Headset adjustment

bikeit65
bikeit65 Posts: 995
edited September 2012 in Workshop
I am going to be replacing the stem on my Cannondale bike soon,
i have removed headsets before but not one like the SI unit on the Cannondale bike. Other headsets had a bolt and a top cap. I looked at the Si unit and the allen key goes inside the unit.
So do i adjust the Cannondale SI compression unit the same as other head set units?
https://www.instagram.com/seanmcgrathphotography/
Trek Domane SL7 GEN4
Planet X RT58
Cannondale CAAD 10 2012.
Pain.. Is weakness leaving the body.

HATING LIFE-CYCLES FROM 2011

Comments

  • sungod
    sungod Posts: 16,863
    sounds like it's an expansion bung (for carbon fibre steerer tube), rather than a starnut (for alloy steerer tube)

    if you are simply changing the headset, you don't need to touch the bung

    just remove the top bolt and cap, undo the stem

    drop out the forks

    replace headset

    insert forks, slide stem on but do not tighten it

    replace cap and bolt, tighten bolt until it's *just* taken out the slack in the bearings, finger tight is often enough

    a) tighten stem

    straddle bike, grab bars, hold front brake on hard, shove back/forth to check there's no play in the bearings

    if there's play, loosen stem, tighten top bolt a smidge, go back to point a)

    if there's no play, that's it
    my bike - faster than god's and twice as shiny
  • Sungod its the FSA SI compression unit, the top cap has a 6mm allen key slot in it but there is also an expander bolt inside this, its on alloy bars.
    I am only changing the stem to a longer one.
    https://www.instagram.com/seanmcgrathphotography/
    Trek Domane SL7 GEN4
    Planet X RT58
    Cannondale CAAD 10 2012.
    Pain.. Is weakness leaving the body.

    HATING LIFE-CYCLES FROM 2011
  • https://www.instagram.com/seanmcgrathphotography/
    Trek Domane SL7 GEN4
    Planet X RT58
    Cannondale CAAD 10 2012.
    Pain.. Is weakness leaving the body.

    HATING LIFE-CYCLES FROM 2011
  • desweller
    desweller Posts: 5,175
    You don't need to touch the bung or the headset

    1. unscrew the pinch bolts on your old stem
    2. undo the top cap
    3. remove the old stem
    4. fit new stem and bars etc
    5. refit the top cap and tighten until headset play is eliminated
    6. check that bars are straight and tighten the pinch bolts
    - - - - - - - - - -
    On Strava.{/url}
  • nweststeyn
    nweststeyn Posts: 1,574
    As above, but to clarify what the other parts are for incase people are reading this trying to find an answer:

    The 5mm allen bolt is responsible for 'expanding' the bung and holding it in place. This then becomes the anchor point for the top cap (6mm bolt) which creates the 'loading' on the bearings.
  • Thanks folks for all your help greatly appreciated. Will let you know how i get on
    https://www.instagram.com/seanmcgrathphotography/
    Trek Domane SL7 GEN4
    Planet X RT58
    Cannondale CAAD 10 2012.
    Pain.. Is weakness leaving the body.

    HATING LIFE-CYCLES FROM 2011
  • Okay i didnt get a new stem on the advise of some guys from the club so i flipped the stem that was on the bike to give the bars a little more height. hopefully this stops the pain in my hands.
    The job was quite simple in the end and a lot easier to work on than previous headsets i have worked on.
    https://www.instagram.com/seanmcgrathphotography/
    Trek Domane SL7 GEN4
    Planet X RT58
    Cannondale CAAD 10 2012.
    Pain.. Is weakness leaving the body.

    HATING LIFE-CYCLES FROM 2011