Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Repair options for a cracked rear dropout

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Repair options for a cracked rear dropout

Old 05-24-17, 01:18 PM
  #1  
Spaghetti Legs 
Senior Member
Thread Starter
 
Join Date: Dec 2014
Location: Central Virginia
Posts: 4,969

Bikes: Numerous

Mentioned: 136 Post(s)
Tagged: 0 Thread(s)
Quoted: 1629 Post(s)
Liked 2,741 Times in 842 Posts
Repair options for a cracked rear dropout

I'm curious what you folks think could be done with this. Replace entire dropout? Repair? Hang on wall and admire?

Only pic I have, wondering if it's worth going after.
Attached Images
File Type: jpg
CinelliSuperCorsa54.jpg (96.8 KB, 286 views)
__________________
N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '82 Colnago Super, '95 Gios Compact Pro, '95 Carrera Zeus, '84 Basso Gap, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, '84 Paletti Super Prestige, Heron Randonneur

Spaghetti Legs is offline  
Old 05-24-17, 02:06 PM
  #2  
Chombi1 
Senior Member
 
Chombi1's Avatar
 
Join Date: Nov 2015
Posts: 4,248
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 1528 Post(s)
Likes: 0
Liked 680 Times in 448 Posts
Maybe dropout replacement by a good frame builder would be most cost effective and safer
Not sure how much damage the removal and rebrazing heat might do to the chrome on the stays though....m
Chombi1 is online now  
Old 05-24-17, 02:15 PM
  #3  
rhm
multimodal commuter
 
rhm's Avatar
 
Join Date: Nov 2006
Location: NJ, NYC, LI
Posts: 19,847

Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...

Mentioned: 572 Post(s)
Tagged: 0 Thread(s)
Quoted: 1903 Post(s)
Liked 548 Times in 326 Posts
I have a hunch a good welder might be able to fix that. That is, weld the dropout while keeping the rest of the frame cold, so cold that the chrome isn't hurt. You'll have to do a lot of filing, then paint...
rhm is offline  
Old 05-24-17, 02:20 PM
  #4  
gugie 
Bike Butcher of Portland
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 11,410

Bikes: It's complicated.

Mentioned: 1273 Post(s)
Tagged: 0 Thread(s)
Quoted: 4542 Post(s)
Liked 5,311 Times in 2,129 Posts
Just about anything's repairable. I'm wondering why a vertical dropout needs an adjustment screw? I would think you could just fill it will brass and do a little filing. A whole lotta flux on the chrome wold probably save it - some "paint to match" masking the chrome and dropout faces, and it might be as good as new, 'cept the screw hole would be filled.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 05-24-17, 02:22 PM
  #5  
GordoTrek
Senior Member
 
GordoTrek's Avatar
 
Join Date: Nov 2011
Location: Rochester, NY
Posts: 1,342

Bikes: 1962 Carlton Franco-Suisse Custom,1968 Raleigh DL-1/Tourist, 1971 Holdsworth Professional, 1973 Holdsworth Mistral,1973 Raleigh Gran Sport,1974 Raleigh Grand Prix, 1993 Trek 2200 Composite, 2011 Trek 7.3FX

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 67 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
had the same issue on my holdsworth but i was going to repaint the frame anyway. My holdsworth was not nearly as nice as yours but i wanted to save it. I believe yours is worth saving.
GordoTrek is offline  
Old 05-24-17, 02:33 PM
  #6  
79pmooney
Senior Member
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,203

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 121 Post(s)
Tagged: 0 Thread(s)
Quoted: 4348 Post(s)
Liked 3,411 Times in 2,209 Posts
Another approach. Not as elegant but would not require heat. Sister on another piece of steel from the outside, cut to the dropout side profile and machined for the axle nut flats and adjusting screw rise. Three machine screws to hold it in place, one each beyond each stay and one into the hanger. Paint it the same red, use a longer rear wheel axle and QR and ride. One outfit that could certainly do this would be TiCycles. It wouldn't be cheap. (Beware, if you go this approach, they may suggest something better! They're pretty sharp.)

Ben
79pmooney is offline  
Old 05-24-17, 02:33 PM
  #7  
randyjawa 
Senior Member
 
randyjawa's Avatar
 
Join Date: Apr 2007
Location: Thunder Bay, Ontario, Canada - burrrrr!
Posts: 11,553

Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma

Mentioned: 209 Post(s)
Tagged: 0 Thread(s)
Quoted: 1327 Post(s)
Likes: 0
Liked 1,583 Times in 875 Posts
Take it to a professional welder and have him attempt a repair(weld, don't braze). You will loose the chrome on the drop and need to repaint it, but that is a small price to pay. I would also not go with the adjustment hole, weld it solid.

Needless to say, the repair will diminish the value of the frame but at least you will have it on the road. Will it break? Who knows but my bet would be that it will be as strong or stronger than it was, with the threaded hole.

If all that does not work, replace the drop and paint it up
__________________
"98% of the bikes I buy are projects".
randyjawa is offline  
Old 05-24-17, 03:12 PM
  #8  
Chombi1 
Senior Member
 
Chombi1's Avatar
 
Join Date: Nov 2015
Posts: 4,248
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 1528 Post(s)
Likes: 0
Liked 680 Times in 448 Posts
Vertical dropout adjuster......did not really make sense, I gues, unless the builder was using jigs that were not aligned properly......
Chombi1 is online now  
Old 05-24-17, 03:20 PM
  #9  
Chombi1 
Senior Member
 
Chombi1's Avatar
 
Join Date: Nov 2015
Posts: 4,248
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 1528 Post(s)
Likes: 0
Liked 680 Times in 448 Posts
This frameset being a Cinelli, sure makes it worth fixing to "as original" condition.
I sure would not was what looks like a bodged up repair on it if it were mine.....
Unfortunately it's the chromed stays that will make the job difficult. Would have been a slam dunk to braze on a new dropout (can builders still find those dropouts?) If the stays were painted, as repaint of the stays would be so easy.
Chombi1 is online now  
Old 05-24-17, 03:27 PM
  #10  
xiaoman1 
Senior Member
 
xiaoman1's Avatar
 
Join Date: Mar 2014
Location: City of Angels
Posts: 5,084

Bikes: A few too many

Mentioned: 42 Post(s)
Tagged: 1 Thread(s)
Quoted: 1332 Post(s)
Liked 2,049 Times in 1,123 Posts
+1 on welding...Chamfer both pieces on all sides so you have V (valley) for a good strong weld. You can then later file the excess from the drop and still have enough strength in the weld that it will not cause any additional worry.
Bring it to a pro to do the welding. Use a heat sink at the tubes to minimize heat to chrome and paint and you will be good to go....no gas (Oxy-ace) welding, let electricity and wire be your friend. Easy and quick job.
Ben
__________________
"EVERY PERSON IS GUILTY OF ALL THE GOOD THEY DID NOT DO"
Voltaire

Voice recognition may sometimes create odd spelling and grammatical errors



xiaoman1 is offline  
Old 05-24-17, 03:29 PM
  #11  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,560

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 98 Post(s)
Tagged: 0 Thread(s)
Quoted: 3850 Post(s)
Liked 2,507 Times in 1,545 Posts
Are they semi-vertical dropouts?
__________________
Originally Posted by chandltp
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 05-24-17, 03:34 PM
  #12  
repechage
Senior Member
 
Join Date: Jun 2006
Posts: 19,200
Mentioned: 125 Post(s)
Tagged: 0 Thread(s)
Quoted: 3031 Post(s)
Liked 2,206 Times in 1,591 Posts
I have a welder I could trust, I'm more of a TIG solution for this one, remove paint within 3/8", talk to the welder, ditch the adjuster for this side, might require a tight V to obtain a clean surface, weld, and file back as needed.

Caswell plating after and touch up paint.

The TIG will add heat fast and of short duration.

otherwise, a stainless washer (maybe machined to fit) could be silver soldiered to the outside and cut back, extra material of some benefit to add strength.
repechage is offline  
Old 05-24-17, 03:43 PM
  #13  
sdn40
Senior Member
 
Join Date: Sep 2016
Location: Green Bay, WI
Posts: 645

Bikes: 88 Cannondale Criterium

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 291 Post(s)
Liked 145 Times in 91 Posts
Has anyone tried JB Weld in a situation like this ?
I know its a longshot - just tossing it out there as a clean no heat possiblility - especially if you filled the threads
The threads would provide teeth and gotta believe that would provide enough strength since the surrounding area still provides support as well ?

Last edited by sdn40; 05-24-17 at 03:46 PM.
sdn40 is offline  
Old 05-24-17, 03:50 PM
  #14  
nashvillebill
Senior Member
 
Join Date: Mar 2016
Location: Phoenix AZ
Posts: 376
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Likes: 0
Liked 3 Times in 2 Posts
Originally Posted by repechage
I have a welder I could trust, I'm more of a TIG solution for this one, remove paint within 3/8", talk to the welder, ditch the adjuster for this side, might require a tight V to obtain a clean surface, weld, and file back as needed....
The TIG will add heat fast and of short duration....
I concur 100%. TIG from a good welder, a small tight V so penetration could be achieved without resorting to brute-force massive amounts of heat for a long duration.

I believe it may be possible to avoid ruining the chrome as well. The key would be to fab some good aluminum or steel heat sinks that could be clamped tightly at the chromed area. That lets the heat from the welding escape outward rather than remaining localized. (Wet rags is not a good idea to keep the chrome cool IMO). Chrome itself can resist a fair amount of heat, think of guns that have chrome plated internal parts, or chrome piston rings.

The main thing though is to weld quick and fast, while doing a good job of course. Like soldering transistors: get in, get out fast.

Now if this required keeping the adjusting screws, then all bets are off, I would not trust a repair then.
nashvillebill is offline  
Old 05-24-17, 03:51 PM
  #15  
nashvillebill
Senior Member
 
Join Date: Mar 2016
Location: Phoenix AZ
Posts: 376
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Likes: 0
Liked 3 Times in 2 Posts
Originally Posted by sdn40
Has anyone tried JB Weld in a situation like this ?
I know its a longshot - just tossing it out there as a clean no heat possiblility - especially if you filled the threads
The threads would provide teeth and gotta believe that would provide enough strength since the surrounding area still provides support as well ?
Not a chance in the world for JB Weld to work here. This is stressed in tension and the tensile strength/adhesion of JB Weld is nowhere near as good as the original steel.
nashvillebill is offline  
Old 05-24-17, 03:54 PM
  #16  
sdn40
Senior Member
 
Join Date: Sep 2016
Location: Green Bay, WI
Posts: 645

Bikes: 88 Cannondale Criterium

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 291 Post(s)
Liked 145 Times in 91 Posts
Originally Posted by nashvillebill
Not a chance in the world for JB Weld to work here. This is stressed in tension and the tensile strength/adhesion of JB Weld is nowhere near as good as the original steel.
I definitely would defer to someone that was sure it wouldn't work.
It is never my first choice but figured this particular situation was worth a mention since you could fill the threads
sdn40 is offline  
Old 05-24-17, 04:05 PM
  #17  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,577

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3409 Post(s)
Liked 3,013 Times in 1,730 Posts
Originally Posted by ThermionicScott
Are they semi-vertical dropouts?
They look like Gipiemme 1800AX:

JohnDThompson is offline  
Old 05-24-17, 04:12 PM
  #18  
Chombi1 
Senior Member
 
Chombi1's Avatar
 
Join Date: Nov 2015
Posts: 4,248
Mentioned: 101 Post(s)
Tagged: 0 Thread(s)
Quoted: 1528 Post(s)
Likes: 0
Liked 680 Times in 448 Posts
Originally Posted by JohnDThompson
They look like Gipiemme 1800AX:

Not exactly the same. The ones on the bike, seems to have round flanges cast on to the dropout ends that go into the stay tubes......
Didn't Trek use similar rear dropouts on their bikes?
Chombi1 is online now  
Old 05-24-17, 04:16 PM
  #19  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,570
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 17844 Post(s)
Liked 4,278 Times in 3,191 Posts
Is that a current production $2000+ frame?

There may be benefits of doing the job right. Contact Cinelli to see if you can acquire the dropout, then get it brazed in. Then chromed as needed. The paintwork pattern would lend itself to being touched up and would be invisible.

Last edited by CliffordK; 05-24-17 at 04:19 PM.
CliffordK is offline  
Old 05-24-17, 04:29 PM
  #20  
gugie 
Bike Butcher of Portland
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 11,410

Bikes: It's complicated.

Mentioned: 1273 Post(s)
Tagged: 0 Thread(s)
Quoted: 4542 Post(s)
Liked 5,311 Times in 2,129 Posts
Originally Posted by JohnDThompson
They look like Gipiemme 1800AX:

John, I was going to post and ask you, what's your opinion on TIG'ing vs filling the adjuster hole with brass, or even silver, and getting it to flow through the crack via capillary action, then file and sand?

I'm pretty convinced it could be done without ruining the chrome up on the stays, and since the dropouts are painted, that could be easily touched up.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 05-24-17, 04:32 PM
  #21  
gugie 
Bike Butcher of Portland
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 11,410

Bikes: It's complicated.

Mentioned: 1273 Post(s)
Tagged: 0 Thread(s)
Quoted: 4542 Post(s)
Liked 5,311 Times in 2,129 Posts
Originally Posted by Spaghetti Legs
I'm curious what you folks think could be done with this. Replace entire dropout? Repair? Hang on wall and admire?

Only pic I have, wondering if it's worth going after.
Couldn't find it on eBay, but it's clearly a Cinelli Supercorsa, well worth saving. Local seller?
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 05-24-17, 04:46 PM
  #22  
nashvillebill
Senior Member
 
Join Date: Mar 2016
Location: Phoenix AZ
Posts: 376
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Likes: 0
Liked 3 Times in 2 Posts
Originally Posted by nashvillebill
Not a chance in the world for JB Weld to work here. This is stressed in tension and the tensile strength/adhesion of JB Weld is nowhere near as good as the original steel.
To follow up and give some real numbers here: the original steel forging, if it's a decent quality, should have a tensile strength well over 30,000 psi. Bear in mind that it failed.

JB Weld has an advertised tensile strength of 3960 psi. That's roughly 1/10 of the original steel--and that's under perfect conditions (optimum epoxy mixture, good surface prep, etc)

A TIG rod or MIG wire will be E70 or higher. That means it will have a tensile stress of 70,000 psi--much higher than the original steel. A properly executed weld is stronger than the original steel (granted, the weld must be executed properly, which is not always easy). Shucks, even if someone were to use a "tombstone" buzz-box arc welder with a 6011 "farmer's rod", that weld will be 60,000 psi which will still be stronger than any mild steel out there.
nashvillebill is offline  
Old 05-24-17, 05:06 PM
  #23  
Andy_K 
Senior Member
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 14,600

Bikes: Yes

Mentioned: 507 Post(s)
Tagged: 0 Thread(s)
Quoted: 3104 Post(s)
Liked 3,444 Times in 1,315 Posts
Originally Posted by nashvillebill
Not a chance in the world for JB Weld to work here. This is stressed in tension and the tensile strength/adhesion of JB Weld is nowhere near as good as the original steel.
Is it? I was trying to visualize the forces on the frame here. When you're pedaling, the axle would be pulled against the top of the dropout, which isn't compromised. The crack looks to me like it would have been caused by the derailleur being pulled inward, which is a risk going forward but wouldn't happen under normal operation. The quick release should push equally on both sides of the crack, but I suppose under heavy pedaling the flex in the frame could produce a lot of twisting force here, and maybe that (and not my first guess about the derailleur hanger) caused the failure. Then again, it seems to me like the flex from pedaling should be in the opposite direction, compressing the cracked area rather than pulling it apart.

Am I missing something? I'll admit a fair amount of ignorance, and I'm pursuing the question mostly for my own education. I actually would have thought it's possible to ride this as is.
__________________
My Bikes
Andy_K is offline  
Old 05-24-17, 05:20 PM
  #24  
nashvillebill
Senior Member
 
Join Date: Mar 2016
Location: Phoenix AZ
Posts: 376
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Likes: 0
Liked 3 Times in 2 Posts
I wrote that it was in tension, but of course it's not in tension 100% of the time--the "tension" represents the worst-case scenario which is what it must be designed for. In certain conditions, the reaction from the axle will indeed be pushing towards the front of the dropout or perhaps to the top/front (let's say the 1 o'clock position if the top of the drop was 12:00) . However, the worst-case scenario might be when the frame is flexed, perhaps leaning in a corner, or braking, and in those cases the axle is wanting to "open" the dropout slot. Perhaps hitting a pothole, then the axle is driving upwards into the rounded upper part of the dropout slot. That is also trying to "open" the dropout and thus putting the cracked area in tension. Or hitting a pothole while leaning and braking! A hundred pounds of force, twisting the other end of the axle, can act like a lever and try to force that slot open with tremendous force.
nashvillebill is offline  
Old 05-24-17, 05:21 PM
  #25  
sdn40
Senior Member
 
Join Date: Sep 2016
Location: Green Bay, WI
Posts: 645

Bikes: 88 Cannondale Criterium

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 291 Post(s)
Liked 145 Times in 91 Posts
Originally Posted by Andy_K
Is it? I was trying to visualize the forces on the frame here. When you're pedaling, the axle would be pulled against the top of the dropout, which isn't compromised. The crack looks to me like it would have been caused by the derailleur being pulled inward, which is a risk going forward but wouldn't happen under normal operation. The quick release should push equally on both sides of the crack, but I suppose under heavy pedaling the flex in the frame could produce a lot of twisting force here, and maybe that (and not my first guess about the derailleur hanger) caused the failure. Then again, it seems to me like the flex from pedaling should be in the opposite direction, compressing the cracked area rather than pulling it apart.

Am I missing something? I'll admit a fair amount of ignorance, and I'm pursuing the question mostly for my own education. I actually would have thought it's possible to ride this as is.
I was hesitant to post my outside the box idea because while my thoughts were along the same lines as yours, shared forces and back pressure relief due to filled threads, there may be other forces that more knowledgeable people can speak of. Since the next step may be a snapped dropout leading to a crash, I'll gladly defer to err on the side of caution.
sdn40 is offline  

Thread Tools
Search this Thread

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

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.