Cycling Equipment · Public discussion

source for pedal thread taps?

Started by botfood · · Last activity · 10 posts · 474 views

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Cycling Equipment
Published
6 June 2006
Last activity
7 June 2006
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botfood
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10
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  1. ....still working on setting up kid's cranks on the tandem. the cranks I
    ended up getting are 155mm, and I'd really like to have the 125mm
    option for the 6yr old, and would prefer the more elegant solution of a
    second set of holes for the pedals rather than the external crank
    shorteners....

    I'm not too worried about the 8 yr old overpowering the cranks with the
    extra hole, so am thinking that if i can line up the left/right taps, I
    can get a local machinist to do the job.

    ....so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    thx,
    d

  2. botfood said:

    ...so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    9/16" x 20tpi (most adult bikes)
    1/2" x 20tpi (usually seen in one-piece cranks)

    Park Tool has taps:
    http://tinyurl.com/gfo6y
    and
    http://tinyurl.com/jjpbk

    Tom Ace

  3. Tom Ace said:
    botfood said:

    ...so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    9/16" x 20tpi (most adult bikes)
    1/2" x 20tpi (usually seen in one-piece cranks)
    ------------------------

    amazing... now you have me wondering why the standard thread on pedals
    is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
    that the threads would be cut to some metric size, making the taps hard
    to come by....

    d

  4. botfood said:
    Tom Ace said:
    botfood said:

    ...so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    9/16" x 20tpi (most adult bikes)
    1/2" x 20tpi (usually seen in one-piece cranks)
    ------------------------

    amazing... now you have me wondering why the standard thread on pedals
    is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
    that the threads would be cut to some metric size, making the taps hard
    to come by....

    d

    remember that the left crank is left-hand thread.

    Pedal threads are about the most standardized things about bike parts.
    Sheldon has a good explaination in his glossary:
    http://www.sheldonbrown.com/gloss_p.html

    Jeff

  5. JeffWills said:

    remember that the left crank is left-hand thread.
    Pedal threads are about the most standardized things about bike parts.
    Sheldon has a good explaination in his glossary:
    http://www.sheldonbrown.com/gloss_p.html
    ----------------------

    I understand the left/right, but am amazed that the thread diameter and
    pitch remains english while virtually every other part, thread, nut and
    bolt on bikes is metric.

    d

  6. botfood said:

    ...still working on setting up kid's cranks on the tandem. the cranks I
    ended up getting are 155mm, and I'd really like to have the 125mm
    option for the 6yr old, and would prefer the more elegant solution of a
    second set of holes for the pedals rather than the external crank
    shorteners....

    I'm not too worried about the 8 yr old overpowering the cranks with the
    extra hole, so am thinking that if i can line up the left/right taps, I
    can get a local machinist to do the job.

    ...so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    We've got 'em: http://sheldonbrown.com/harris/tools/tap.html

    If you do this, I strongly advise you to cut off the ends of the cranks
    so nobody will be tempted to use the original holes for an adult at some
    later time.

    You might also want to consider using the smaller (1/2"😉 size and buying
    appropriate pedals.

    Sheldon "Stokid" Brown
    +------------------------------------------------+
    | Love at its best means marriage, and it is |
    | altogether the most beautiful thing in life |
    | -- William Dean Howells |
    +------------------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com

  7. botfood said:


    Tom Ace said:
    botfood said:

    ...so, anybody have a source for the taps, or know the exact specs
    (thread/pitch) so i can look them up in a tool catalog?

    9/16" x 20tpi (most adult bikes)
    1/2" x 20tpi (usually seen in one-piece cranks)
    ------------------------

    amazing... now you have me wondering why the standard thread on pedals
    is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
    that the threads would be cut to some metric size, making the taps hard
    to come by....

    They're still hard to come by. That's not a standard thread pitch for
    either the 1/2" or the 9/16" diameter. And then there's the left-hand
    thread on one side...
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.

  8. botfood said:


    JeffWills said:

    remember that the left crank is left-hand thread.
    Pedal threads are about the most standardized things about bike parts.
    Sheldon has a good explaination in his glossary:
    http://www.sheldonbrown.com/gloss_p.html
    ----------------------

    I understand the left/right, but am amazed that the thread diameter and
    pitch remains english while virtually every other part, thread, nut and
    bolt on bikes is metric.

    The pedal threads were standardized a very long time ago, and the only
    recent change was to use metric spacing on the wrench flats.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.

  9. botfood said:
    JeffWills said:

    remember that the left crank is left-hand thread.
    Pedal threads are about the most standardized things about bike parts.
    Sheldon has a good explaination in his glossary:
    http://www.sheldonbrown.com/gloss_p.html
    ----------------------

    I understand the left/right, but am amazed that the thread diameter and
    pitch remains english while virtually every other part, thread, nut and
    bolt on bikes is metric.

    d

    Well... Campy axles are 26tpi (threads per *inch*). It's a long story
    that's been posted before.

    And *don't* get started on tire sizes!

    Jeff

  10. Sheldon Brown said:
    botfood said:

    ...still working on setting up kid's cranks on the tandem.


    ....

    Quoted message said:

    We've got 'em: http://sheldonbrown.com/harris/tools/tap.html
    You might also want to consider using the smaller (1/2"😉 size and buying
    appropriate pedals.
    -------

    looks good, I'll check my stock of tiny bikes, I am pretty sure at
    least one of them has the 1/2 pedals, which would leave a little more
    meat on the crank....

    d

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