headset cover) and the stem fitted at the top.

A while ago, I cut the from tube and had a 10mm below and 5mm above the stem. I'd like the bars to go a bit lower. I was thinking of removing the 10mm spacer under the stem (so it sits on the 25mm cone spacer), trim the tube and still have the 5mm above.

After a bit of research, it seems there are people who say its fine and others that say that the stem being in contact with the cone is bad and you need a 5mm normal spacer under the stem.

Seems a bit strange to me as the mating surface on the cone spacer is the same as a normal spacer but any advice from more knowledgeable bike tinkerers would be appreciated before I do any cutting.


  • Forgot to add, for more detail. The expansion plug is one that's around 40mm long and has a collar that sits on top of the steerer tube. With around 2mm of tube appearing above the stem, the plug supports the full stack height of the stem.
  • super_davo
    super_davo Posts: 1,164
    Lots of people slam their stem, there are even entire sites devoted to it...


    95% of bike and headsets will be fine with no spacer. However to be sure, flip the spacers over to the top, ride it like that for a couple of weeks, trim it when you are sure it is right for you. You don't need to trim it immediately and you may find a comfort issue over a mechanical one.
  • MattFalle
    MattFalle Posts: 11,644

    If the OP is asking

    a) can he have stem on top of cone spacer then yes

    b) no spacers on top of stem then so long as gap betwixt top of stem and steerer is sufficient to allow compression of headset bearings then yes

    c) dump the cone spacer, fit flat cover instead and slam it like its meant to then yes

    people who say stem can't sit on top of cone spacer are talking totalbollox and will most probably be in a club, so ignore them.
    The camera down the willy isn't anything like as bad as it sounds.
  • Matt, option A was the question I was asking :)

    Thank you both for the replies. Much appreciated.
  • MattFalle
    MattFalle Posts: 11,644
    No worries dude - pleaseure to help any time.
    The camera down the willy isn't anything like as bad as it sounds.