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

Broken downtube to bottom bracket - can it be safely repaired?

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.

Broken downtube to bottom bracket - can it be safely repaired?

Old 04-07-21, 12:24 PM
  #1  
Air
Destroyer of Wheels
Thread Starter
 
Air's Avatar
 
Join Date: May 2006
Location: Creating some FA-Qs
Posts: 3,531

Bikes: Surly LHT, Dahon folding bike. RIP Nishiki Sport, Downtube IXNS, 1950's MMB3 Russian Folding Bike, MTB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 6 Times in 4 Posts
Broken downtube to bottom bracket - can it be safely repaired?

This seems terminal. I saved my Nishiki Sport from a backyard in 2006 and built it up over the years through hours of browsing threads here. Only fitting to get a final opinion from where it was born from. I'm a high Clydesdale (used to be mid...thanks Covid), this is the second time a part of the frame broke (the first was where the chainstay met the rear wheel). Took me a few miles to figure out where the knocking was coming from, looked down, gut punch.

Open to any thoughts, thanks!




__________________
The Almighty Clyde FAQ || Northeast Index
eTrex Vista References || Road Reference


It's the year of the enema!
Air is offline  
Old 04-07-21, 12:48 PM
  #2  
Trakhak
Senior Member
 
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 2,756
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 700 Times in 410 Posts
You might want to ask the mods to move this thread to the Framebuilders section of the forum.

That said, that's probably not the only joint that was close to failure---it's just the joint that happened to fail first. Same applies to the first broken chainstay.
Trakhak is online now  
Old 04-07-21, 01:31 PM
  #3  
Air
Destroyer of Wheels
Thread Starter
 
Air's Avatar
 
Join Date: May 2006
Location: Creating some FA-Qs
Posts: 3,531

Bikes: Surly LHT, Dahon folding bike. RIP Nishiki Sport, Downtube IXNS, 1950's MMB3 Russian Folding Bike, MTB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 6 Times in 4 Posts
Yeah...that's my thought too. It was in a backyard for a few years, metal fatigue doesn't usually get better over time and NYC streets aren't kind.

Good thought about the Framebuilder section, thanks!
__________________
The Almighty Clyde FAQ || Northeast Index
eTrex Vista References || Road Reference


It's the year of the enema!
Air is offline  
Likes For Air:
Old 04-07-21, 02:20 PM
  #4  
veganbikes
Clark W. Griswold
 
Join Date: Mar 2014
Location: ,location, location
Posts: 8,658

Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), Cilo Road Frame, Proteus frame, Ti 26 MTB

Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 2388 Post(s)
Liked 1,388 Times in 933 Posts
I mean do you really want to save a backyard find that isn't a super high end bike? It is up to you. It might be saved but it will probably cost more than the bike is worth and it sounds like you have put some time on it so it might be time to let it go. Especially as a Clyde you don't want to risk it over that.
veganbikes is offline  
Old 04-07-21, 03:51 PM
  #5  
Air
Destroyer of Wheels
Thread Starter
 
Air's Avatar
 
Join Date: May 2006
Location: Creating some FA-Qs
Posts: 3,531

Bikes: Surly LHT, Dahon folding bike. RIP Nishiki Sport, Downtube IXNS, 1950's MMB3 Russian Folding Bike, MTB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 6 Times in 4 Posts
Originally Posted by veganbikes View Post
I mean do you really want to save a backyard find that isn't a super high end bike? It is up to you. It might be saved but it will probably cost more than the bike is worth and it sounds like you have put some time on it so it might be time to let it go. Especially as a Clyde you don't want to risk it over that.
Well...worth is subjective, right? I spent over a year dialing it in till it was perfect, where 80 mile rides didn't feel much longer than 30 and put thousands into it over the years. What's that time, sunk cost, comfort, and familiarity "worth"? A lot...to me! It was my fourth bike, and the only one I could get to feel like a body part while riding. I figure a new bike will require the same energy to get to hopefully about the same level. If there was an easy fix, it would be worth it.

But I agree with you, if the only solution was essentially disassembling the frame and machining a new BB only to worry where the next point of failure will crop up, it's better to start putting effort into something new.
__________________
The Almighty Clyde FAQ || Northeast Index
eTrex Vista References || Road Reference


It's the year of the enema!
Air is offline  
Old 04-07-21, 04:58 PM
  #6  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 7,797

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 1656 Post(s)
Liked 1,288 Times in 839 Posts
this was a Lotus with a similar failure repaired by a local motorcycle shop




dedhed is offline  
Likes For dedhed:
Old 04-07-21, 05:01 PM
  #7  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 22,705

Bikes: Several, mostly not name brands.

Mentioned: 133 Post(s)
Tagged: 0 Thread(s)
Quoted: 2639 Post(s)
Liked 1,304 Times in 815 Posts
Yes, in principle it can be repaired, but unless there's great sentimental value in the bike, or you're willing and able to do the work yourself, it's likely not worthwhile.

There are four tubes that come together in the bottom bracket shell. The simplest fix, if it is only the shell that has failed and the tubes are intact, is to make several cuts in the shell, sweat off the pieces individually, fit a new shell and braze it in place. It's still a lot of work. If one or more of the tubes themselves have failed, then those would also have to be replaced. At that point, you're looking at the cost of a new custom frame.
JohnDThompson is offline  
Old 04-07-21, 05:16 PM
  #8  
Troul 
:D
 
Troul's Avatar
 
Join Date: Oct 2013
Location: Mich
Posts: 4,095
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked 966 Times in 703 Posts
To do it, I would at minimum: Remove the bottom bracket assembly, cabling, hardware within the area of the issue, grind down to bare metal the area with separating metal sections, have it tig welded together. Then, make a "pie" cut out of new tube material to wedge in the distressed area following up with it being tig welded in place. Prep the surfaces with primer, finish it off with paint, & apply a clear coat. Reassemble the parts.
__________________
-Oh Hey!
Troul is offline  
Likes For Troul:
Old 04-07-21, 05:41 PM
  #9  
veganbikes
Clark W. Griswold
 
Join Date: Mar 2014
Location: ,location, location
Posts: 8,658

Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), Cilo Road Frame, Proteus frame, Ti 26 MTB

Mentioned: 38 Post(s)
Tagged: 0 Thread(s)
Quoted: 2388 Post(s)
Liked 1,388 Times in 933 Posts
Originally Posted by Air View Post
Well...worth is subjective, right? I spent over a year dialing it in till it was perfect, where 80 mile rides didn't feel much longer than 30 and put thousands into it over the years. What's that time, sunk cost, comfort, and familiarity "worth"? A lot...to me! It was my fourth bike, and the only one I could get to feel like a body part while riding. I figure a new bike will require the same energy to get to hopefully about the same level. If there was an easy fix, it would be worth it.

But I agree with you, if the only solution was essentially disassembling the frame and machining a new BB only to worry where the next point of failure will crop up, it's better to start putting effort into something new.
If you enjoyed the bike measure everything or get help from a fitter and look into custom frame builders. As a Clyde you can have similar geometry tuned to you but with a stronger frame built for your height and weight which could last a lifetime. It seems you love the bike so give it a proper viking funeral and explain that passion to the person building your frame or talk to a few builders and shop around and see who fits your aesthetic best.
veganbikes is offline  
Likes For veganbikes:

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.