Results 1 to 4 of 4
  1. #1
    mtbr member
    Reputation:
    Join Date
    Mar 2015
    Posts
    129

    Weird build idea

    Cross posted from the womens' forum.

    I recently repossessed my old mountain bike from my daughter, and now she's griping because she doesn't have a bike. 21 yo college student, lives in Florida.

    What she didn't like about the mtb, aside from the fact it's too big for her, is that it handled crappily on pavement. But, she's not giving up on the idea of riding trails, she's just not totally sure what she is going to want to do once she gets into it.

    The idea of a cx has a lot of appeal, and I've thought about building her up a straggler 650b, although she doesn't really want me to drop that kind of money just yet. Plus, once you start getting into the smaller frame sizes, the geometry goes all slack. Which is fair enough, you gotta stuff some wheels in there somehow. But if she wants sharp handling, I dunno that she's going to be delighted with that frame.

    So here's one idea.

    Nashbar has a chromoly cx frame that has:
    Head tube 70.5 degrees
    Seat tube 73 degrees
    Eff top tube 54cm

    Now, that reach is gonna be too long for drops I think, but it puts her smack on the money for reach to a flat bar.

    My thinking is, mount up 650b wheels, I'll bet I'll be able to squeeze some 42ish tires in there, maybe more eh. Slap in some BB7's, gtg.

    I think I like this geometry, but I wish the reach was a little less so I could put some drops on there. Dang this is frustrating, I mean the whole thing is trying to squeeze some fat tires into a compact, agile frame. I was kind of hoping the 650b wheelsize would allow that geometry to work its way down into the smaller frame sizes.

    Is this as good as it gets?
    Last edited by TampaDave; 04-05-2015 at 03:30 PM.

  2. #2
    mtbr member
    Reputation: Eric Malcolm's Avatar
    Join Date
    Dec 2011
    Posts
    626
    Ah.. Father's problems.

    It would be possible to do, but as a frame/bike builder, my approach is different. I am almost finished building a bike for my daughter using 700x35 tyres, 520mm EfT, 70.5* head, 51mm offset, with a very steep ST of 76*, Flat bar, plenty of toe clearance from the front wheel. I made the set-up, so that I could make it work with a 90mm h/bar stem. I could use a drop-bar and short stem, so, yes, it could be done.

    Eric
    If I don't make an attempt, how will I know if it will work?

  3. #3
    mtbr member
    Reputation:
    Join Date
    Mar 2015
    Posts
    129
    Very cool.

    I wound up building out a 14" Nashbar aluminum mtb frame with drop bars. That frame has really interesting geometry, I lay awake at night trying to wrap my head around it. They use the same length chainstays on every size, so in the smaller size the chainstay/wheelbase is pretty high. Really short reach in every size.

    They say it has a 71degree hta but the don't specify a fork length, they say to use an 80 or 100mm sus corrected fork. So... which one is it?

    Wound up putting a 440/43 Soma fork on it, and a 40 degree stem, 120mm iirc. Junebug bars. Gives her 68mm of trail if I have my numbers right.

    Wound up coming together kinda nice. She has a nice comfy riding position, the drops are just below seat level so it should be good on the dirt I think. The bike is very quick on the street with great in-line stability. Tends to dive into turns a bit. For 99 bucks it holds her components and is giving her a little taste of the cx world.

    Love your approach though. I think for us short folks the slack hta/big offset idea has a lot going for it. Mighta shoulda gone with the nashbar fork, a little longer, a little more rake, trail numbers about the same.

  4. #4
    mtbr member
    Reputation: Eric Malcolm's Avatar
    Join Date
    Dec 2011
    Posts
    626
    You got a picture to Post?

    Here's mine.

    Name:  IMG_0602.JPG
Views: 26
Size:  32.9 KB

    Eric
    If I don't make an attempt, how will I know if it will work?

Similar Threads

  1. Trans-AM29er build idea
    By SlowerThenSnot in forum Transition Bikes
    Replies: 4
    Last Post: 06-08-2013, 09:04 PM
  2. Trail idea, first build. help me get it right.
    By RobinGB in forum Trail Building and Advocacy
    Replies: 7
    Last Post: 12-01-2012, 09:49 PM
  3. Fun build idea?
    By Crashman1 in forum General Discussion
    Replies: 0
    Last Post: 07-21-2012, 12:44 AM
  4. New idea for ultimate Easy2LED housing build
    By bikerjay in forum Lights DIY - Do It Yourself
    Replies: 9
    Last Post: 02-22-2012, 10:37 AM
  5. Replies: 1
    Last Post: 09-24-2011, 12:30 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
  •