Advertise on Bikeforums.net



User Tag List

Results 1 to 7 of 7
  1. #1
    seņor member seaneee's Avatar
    Join Date
    Jun 2006
    Location
    yay area
    My Bikes
    Malvern Path Racer, Schwinn LeTour, Follis, Bridgestone 400 (RIP), concord 2sp
    Posts
    1,157
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    68mm BB in 70mm Shell?

    I posted this in another forum, but I hoping to get a more exact answer here.

    I have an old 70's Concord. It has a 70mm BB shell, but it's english thread. Could I make a 68mm bottom bracket work? Or even a 73mm? Any ideas? Thanks.

  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
    26,176
    Mentioned
    14 Post(s)
    Tagged
    0 Thread(s)
    If you are going to use a Shimano UN-7X or UN-5X square taper cartridge bb, you can probably just get a 68 mm one and screw the nds cup in the extra 2mm since that cup doesn't shoulder against the bb shell

  3. #3
    no brakes,no problem! -Blanco-'s Avatar
    Join Date
    Jul 2006
    Location
    Dublin, Ireland
    My Bikes
    dolan track bike,trek 5500, trek 7000 zx, giant stp
    Posts
    62
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I had the same problem, I used a 68mm bb and tightend...it works fine for me
    "Everyone makes mistakes, the trick is to make the mistakes when nobodys looking"

  4. #4
    Senior Member Nessism's Avatar
    Join Date
    Jun 2004
    Location
    Torrance, CA
    My Bikes
    Homebuilt steel
    Posts
    2,324
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Get the BB shell faced down to 68 mm. Make sure both sides of the shell are symetric or your chain line will be off.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

    Good/Bad Trader Listing

  5. #5
    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
    26,176
    Mentioned
    14 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Nessism
    Get the BB shell faced down to 68 mm. Make sure both sides of the shell are symetric or your chain line will be off.
    That can be done but it's a lot of metal to remove and the LBS is going to charge a fair bit to cover the wear and tear on his facing tool. A '70's concord probably isn't worth what it will cost.

    The Shimano 68 mm square taper cartridge bottom brackets I recommended will fit with no modifications and a 1 mm "error" in the chain line is a non-issue.

  6. #6
    Senior Member Nessism's Avatar
    Join Date
    Jun 2004
    Location
    Torrance, CA
    My Bikes
    Homebuilt steel
    Posts
    2,324
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HillRider
    That can be done but it's a lot of metal to remove and the LBS is going to charge a fair bit to cover the wear and tear on his facing tool. A '70's concord probably isn't worth what it will cost.
    It won't cost much, if any, more to have the shell cut down to the proper size. I've faced a fair number of shells before and the cutter will shave a couple mm's of material pretty quickly.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

    Good/Bad Trader Listing

  7. #7
    seņor member seaneee's Avatar
    Join Date
    Jun 2006
    Location
    yay area
    My Bikes
    Malvern Path Racer, Schwinn LeTour, Follis, Bridgestone 400 (RIP), concord 2sp
    Posts
    1,157
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Nessism
    It won't cost much, if any, more to have the shell cut down to the proper size. I've faced a fair number of shells before and the cutter will shave a couple mm's of material pretty quickly.
    actually it looks like it wont work. I took a closer look at the shell and the chainstays are REALLY close. I would be concerned with strenth issues even with 1mm. Nashbar has a $5 bb i may try or I may have the threads removed an go with a YST that will fit both 68 and 70mm, both pretty inexpensive options.

Posting Permissions

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