Stem too tall for steerer?

Andyh4324
Andyh4324 Posts: 58
edited May 2014 in Workshop
Just installed a new stem to my bike but it seems to be a bit taller than the old one. The stem is about 4mm proud of the steerer etc inside (see pic) Is this ok or should I be looking to get a shorter spacer to lower it down a bit? The top cap screws on ok.

Sorry if it's maybe a silly question but I'm just starting to do bits myself on the bike and not come across this before.

14219707043_85e21a59e1.jpgIMG_0193

Comments

  • on-yer-bike
    on-yer-bike Posts: 2,974
    This will be fine you need a gap for when you load the bearings by tightening the cap bolt, 3mm would be better. However, ideally you should have a spacer on top of the stem so that top bolt of the stem isnt clamping on the edge of the steerer as it will be in your arrangement. Be very careful not to over tighten the stem bolts definitely NOT 6Nm as it says on the stem otherwise you will crack the top of the steerer.
    Pegoretti
    Colnago
    Cervelo
    Campagnolo
  • g00se
    g00se Posts: 2,221
    Is the steerer carbon? It's getting close - that sort of bung sits a little proud of the steerer - so you need to consider where the steerer top alligns with the top bolt. if it's below, then a lot of the clamping force will be from the bolt below - which may result in a point loading on the steerer that is a risk. Similarly, if the top clamp bolt is right on the edge of the steerer, then there is more of a risk of it splitting.

    I've had a very reputable LBS refuse to work with a similar setup with a bike I bought. There were no spacers below so it was find a lower stack height stem or a new fork.
  • Andyh4324
    Andyh4324 Posts: 58
    So to be safe I need to get a smaller spacer below? There's 2 x 10mm spacers so do I change 1 to a 5mm or something? What size do you guys recommend? Yes the steerer is carbon I believe.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    Three options from what I can make out with my failing eyes from that picture:

    1. If the top stem bolt clamps onto the stem, stick with what you have - I can't see a problem.

    2. If you want, get rid of one of the 10mm spacers and fit a 5 then fit stem and off you go.

    3. Get rid of all spacers, slam that stem as its designed to be and off you go.
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • Andyh4324
    Andyh4324 Posts: 58
    Ok so I've done some research and my new stem is 1.5mm taller than the old one. For the time being I have a 10mm above and below the stem as the top clamp bolt was right on the end of the steerer and bung. Ordered spacers that total 18mm to make up the difference and I should be good to go shouldn't I?
  • g00se
    g00se Posts: 2,221
    Personally, I would put a small spacer at the bottom (2.5mm or 5mm) - and another 5mm at the top. By putting one at the top, you allow yourself a bit of room to accommodate the top-cap if the steerer protrudes a little. Some fork manufacturers recommend a spacer below in all circumstances (Trek?) to avoid point loading.

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