Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    Senior Member
    Join Date
    Jul 2005
    Location
    Seattle
    My Bikes
    Giant TCR2
    Posts
    474
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    BB Question - Italian Threading but not 70 mm wide?

    I am converting a frame that has a threadless bottom bracket, which I am in the process of threading. But I'm not sure what my options are since my last conversion was far more straightforward (english treaded off the bat). I don't think English/ISO threads will fit, but it is likely that Italian threads will fit (slightly bigger). The thing is, the BB shell width is 68 mm, so the Italian (70mm) would leave a 2mm gap...is that likely to be a problem? Hopefully I can leave the gap on the non drive side so as to not screw up the chainline? Or is it possible to use Italian cups with a English 68 mm bottom bracket cartridge with the proper spindle length? I know I need a 107mm BB for the proper chainline. This BB stuff is getting me pretty confused, so any help sorting it out would be greatly appreciated.

  2. #2
    () space_robots's Avatar
    Join Date
    Feb 2006
    Location
    Seattle
    Posts
    187
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    How old is the frame and where was it made? I can't imagine it being too large for ISO threads if the width is 68mm. Unless it's really old, and it was designed for French or Swiss BBs (which are also 68mm width). I don't know if French/Swiss where slightly larger though, they might have been the same size as the ISO.

    Anyway, the 2mm would probably be acceptable, but I would go for the ISO first. If it doesn't work out, you can always tap out to the Italian threads.

  3. #3
    Senior Member
    Join Date
    Jul 2005
    Location
    Seattle
    My Bikes
    Giant TCR2
    Posts
    474
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It's an English-made Viscount, Late 70's. From my crude measurements the ISO won't fit, but I think I'm going to take it to a shop and have it checked out since this is going to be a close call. It looks like the bearings are 35mm OD, English threads are ~34.9mm. Italian is 36mm. It's such a cool frame I'm hoping this wont be a big pain!

  4. #4
    Glorified Blender mikearena's Avatar
    Join Date
    Aug 2005
    Location
    Arlington, VA
    Posts
    686
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Matthew A Brown has a Medici with Italian threads, but a 68 mm shell. Ask him what he did, because I know he's got it up and running just fine.

  5. #5
    MADE IN HONG KONG
    Join Date
    Aug 2005
    Location
    Washington DC
    My Bikes
    some but not enough
    Posts
    1,763
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Have you considered adding a 1mm spacer on the fix cup side?
    If you are not having any fun, it's all your fault

  6. #6
    re:member
    Join Date
    Jan 2005
    Location
    Cracow, Poland
    My Bikes
    unknown make TT bike, fixed; Romet Sport, gone; titanium Pinarello gone;Colnago with Campy C-Record/Super Record,on it's way; Funny Gianni Motta; Buehler track, Polrad track chrome; titanium MTB on 28'', fixed; Tri Wheeler, fixed
    Posts
    874
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by iansir
    I am converting a frame that has a threadless bottom bracket, which I am in the process of threading. But I'm not sure what my options are since my last conversion was far more straightforward (english treaded off the bat). I don't think English/ISO threads will fit, but it is likely that Italian threads will fit (slightly bigger). The thing is, the BB shell width is 68 mm, so the Italian (70mm) would leave a 2mm gap...is that likely to be a problem? Hopefully I can leave the gap on the non drive side so as to not screw up the chainline? Or is it possible to use Italian cups with a English 68 mm bottom bracket cartridge with the proper spindle length? I know I need a 107mm BB for the proper chainline. This BB stuff is getting me pretty confused, so any help sorting it out would be greatly appreciated.
    I have two bikes formerly belonging to pros. Both of them have Italian BBs, one has 68mm shell spaced out to 70mm by washers. Funny thing is there is one washer on each side of the shell. Usually, you can space out the hub, too if there is a problem with the chainline.

  7. #7
    Senior Member
    Join Date
    Jul 2005
    Location
    Seattle
    My Bikes
    Giant TCR2
    Posts
    474
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the suggestions everyone! After I finish I'll let you know what worked on the build.

  8. #8
    Cornucopia of Awesomeness baxtefer's Avatar
    Join Date
    Oct 2004
    Location
    not where i used to be
    Posts
    4,847
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    1mm spacer on each side, or have you seen this.....

    http://bikecult.com/works/parts/bbViscount.html

    make sure you get rid of the death fork
    {o,o**
    |)__)
    -"-"-

    O RLY?

Posting Permissions

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