Results 1 to 4 of 4
  1. #1
    mtbr member
    Reputation:
    Join Date
    Nov 2008
    Posts
    2

    converting 26" mtb for a small cross bike

    I coach a few kids who are between 24" wheel 'cross bikes and 700c bikes. Thinking of converting a 26" mtb to 'cross for them. I figure early 90's mtbs made for rigid forks are the easiest choice.

    But could something lighter, like this work? Vintage Specialized s Works Mountain Bike Frame x Small Green and s Works Cranks | eBay

    Can't tell for sure, but seller says it had a 2" fork. Thinking a regular short rigid fork to keep the top tube low. But then would the bb be too low? Handling funny? Maybe with shorter cranks, eg 155mm?

    Not sure the year either. Googling suggests it may not be a '94-96 bike, which means it may have been later, and had a longer fork.

    Thanks

  2. #2
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    825
    Difficulty with using a MTB frame as a cross bike is that the headtube height (and stem/bar position) is usually really low and/or the top tube length is very long in comparison to a frame designed for drop bars, particularly if you were to use a frame designed for a suspension fork and put on a shorter rigid fork, dropping the front end even further. The head-tube angle will also change by about 1 degree for each 20mm difference in fork height. MTB frames usually have fairly high bottom bracket to start with, a bit of BB lowering is probably fine, particularly in conjunction with shorter cranks.

    For CX width 26" (559mm) tires, only option seems to be CX Pro HS 269 | Schwalbe North America
    most all real offroad MTB tires are significantly wider. There are also 26" road slicks in CX width but having some tread is a good idea for most conditions.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Nov 2008
    Posts
    2
    Quote Originally Posted by GrayJay View Post
    Difficulty with using a MTB frame as a cross bike is that the headtube height (and stem/bar position) is usually really low and/or the top tube length is very long in comparison to a frame designed for drop bars, particularly if you were to use a frame designed for a suspension fork and put on a shorter rigid fork, dropping the front end even further. The head-tube angle will also change by about 1 degree for each 20mm difference in fork height. MTB frames usually have fairly high bottom bracket to start with, a bit of BB lowering is probably fine, particularly in conjunction with shorter cranks.

    For CX width 26" (559mm) tires, only option seems to be CX Pro HS 269 | Schwalbe North America
    most all real offroad MTB tires are significantly wider. There are also 26" road slicks in CX width but having some tread is a good idea for most conditions.
    Thanks.
    Given that I'm looking at a 13 or 14 frame for a kid, I'm guessing their seat will be low and the low head tube shouldn't be an issue.

    Similarly, for the longer top tube on flat bar frames, I'm guessing that would not be a bad thing on a cross bike, as long as I can get the stem short enough.

    Would there be much difference in top tube length for small size bike between brands, and eras of mtbs?

  4. #4
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    444
    Islabikes makes a nice 26 inch cross bike for $600 new.
    My son loves his.
    Otherwise go flat bar with schwable 26 1.35 cross tires
    Rocky Mountain Element
    Orbea Lobular CX

Similar Threads

  1. Real Road/Cross bike or "custom" Mountain Bike?
    By ALS650L in forum Commuting
    Replies: 17
    Last Post: 09-26-2013, 08:35 PM
  2. Anybody regrets converting a 26" bike to a 650b?
    By jazzanova in forum 27.5 - 650b
    Replies: 27
    Last Post: 11-05-2012, 03:11 PM
  3. Inbred as a "cross" bike?
    By Slash5 in forum On One
    Replies: 4
    Last Post: 05-20-2012, 06:18 AM
  4. OT: Looking for a 24" wheel cross bike for my son
    By yogidave in forum Colorado - Front Range
    Replies: 4
    Last Post: 09-08-2011, 09:22 AM
  5. Is my bike too small? 5'11", riding 17" frame
    By derailin_palin in forum Bike and Frame discussion
    Replies: 36
    Last Post: 03-14-2011, 09:33 AM

Posting Permissions

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