Question about steerer length

Niland
Niland Posts: 35
edited August 2007 in Workshop
Trying to work out what length of fork steerer is right for my bike. So from the base of the head tube is it to the top of the headset stack (i.e. before the stem) or to the top where the stem allen key is?

Simple question I hope! I've just never changed a fork so never come accros it.

Comments

  • MarvintheAndroid
    MarvintheAndroid Posts: 409
    Normally about 3 mm below the top face of the stem (cap nut). Think about it - you need the steerer tube to be clamped by the stem, so no point cutting it below that.

    Regards

    Marv
    What tree ? ...........

    Trek 8000 ZR XC hardtail.
  • Monty Dog
    Monty Dog Posts: 20,614
    Ahead forks generally come with a standard steerer length of 300mm. NEVER cut a fork until you've tried it in situ complete with headset, spacers and stem. As said, cut the fork about 3mm less than the top of the stem clamp when you've got the stem, bar height right.
    Make mine an Italian, with Campagnolo on the side..
  • Niland
    Niland Posts: 35
    Thanks, that is what I thought it would be! I just read this on wiki:"The length of the steerer tube should be greater than but approximately equal to the head tube length plus the stack height of the headset." and got a bit confused.
  • Bronzie
    Bronzie Posts: 4,927
    The correct length is:
    = the length of the head tube on your bike
    + the stack height of the headset bearings (as quoted by manufacturer)
    + any spacers you want under the stem
    + the clamp height of your stem
    - the 3mm as stated above.

    But as already pointed out, the best way to get it right and avoid a costly fcuk-up is to assemble the whole lot uncut so there is no play, mark where the top of the stem comes on the steerer, then mark a line 3mm below this on the steerer and cut it there.

    And remember - Measure twice, cut once!!
    It's a Lifestyle! -+-+- Coggan Training Levels
  • bobtravers
    bobtravers Posts: 115
    All answers are very good, might cut 1 inch over your stem, try the bike to see if the riding position is good, and then cut 3 mm over the stem, finally put the stem cap...
  • luceberg
    luceberg Posts: 158
    Niland,

    Wiki is a bit out of date as most steerer tube to handlebar interfaces are now Aheadset, which is different from the old fashioned Quill stemmed variety.

    Quill stems fit inside the steerer tube, which, as Wiki states, finishes just below the headset nut and is threaded to accept said nut.

    Then assuming your fork is of the more normal nowdays threadless variety, the above posts are relevant.If it is threaded, then Wiki is.
  • MarvintheAndroid
    MarvintheAndroid Posts: 409
    Did you correct the entry, Luceberg ?

    Marv
    What tree ? ...........

    Trek 8000 ZR XC hardtail.

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