Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    Senior Member
    Join Date
    May 2010
    Posts
    461
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    classic crank threads

    I have a late 70s classic with Campagnolo components. The original Campy pedals mount easily on the Campy cranks, but I can't use them (too small). When I try some current pedals, I find some thread on cleanly and others just don't want to go. For example, I have a pair of MKS Sylvan touring pedals of which the right one installs nicely but the left meets heavy resistance halfway in. There's no junk in the threads getting in the way.

    I suppose a good shop would have taps (left and right threaded) that might be used to clean up these threads. I find it strange though that the orignal pedals go on easily.

    Have threading standards changed, or were threads just not as accurate back in the 70s?


    [update] I cleaned out the crank threads (again), put TriFlow on the MKS pedal threads and cranked them in with a sizeable pedal wrench. They didn't seem to be as happy about it as I would like, but I blew past the resistance and they threaded in all the way. Just a question of accuracy in the machining of either the cranks or the pedals I guess.
    Last edited by jim hughes; 08-26-11 at 04:00 PM.

  2. #2
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    24,841
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Yeah, I don't think pedal thread standards (9/16"x20 tpi for good quality bikes) have changed for many decades and AFAIK, there aren't any differing ISO/JIS type standards either. The fact the right MKS pedal went in with no difficulty says the pitch and diameter are the same as your older Campy pedals.

  3. #3
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    18,200
    Mentioned
    20 Post(s)
    Tagged
    1 Thread(s)
    As Hillrider said, there has only been one standard in use throughout the world (except France (figures)) for many decades. However even within the same standard there is tolerance, so there will be some variation in fit. When Campagnolo started aluminum cranks they elected to keep the thread nearer to the lower size limit (as did other alloy crank makers) to ensure a tighter fit. It makes sense because aluminum threads have less strength than the same threads in steel, so good fit is more important.

    Odds are that your other pedals have slightly larger pitch diameters (how to measure) and so are just that extra bit too tight. I suggest you check that there are no dinged threads, and if not, grease them and gently force them in. Don't get carried away, and if the force needed is significant, or ramps up as you go deeper, stop.

    It's barely possible that your Campy cranks were made for the French market and have the 14mm thread rather than the BSC/ISO thread.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  4. #4
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    24,841
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    It's barely possible that your Campy cranks were made for the French market and have the 14mm thread rather than the BSC/ISO thread.
    Well, the OP said the right side pedal threaded in with no resistance or problems so I expect the threads are the correct configuration and the left pedal problem is just tolerances.

  5. #5
    Senior Member
    Join Date
    May 2010
    Posts
    461
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    As I updated above, I got them in and I don't think there was any damage in doing so. I've actually installed a different pair of new pedals in those cranks before without this resistance. So yes, I think it's just tolerance and materials.

  6. #6
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    18,200
    Mentioned
    20 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by HillRider View Post
    Well, the OP said the right side pedal threaded in with no resistance or problems so I expect the threads are the correct configuration and the left pedal problem is just tolerances.
    I agree, but when I tell someone I don't know, to force something I didn't see, I always try to give them a reason not to go crazy.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  7. #7
    Senior Member
    Join Date
    Jul 2008
    Posts
    1,229
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    As Hillrider said, there has only been one standard in use throughout the world (except France (figures)) for many decades.

    No, there was an Italian pedal thread. It's, in true insane italian fashion, 9/16" X 20 tpi, with, like you'd expect, Whitworth thread form. 55 degrees, rounded roots and crests, instead of the 60 degree thread that everyone else used. A tap, or just a bunch of force, will get them to take a standard pedal.

    OP: examine your original pedals; if they're Italian threaded, there's a good chance they'll say "D" on the right one, and "S" of the left.

  8. #8
    Insane Bicycle Mechanic Jeff Wills's Avatar
    Join Date
    Mar 2008
    Location
    other Vancouver
    Posts
    6,424
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dscheidt View Post
    No, there was an Italian pedal thread. It's, in true insane italian fashion, 9/16" X 20 tpi, with, like you'd expect, Whitworth thread form. 55 degrees, rounded roots and crests, instead of the 60 degree thread that everyone else used. A tap, or just a bunch of force, will get them to take a standard pedal.

    OP: examine your original pedals; if they're Italian threaded, there's a good chance they'll say "D" on the right one, and "S" of the left.
    +1. I have a set of Campy cranks (de-anodized and polished Campy BMX) that I used with Shimano clipless pedals for many years. The pedals were always tough to install and remove- they were impossible to thread on without a wrench. I never saw any damage in the threads of the cranks so they're probably OK.
    Jeff Wills

    All my bikes.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •