Page 1 of 3 123 LastLast
Results 1 to 20 of 44
Like Tree2Likes

Thread: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

  1. #1
    Tom Gagliardi is offline VSalonistas
    Join Date
    Nov 2011
    Location
    Killingworth, CT
    Posts
    18

    Default Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    As a new frame builder, with no formal training, I've learned some lessons the hard way. I'm just finishing frame #7 and went to thread the BB cups in and realized the BB was backwards. What is really mind blowing is that up to this point I've never considered which way the BB should go...just put it in the jig and built the frame. I can't believe I just got lucky on the first 6 frames, but somehow they all ended up with BB in the right direction.

    OK, what should I do? Just reverse the side on the BB cups and tread in the reverse direction? Try to reverse tap the threads (seams like a dumb idea)?

  2. #2
    mjbabcock is offline VSalonistas
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    1,006

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Is it yours? Just run it. Normal threads are made to loosen if the bearings seize. If your BB goes yours will tighten. If its for a paying customer you need to start over.

    You could also tap it Italian.

  3. #3
    Tom Gagliardi is offline VSalonistas
    Join Date
    Nov 2011
    Location
    Killingworth, CT
    Posts
    18

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Thanks for going easy on my stupidity. No paying customers on frame #7. I think I'll take your advice and just run it (it's for me).

    What would be involved with tapping it Italian?

  4. #4
    seankanary is offline VSalonistas
    Join Date
    Dec 2012
    Location
    AZ
    Posts
    78

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    What direction is the BB supposed to be? I'm about to start my first build and have been thinking about that exact same thing but too embarrassed to ask.

  5. #5
    zetroc is offline VSalonistas
    Join Date
    Apr 2010
    Location
    Alameda, CA
    Posts
    1,685

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Depending on who manufactured your BB shell, it may have an identifying marking telling you which side is the left-hand-thread side (if English threaded.)

    example: www.paragonmachineworks.com - BB00011500x685mm
    steve cortez

    FNG

  6. #6
    echelon_john is offline VSalonistas
    Join Date
    May 2009
    Posts
    977

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    I would recommend against tapping it Italian. Assuming you're running an external bearing bottom bracket, it shouldn't matter at all as far as crankset alignment. If you're running square taper/cartridge, you'll need to make sure it's a symmetrical BB so it doesn't screw up your chainline.

    This is definitely one of those 'measure 3 times, cut once' things. I actually physically thread a BB cup into the shell to verify thread direction, then mark the shell.

    Sean, this only applies to lugless; the shell should be oriented so that the lefty-tighty cup is on the drive side assuming british threading.

  7. #7
    Mark Kelly is offline VSalonista (docendo discimus)
    Join Date
    Aug 2011
    Location
    Willy, VIC
    Posts
    658

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by mjbabcock View Post
    Is it yours? Just run it. Normal threads are made to loosen if the bearings seize.
    The normal explanation given is that the thread directions prevent the cups loosening due to precessive forces.

  8. #8
    veryredbike is offline VSalonistas
    Join Date
    Nov 2011
    Posts
    206

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    In this situation, blue loctite is your friend.

  9. #9
    seankanary is offline VSalonistas
    Join Date
    Dec 2012
    Location
    AZ
    Posts
    78

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by echelon_john View Post

    Sean, this only applies to lugless; the shell should be oriented so that the lefty-tighty cup is on the drive side assuming british threading.
    Thanks. I purchased the bb shells from Nova and there are no identifying marks.

  10. #10
    Mark Kelly is offline VSalonista (docendo discimus)
    Join Date
    Aug 2011
    Location
    Willy, VIC
    Posts
    658

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by seankanary View Post
    What direction is the BB supposed to be?
    The easy mnemonic is BBBB: For British thread, Bottom Bracket is Backwards. Right hand side is left hand thread (and vice versa).

  11. #11
    adarn's Avatar
    adarn is online now VSalonistas
    Join Date
    Aug 2012
    Location
    Bozeman
    Posts
    114

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    I just think about turning the cups towards the axle. I guess there are a lot of ways to remember it though.

  12. #12
    shiggy's Avatar
    shiggy is offline VSalonistas
    Join Date
    Apr 2009
    Location
    Dead Center WA
    Posts
    662

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by thomasauction View Post
    Thanks for going easy on my stupidity. No paying customers on frame #7. I think I'll take your advice and just run it (it's for me).
    You will not be able to use a SRAM GXP BB, though. The non-driveside bearing is smaller diameter.

  13. #13
    seankanary is offline VSalonistas
    Join Date
    Dec 2012
    Location
    AZ
    Posts
    78

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Outstanding, Thanks fellas =)

    --Sorry to hijack your thread Thomas.

  14. #14
    JimFrain's Avatar
    JimFrain is offline VSalonistas
    Join Date
    Dec 2010
    Posts
    31

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    "I guess there are a lot of ways to remember it though." < The threading is the opposite of the pedals.


    "You could also tap it Italian." < Italian Cups are larger so if you try to retap an english cup italian it takes out too much material and could destroy the cup entirely.
    Italian shells are larger diameter, all other size cups fall right through, threads will not engage. - sheldon brown

    I would recommend working in a high volume bike shop as a mechanic for a year or two at least. It will get you acquainted with the mechanics of bicycles and help you answer alot of questions that you might come up with when building a bike. not to mention you will likely test ride a few hundred bikes at least, and that will get you familiar with design versus handling issues. Plus you can get real familiar with components without paying for them.

    Good luck building!
    Jim Frain
    Dharma Cycles
    www.dharmacycles.com

  15. #15
    fortyfour's Avatar
    fortyfour is offline VSalonistas

    Join Date
    Jun 2009
    Location
    Lyndeborough, New Hampshire
    Posts
    1,049

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    This is why I have a drive side bottom bracket cup on hand that lives with my frame jig. I check this constantly so it's oriented correctly. Paragon's bb's have a stepped groove on the drive side (another check point and why I only use Paragon's bottom brackets).
    Kristofer Henry : 44 BIKES : Made to Shred™
    www.44bikes.com · Flickr · Facebook · Instagram · Tumblr

  16. #16
    echelon_john is offline VSalonistas
    Join Date
    May 2009
    Posts
    977

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    that's smart. i'm picturing it hanging on a silver chain that you also fabricated! ; )

    Quote Originally Posted by fortyfour View Post
    This is why I have a drive side bottom bracket cup on hand that lives with my frame jig. I check this constantly so it's oriented correctly. Paragon's bb's have a stepped groove on the drive side (another check point and why I only use Paragon's bottom brackets).

  17. #17
    RyanHeller is offline VSalonistas
    Join Date
    Aug 2012
    Location
    Frisco, Texas
    Posts
    20

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by seankanary View Post
    Thanks. I purchased the bb shells from Nova and there are no identifying marks.
    I am currently building with a Nova BB shell. The drive-side (left-hand thread) has the inside diameter cut larger at the outer most edge before the threads start. That is their identifying mark.

  18. #18
    echelon_john is offline VSalonistas
    Join Date
    May 2009
    Posts
    977

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    I've had Nova shells with the other side cut larger. I think keeping a cup on hand to check and confirm is the best route.

    The other thing I've starter doing with lugless is confirming the orientation of the shell, then immediately drilling the vent holes for the ST, DT and chainstays. Then you've got the holes there to idiot proof multiple fitups and eventual brazing.



    Quote Originally Posted by RyanHeller View Post
    I am currently building with a Nova BB shell. The drive-side (left-hand thread) has the inside diameter cut larger at the outer most edge before the threads start. That is their identifying mark.

  19. #19
    edoz's Avatar
    edoz is offline VSalonistas

    Join Date
    Mar 2009
    Location
    Tulsa, Oklahoma, United States
    Posts
    1,727

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    Quote Originally Posted by fortyfour View Post
    This is why I have a drive side bottom bracket cup on hand that lives with my frame jig. I check this constantly so it's oriented correctly. Paragon's bb's have a stepped groove on the drive side (another check point and why I only use Paragon's bottom brackets).
    I had a scare on my first frame (woke up in the middle of the night and ran out to the garage to check the bb shell) so I set up my fixture to use a modified steel bb cup to center the drive side of the shell on the end of my bb post.

    20130205_202551.jpg
    Eric Doswell, aka Edoz
    Summoner of Crickets
    http://edozbicycles.wordpress.com/
    http://www.flickr.com/photos/edozbicycles/
    In Before the Lock

  20. #20
    artfrank is offline VSalonistas
    Join Date
    Aug 2009
    Posts
    17

    Default Re: Built Frame with Bottom Bracket Backwards - Is it ok to thread cups backwards?

    I built a frame this way by accident once and found that like someone up thread said, blue locate (or red) is your friend. Also with square taper bb, a phil in my case, once the bearings started to fail there was basically no keeping the cups tight for more than about 20 minutes of riding. I still ride that bike regularly though and with good bearings in the bb it hasn't been an issue even when it was set up as a single speed.

Page 1 of 3 123 LastLast

Similar Threads

  1. Bottom Bracket Post
    By ToddFarr in forum The VSalon Frame Forum
    Replies: 65
    Last Post: 03-12-2013, 11:32 PM
  2. FS. NIB Phil Wood bottom bracket cups -French thread
    By TMB in forum Classifieds Classic
    Replies: 0
    Last Post: 06-02-2012, 11:35 AM
  3. New bottom bracket standard - again!
    By Mikej in forum General Discussion
    Replies: 52
    Last Post: 07-20-2011, 11:40 AM
  4. PMP Bottom Bracket?
    By kohlboto in forum General Discussion
    Replies: 0
    Last Post: 04-17-2011, 04:53 PM
  5. Campy bottom bracket cups question
    By Shinomaster in forum General Discussion
    Replies: 11
    Last Post: 04-06-2011, 10:16 PM

Bookmarks

Bookmarks

Posting Permissions

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