Results 1 to 5 of 5
  1. #1
    FM
    FM is offline
    luxatio erecta
    Reputation: FM's Avatar
    Join Date
    Apr 2003
    Posts
    8,995

    Min. steerer tube / stem contact

    Building up a new 29er frame, and unfortunately the steerer tube on my fork is a little shorter than ideal.

    The stem has a stack height of 38mm, and I've got 31mm of steerer up into the stem with 7mm void. The top of the steerer is just above the upper stem pinch bolt (no spacers obviously).

    I'm thinking I should replace the CSU, but there's probably enough contact for 2-3 rides (nu hucking!) until the new CSU arrives. I also have a 35mm stack height stem (same length) I could use.

    Not sure what a fox 34 CSU runs....

    Thoughts?

  2. #2
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    2,422
    Rule of thumb is usually that the steerer has to be at least up to the top stem bolt. Sounds like you are good.

  3. #3
    mtbr member
    Reputation: syl3's Avatar
    Join Date
    Apr 2008
    Posts
    904
    Yeah you're good.

    I had 24mm of steerer available and no stem would grab with both bolts so i ran a Thomson Elite 1-bolt stem for 8000km with no issues. You'll be just fine with 31mm.

  4. #4
    FM
    FM is offline
    luxatio erecta
    Reputation: FM's Avatar
    Join Date
    Apr 2003
    Posts
    8,995
    Awesome- thanks for the second opinions!
    I figure I've got 80% insertion...

  5. #5
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,343
    The center of the upper pinch bolt is a good rule of thumb. I'd go that low in a heartbeat even if it means a 7 mm void.

    Also looking into the stem reveals where the steerer tube makes contact with the stem. Quite often there are cavities and cut-outs for lightness and the contact area is smaller, so watch out for that.

    As usual, there is an exception: carbon steerer tubes should poke all the way through the stem and have a spacer on top of them, because the end of the tube is more susceptible to damage.

Similar Threads

  1. Stem/Steerer Tube Shims?
    By rmalling in forum Colorado - Front Range
    Replies: 9
    Last Post: 06-25-2014, 03:52 AM
  2. Steerer Tube Diameter / Stem Steerer Diameter?
    By cirruslk in forum Urban/DJ/Park
    Replies: 1
    Last Post: 08-27-2013, 04:47 PM
  3. Manitou SX, top of stem 3/8" above steerer tube?
    By chimpanzee00 in forum Shocks and Suspension
    Replies: 1
    Last Post: 05-28-2012, 07:24 PM
  4. Safe to use steerer tube slightly shorter than stem clamp?
    By Dirt Bringer in forum Shocks and Suspension
    Replies: 8
    Last Post: 03-17-2012, 07:39 PM
  5. Looooong steerer tube/stem question
    By henrypig in forum Frame Building
    Replies: 11
    Last Post: 03-26-2011, 06:04 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •