Replacing Rear Triangle

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  • 12-04-2012
    jb9
    Replacing Rear Triangle
    I am newbie. I have an old lugged stumpjumper that needs a new chainstay and new dropouts. Would it be worth it to perhaps just try and replace the entire rear triangle? If I could cleanly remove the chainstays and clean the lug of brass (without heat), would it be worth trying this? I have learned a lot from all the experienced framebuilders who contribute here, so I figured I would ask for some opinions. The frame does have some sentimental value and it is kind of a tank so it makes me sad to trash it.

    thanks in advance.
  • 12-04-2012
    Walt
    Go for it
    Most likely you will end up trashing the frame anyway, but you will learn a LOT working on the project.

    So: if the frame has serious sentimental value, build something else (a new frame!) and do some practicing before tackling the Stumpy. If it has limited sentimental value then just start hacking it apart and try to fix it. Worst case scenario; it's in the trash like it would have been anyway. Best case; you successfully restore the old girl. Either way you'll learn a ton.

    -W


    Quote:

    Originally Posted by jb9 View Post
    I am newbie. I have an old lugged stumpjumper that needs a new chainstay and new dropouts. Would it be worth it to perhaps just try and replace the entire rear triangle? If I could cleanly remove the chainstays and clean the lug of brass (without heat), would it be worth trying this? I have learned a lot from all the experienced framebuilders who contribute here, so I figured I would ask for some opinions. The frame does have some sentimental value and it is kind of a tank so it makes me sad to trash it.

    thanks in advance.

  • 12-04-2012
    TrailMaker
    What Walt said; :thumbsup:

    If you can braze, give'r a go. Oddly, if you can do copper plumbing, you've already got some feel for sweat brazing lugs. If you can't and you really like that beast, start hacking around with some other scrap stuff first. You can easily and fairly well replicate sweat brazing by simply sleeving some scraps of tube together. It should be an elemental enough frame in terms of construction to offer you a reasonable chance at success. Sounds like a perfect way to get started to me. If it were not for a TON of varied/applicable prior fabrication experience, I'd have done the same thing!

    There is plenty of knowledge and help to be had here, so you can count on plenty of advice. Make a thread of it, if you have the nerve to learn in public. ;) I by no means consider myself a frame builder, but I'm a pretty decent fabricator, and I'll be glad to help if I can!

    Paying it forward, as it were. :thumbsup:
  • 12-04-2012
    edoz
    I'll third the motion and see it passed. Go ahead and do it, you've got nothing to lose.
  • 12-04-2012
    GrayJay
    Trying to remove the CS from the BB lug without heat does not make much sense. Cut the CS about 1" from the lug and use torch to un-braze it while gently pulling it from the lug. It can also help to use a hacksaw blade to make a cut through length of the remaining stub of the CS (but not so deep that you cut into the lug) releasing any radial fit tension so that the CS can pull out easier.
    If you want to keep the seatstay, just cut the CS first so you are not trying to remove the dropout from both the CS and SS at the same time. Put your heat into the dropout until gravity pulls the DO out of the CS, just be carefull not to get too much heat into the end of the SS or pull aggressivly on the DO while it is hot or it is likely to tear the end of the SS.
  • 12-04-2012
    dr.welby
    Make sure you can get replacement chainstays - those old bikes had some rather unique bending going on.
  • 12-06-2012
    graviT
    Here's some pictures and comments on chainstay replacement by JP Weigle. Pretty amazing how little paint he damaged.

    Make internal cuts to remove stay piece by piece. | Flickr - Photo Sharing!
  • 12-07-2012
    jb9
    Thanks for all the encouragement and helpful suggestions. I actually did see that series of photos from JP Weigle showing how he meticulously removed a chainstay. To be honest, one of the things I was considering was perhaps trying to do all the removal work myself. In other words, if I was able to mechanically remove the rear triangle successfully (since I sort of agree with Mr. Weigle), I feel like I might be more willing to pay a seasoned pro to install a new rear triangle. At least that way, I would know that the most important part of the job would be done right (the brazing). Not to diminish the effort that it would take to build a rear triangle, I was just under the impression that most builders shy away from repairs because they can be messy, might/probably fail in the future and aren't as satisfying as building a new frame. Sorry for introducing the academic discussion... I probably should take Walt's advice and start hacking on some old frames and see how that goes before I would take on something like this.
  • 12-12-2012
    duncaterro
    It should be an elemental enough frame in terms of construction to offer you a reasonable chance at success.