Cycling Equipment · Public discussion

Re: Bolt Hole Circles

Started by James Thomson · · Last activity · 4 posts · 384 views

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Cycling Equipment
Published
27 December 2004
Last activity
27 December 2004
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James Thomson
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  1. !Jones said:

    When you're talking about a bolt hole pattern on a chain
    ring, you specify the radius and # of teeth, correct?

    Normally the bolt circle _diameter_ and number of teeth.

    Quoted message said:

    The tandem timing ring has 32 teeth. The 5 holes measure about
    29mm on center. Solving for the radius of the bolt hole circle, I get
    24.67mm; however, I see nothing like that in any of the catalogs.
    Am I on the right sheet of music here?

    Is it a TA Cyclotourist (Pro 5 vis), Stronglight 49D, or one of many older
    cranks that used a 50mm primary bolt circle? If so, TA rings are still
    available. In the USA, try Peter White Cycles or Harris Cyclery (Google
    will find you their web sites).

    James Thomson

  2. !Jones said:

    Peter White just said in an e-mail that he has never heard of
    a 50mm BC!

    If you'd said TA pro 5 vis tandem timing rings, he would have understood
    right away. But in any case, my advice was bad. Peter White says:

    "I haven't stocked any Pro 5 Vis arms, chainrings or bottom brackets in
    years."

    http://www.peterwhitecycles.com/zephyr.asp

    Quoted message said:

    Oh, well. I have a mill so I suppose I can drill out a blank.

    No need. Harris Cyclery can still help:

    http://www.sheldonbrown.com/harris/french-cranks.html#chainwheels

    so can these guys:

    http://www.tandemseast.com/chain.html

    James Thomson

  3. !Jones wrote:
    -snip-

    Quoted message said:

    Peter White just said in an e-mail that he has never heard of a 50mm
    BC! Oh, well. I have a mill so I suppose I can drill out a blank.

    Perhaps a different approach? If Peter White says he's
    never heard of a 50mm ring ( me neither) it probably is
    _not_ a 50mm ring!

    Why don't you just come right out and tell us what bike it
    is, year and model , and any markings on the cranks or
    chainrings? It would be so much quicker.

    Earlier you asked about brakes on your Suntour-equipped
    tandem, than a half-hour later said they were Mafac. It
    doesn't help to be cryptic!

    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971

  4. !Jones said:

    On Sun, 26 Dec 2004 21:05:04 -0600 in
    <[email hidden]>
    A Muzi <[email hidden]> said this:

    Quoted message said:

    Why don't you just come right out and tell us what bike it
    is, year and model , and any markings on the cranks or
    chainrings? It would be so much quicker.

    It's an old Santana I picked up in a garage sale. I suspect it's an
    '84 model or thereabouts. It's a chromoly frame, so it can't be any
    older and, with the components it has, it's not any younger. It has
    Suntour shifters and Mafac brakes. It also has a "child stoker kit"
    installed which I'm going to remove and toss; however, this kit
    introduced some spacing issues on the stoker timing ring... i.e., it's
    a longer spindle.

    You know, you're not under any *obligation* to help; I will manage to
    muddle through somehow. OTOH, your advice is valued and appreciated.
    I wasn't trying to obfuscate; I just didn't think anyone would really
    want to hear the details of the junker I found.

    (BTW, if anyone out there in Usenet-land happens to have their heart
    set on a 50mm set up child stoker kit for an old tandem that uses TA
    cranks, then now is the time to ask... it's incomplete.)

    Jones

    Such a nice bike! Everyone has an opinon.Here's mine.

    I'd redo those brakes with modern cables and Kool Stop shoes
    and ride it.

    If you _and your companion_ find the fit, handling and the
    concept of tandeming all to your taste, redo the gear system
    later to something modern. That shouldn't keep you from
    riding. There are some technical issues that make it
    expensive because it's hard to do a partial gear system upgrade.

    Everything you own is of good quality, assuming it isn't
    worn out. So don't obsess over the details. Just ride for a
    season and then worry about upgrades.

    http://www.yellowjersey.org/photosfromthepast/SGSANTAN.JPG

    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971

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