Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

BB thread stripped, how to fix?

Search
Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

BB thread stripped, how to fix?

Thread Tools
 
Search this Thread
 
Old 04-06-10 | 04:39 PM
  #1  
Thread Starter
Mamut
 
Joined: Aug 2008
Posts: 6
Likes: 0
From: Ridgewood, Queens

Bikes: Schwinn 700c

BB thread stripped, how to fix?

i dont know how this happened but the thread is stripped on the BB in the frame. is there a fix to this? threadless BB? how can a stripped thread be fixed on the frame?
mamut is offline  
Reply
Old 04-06-10 | 05:00 PM
  #2  
Senior Member
 
Joined: Feb 2009
Posts: 6,660
Likes: 177
https://www.biketoolsetc.com/index.cg...r-Spindle&q=&s=
davidad is offline  
Reply
Old 04-06-10 | 05:31 PM
  #3  
Thread Starter
Mamut
 
Joined: Aug 2008
Posts: 6
Likes: 0
From: Ridgewood, Queens

Bikes: Schwinn 700c

thank you
mamut is offline  
Reply
Old 04-06-10 | 07:24 PM
  #4  
Senior Member
 
Joined: Dec 2005
Posts: 7,848
Likes: 4
U can rethread the BB anyways. If the BB was english u can go to italian threading. If the frame is aluminum u can use the ALuminum magic rod and rethread the BB also.
ultraman6970 is offline  
Reply
Old 04-07-10 | 01:20 AM
  #5  
cnnrmccloskey's Avatar
Senior Member
 
Joined: May 2009
Posts: 744
Likes: 0
From: Portland Oregon

Bikes: '82 Giante super challange, 70 Gitane Tour de France, GT Gutterball

https://www.velo-orange.com/grcruthbobr.html
Velo-Orange makes one too.
cnnrmccloskey is offline  
Reply
Old 04-07-10 | 04:06 AM
  #6  
Kimmo's Avatar
Senior Member
 
Joined: Dec 2009
Posts: 9,563
Likes: 736
From: Melbourne, Oz

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Originally Posted by ultraman6970
If the frame is aluminum u can use the ALuminum magic rod and rethread the BB also.
What's the deal with that?

I have a nice ally frame with a stripped BB...
Kimmo is offline  
Reply
Old 04-07-10 | 06:30 PM
  #7  
Senior Member
 
Joined: Dec 2005
Posts: 7,848
Likes: 4
There is an aluminum rod that i cant remember the name right now, u can heat it with a basic mapp torch kit... Once is hot is like applying electrical soldering stuff... so heat the area the stuff will melt, cover the threads and then rethread again. done. since is nothing structural is not a problem to use it. The problem comes when somebody wants to use this to fix a broken frame, it will work but the frame will brake in another place because there is a heat treatment that needs to be done to the whole frame after the welding.

Here it goes... https://www.durafix.com/
ultraman6970 is offline  
Reply
Old 04-07-10 | 06:41 PM
  #8  
Senior Member
 
Joined: Dec 2009
Posts: 4,700
Likes: 5
Originally Posted by ultraman6970
There is an aluminum rod that i cant remember the name right now, u can heat it with a basic mapp torch kit... Once is hot is like applying electrical soldering stuff... so heat the area the stuff will melt, cover the threads and then rethread again. done. since is nothing structural is not a problem to use it. The problem comes when somebody wants to use this to fix a broken frame, it will work but the frame will brake in another place because there is a heat treatment that needs to be done to the whole frame after the welding.

Here it goes... https://www.durafix.com/
The bottom bracket threads aren't structural?

Of course they are.

All those thread do is hold the crankset while you're hammering away on the pedals. They're taking a LOT of stress when they're doing that.
achoo is offline  
Reply
Old 04-07-10 | 06:56 PM
  #9  
Senior Member
 
Joined: Dec 2005
Posts: 7,848
Likes: 4
Yes i understand what you say, but i believe u are taking what im saying literally and you don't see what i'm saying yet. Besides arent the threads the ones that are taking all the stress but the whole shell. U are repairing the threads to get the BB into the shell. The shell wont have any problem after is rethreaded using the durafix rod.

But if you have the bad idea of reparing an old aluminum frame that got a problem (crack) in a welding for example in the joint of the TT and the Head tube, the durafix will work and will get the thing repaired pretty good, so good that the frame will crack in another place because the new welding is stronger than any welding in the frame. Durafix works awesome to repair threads in bikes. But not for repairing cracks.

There is a guy with a marin frame with that problem right now, look at the thread, I didnt even mention the product because will be a waste, aluminum frame with a nasty crack.

U can repair aluminum frames pretty easily and at home with this product, but if you dont have where to apply the heat treatment to the frames after wards the fix will be a waste because the frame will brake again warrantied probably next to the repair.

ultraman6970 is offline  
Reply
Old 04-07-10 | 07:00 PM
  #10  
JohnDThompson's Avatar
Old fart
Titanium Club Membership
20 Anniversary
Community Builder
 
Joined: Nov 2004
Posts: 26,361
Likes: 5,271
From: Appleton WI

Bikes: Several, mostly not name brands.

Originally Posted by achoo
The bottom bracket threads aren't structural?

Of course they are.

All those thread do is hold the crankset while you're hammering away on the pedals. They're taking a LOT of stress when they're doing that.
Yup. And even the heat from the MAPP gas torch will compromise the frame's heat treatment and strength in that area. The bottom bracket is the most complex joint on the frame -- four tubes come together there. Compromising the heat treatment in that area is not something I'd advise.
JohnDThompson is offline  
Reply
Old 04-07-10 | 07:09 PM
  #11  
Senior Member
 
Joined: Dec 2005
Posts: 7,848
Likes: 4
Cant remember who have done it here in the forums with aluminum. We have done it with steel anyways. The temperature is not even that extreme, the rod melts too fast to damage anything else at all. But well
ultraman6970 is offline  
Reply
Old 04-08-10 | 01:45 AM
  #12  
fuzz2050's Avatar
Real Men Ride Ordinaries
 
Joined: Sep 2008
Posts: 3,723
Likes: 3
Originally Posted by ultraman6970
Cant remember who have done it here in the forums with aluminum. We have done it with steel anyways. The temperature is not even that extreme, the rod melts too fast to damage anything else at all. But well
Sweet at that 'magic rod' is, no need to risk it when a $20 bottom bracket will do the job just as well.
fuzz2050 is offline  
Reply
Old 04-08-10 | 07:55 AM
  #13  
Senior Member
 
Joined: Dec 2005
Posts: 7,848
Likes: 4
Well if you have outboard cranksets and one expensive frame with a problem, i doubt a 20 dols bb will do at all. Thats the reason maybe kimmo asked also.
ultraman6970 is offline  
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
chagheill
Singlespeed & Fixed Gear
8
09-01-15 08:46 PM
Cyclist0383
Singlespeed & Fixed Gear
0
06-29-14 04:00 PM
ebgbz
Bicycle Mechanics
9
03-03-13 08:15 AM
TL179
Classic & Vintage
21
11-26-10 06:47 PM
bgblue1978
Bicycle Mechanics
4
05-10-10 07:41 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.