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Frame mods: crimping chainstays?

Started by Ryan Cousineau · · Last activity · 7 posts · 903 views

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01 / Original postFrame mods: crimping chainstays?Ryan Cousineau · 29 May 2006 02 / This pagePosts 1–7Page 1 of 1 · chronological order 03 / Latest replyPost #7Ryan Cousineau · 31 May 2006

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Original section
Cycling Equipment
Published
29 May 2006
Last activity
31 May 2006
Original author
Ryan Cousineau
Posts
7
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Public discussion
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903
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Topics
Cyclocross

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  1. Original post
    Ryan Cousineau
    Archived post
    #1

    So I have an innocent steel Pinarello frame sitting in The Pile, and
    I've been moderately desperate to upgrade my current "cyclocross" bike,
    a hideously converted Motobecane tourer that may be older than me.

    The Pinarello's fate was sealed when I realized it had a top-mounted
    rear brake cable run. Hello cyclocross!

    So some experiments with my preferred 32 mm tire (WTB Terrainasaurus)
    shows that said tire will...juuust fit into the frame. It doesn't quite
    hit the brake arch, and it sorta just whispers against the chainstay at
    the wheel's worst wobble.

    That's not good, but here's my two-step solution:

    1) file the dropouts as much as I dare: I can probably add 1-2 mm to the
    dropouts, and by doing so, should make sure the brake arch never comes
    in contact with the tire, and gain a bit of room between the chainstays

    2) the chainstays have no clearance crimps, as are common on lots of
    frames. So, how can I add some? My theory is that wood blocks and heavy
    clamps are the preferred method of doing this, but if there's a good way
    to crimp the tubes of an already-constructed frame, I'm all ears.

    Any other suggestions? I expect to run a standard-reach single-pivot
    brake on the back to maximize clearance when I'm done, and I've accepted
    that I'm going to lose some paint to mud in the messy going, but if the
    wheel will turn, this should be a really acceptable 'cross machine.

    I realize that the going rate for good cyclocross frames online is
    $150-300, but my budget for a new frame is more like $75 plus shipping.

    Thanks in advance,

    --
    Ryan Cousineau [email hidden] http://www.wiredcola.com/
    "I don't want kids who are thinking about going into mathematics
    to think that they have to take drugs to succeed." -Paul Erdos

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  2. Email address hidden
    Archived post
    #2
    Ryan Cousineau said:

    So some experiments with my preferred 32 mm tire (WTB Terrainasaurus)
    shows that said tire will...juuust fit into the frame. It doesn't quite
    hit the brake arch, and it sorta just whispers against the chainstay at
    the wheel's worst wobble.

    If it's clean and a tight fit, it may jam into the frame (or at least
    severely slow you down) when muddy... I'd say add at least 5mm (1/4"😉
    clearance to avoid that.

    I'm not a framer, but I would think adding 5mm clearance with such
    methods might ruin the frame, specially in a cyclocross use with many
    bumps stressing the frame and dropouts?

    Report
  3. Email address hidden
    Archived post
    #3

    Dear Ryan & list:

    I've done a few of these mods. They work best with a frame that is
    made of plain-vanilla (not heat treated) cro-moly. I like the
    '70s-vintage Schwinn 12.2 super le tours, back when they were made by
    Bridgestone.

    With a good, heavy chainstay, you can cold-crimp or "heat it and beat
    it" to increase tire clearance. Don't do this with a thin-wall, heat
    treated stay. You don't say which model Pinarello you have, but
    whatever it is, I would suggest selling it as-is or trading for
    something a little less sharp-handling and a little more substantial.
    The Japanese-made Raleigh Internationals for instance are abundant ....

    good luck

    jn

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  4. Bob
    Archived post
    #4
    Quoted message said:

    Japanese-made Raleigh

    I hate seeing those three words together.

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  5. Email address hidden
    Archived post
    #5
    Ryan Cousineau said:

    So I have an innocent steel Pinarello frame sitting in The Pile, and
    I've been moderately desperate to upgrade my current "cyclocross" bike,
    a hideously converted Motobecane tourer that may be older than me.

    The Pinarello's fate was sealed when I realized it had a top-mounted
    rear brake cable run. Hello cyclocross!

    So some experiments with my preferred 32 mm tire (WTB Terrainasaurus)
    shows that said tire will...juuust fit into the frame. It doesn't quite
    hit the brake arch, and it sorta just whispers against the chainstay at
    the wheel's worst wobble.

    Use a slightly smaller tire in back.
    You have horizontal dropouts, right? I don't think filing them
    is going to help much with clearing the brake arch anyway,
    because the dropouts are slanted.

    In real muddy conditions, this bike's going to pack up anyway,
    extra couple of mm of clearance or not. But you might make
    it work for dry-ish conditions, depending on what passes for
    dry in the Pacific Northwet.

    Report
  6. Donald Gillies
    Archived post
    #6
    Ryan Cousineau said:

    So I have an innocent steel Pinarello frame sitting in The Pile, and
    I've been moderately desperate to upgrade my current "cyclocross" bike,
    a hideously converted Motobecane tourer that may be older than me.

    Do you really want to do this to a classic pinarello frameset ?? Why
    not start with a used $5 tange ebay frameset from nashbar or
    performance bike in the 1980's. A pinarello is ... a classic!

    - Don Gillies
    San Diego, CA

    Report
  7. Ryan Cousineau
    Archived post
    #7

    In article <[email hidden]>,

    (Donald Gillies) said:
    Ryan Cousineau said:

    So I have an innocent steel Pinarello frame sitting in The Pile, and
    I've been moderately desperate to upgrade my current "cyclocross" bike,
    a hideously converted Motobecane tourer that may be older than me.

    Do you really want to do this to a classic pinarello frameset ?? Why
    not start with a used $5 tange ebay frameset from nashbar or
    performance bike in the 1980's. A pinarello is ... a classic!

    The good news is that it's not that classic. More like early 90s,
    entry-level (but still very good) Pinarello.

    The better news is that I'm abandoning the project. I have a more
    suitable bike, a Bianchi.

    --
    Ryan Cousineau [email hidden] http://www.wiredcola.com/
    "I don't want kids who are thinking about going into mathematics
    to think that they have to take drugs to succeed." -Paul Erdos

    Report

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