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

infamous campy SR crank spider web hairline crack: real question

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.

infamous campy SR crank spider web hairline crack: real question

Old 07-27-20, 07:51 PM
  #1  
orangeology 
category ii hoarder
Thread Starter
 
orangeology's Avatar
 
Join Date: Aug 2011
Location: NYC+NNJ
Posts: 1,274

Bikes: i don't have a bike. a few frames, forks and some parts. that's all

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked 40 Times in 25 Posts
infamous campy SR crank spider web hairline crack: real question

yes. that. the notorious crack, more like hairline prediction of a crack in the back of the spider junction. i've read/searched tons of articles/posts inc. the ones on C&V here yet with some real curiosity.

will it really break under 'ordinary' riding? non-criterium, non-compete, less than a few miles daily city riding, i mean. i've read horrors breaking at pedal eyes, but didn't really see the cases spider arm really "broken"? i understand no one can guarantee it, just asking 'in general', common sense. should a less-than-a-millimeter hairline be really a panicking thing or like hey, it's common just ride with a caution?

i do have round files, am capable of filing/sanding things, and it doesn't seem to be too hard to file a couple mils away. should i just do it and forget about it?

got one pair that had looked totally fine in the pics, then i see it in person. less than a millimeter, obvious initiation that i can also see from the outside flat too. (and trust me, not the first time i see this). yes i'd easily return 'em unless it's from South Africa—and the one i had to wait nearly two months to arrive... under current situation, it'll most likely take another two months to sort it out—return, refund etc etc.

i mean, the problem is always, that SR/NR crank arms are too pretty to give up...

orangeology is offline  
Old 07-27-20, 07:54 PM
  #2  
P!N20
Senior Member
 
P!N20's Avatar
 
Join Date: Aug 2010
Posts: 1,086
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 501 Post(s)
Liked 405 Times in 262 Posts
Originally Posted by orangeology View Post
will it really break under 'ordinary' riding?
Yes, they can. Get the file out.
P!N20 is offline  
Likes For P!N20:
Old 07-27-20, 09:21 PM
  #3  
Chombi1 
Senior Member
 
Chombi1's Avatar
 
Join Date: Nov 2015
Posts: 3,199
Mentioned: 94 Post(s)
Tagged: 0 Thread(s)
Quoted: 1139 Post(s)
Likes: 0
Liked 151 Times in 117 Posts
What's scary about those cracks is it can literally be just the tip 9f the iceberg, where there's actually a lot more damage within the crank, under the surface, not visible from the outside......pretty much a potential "silent killer".
Easing it out with a file can give you an idea on how deep it really goes into the crank.
Chombi1 is offline  
Likes For Chombi1:
Old 07-27-20, 09:43 PM
  #4  
HTupolev
Senior Member
 
Join Date: Apr 2015
Location: Seattle
Posts: 3,440
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1545 Post(s)
Liked 505 Times in 263 Posts
Originally Posted by orangeology View Post
will it really break under 'ordinary' riding?
Yes, easily. That crack is a serious stress riser. Even at fairly modest pedal forces, it'll gradually propagate itself and eventually break.
HTupolev is offline  
Likes For HTupolev:
Old 07-27-20, 09:46 PM
  #5  
Salamandrine 
Senior Member
 
Join Date: Oct 2015
Location: Los Angeles
Posts: 6,192

Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr

Mentioned: 118 Post(s)
Tagged: 0 Thread(s)
Quoted: 2267 Post(s)
Liked 499 Times in 362 Posts
FWIW I rode a campy crank with a small starter crack like that in the web for years, before I finally chickened out and replaced it. I think I've seen a picture once of someone who let it go until it actually failed. That would take a while. Keep a careful eye on it and if it starts to get substantially bigger, stop riding it. I'm not sure if filing the web now that a crack has started will be any help.

This isn't like cracks that begin at the pedal eye or across the main body of the crank arm. Those fail relatively quickly and often dangerously, and any crank with that type of crack should be retired immediately. I broke a crank completely through without warning once, at it was both disconcerting and potentially dangerous. From then on I learned my lesson and watched carefully for cracks.
Salamandrine is offline  
Likes For Salamandrine:
Old 07-27-20, 10:40 PM
  #6  
orangeology 
category ii hoarder
Thread Starter
 
orangeology's Avatar
 
Join Date: Aug 2011
Location: NYC+NNJ
Posts: 1,274

Bikes: i don't have a bike. a few frames, forks and some parts. that's all

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked 40 Times in 25 Posts
done. luckily the surface was all, no internal fatigue/cracks. did moderate filing & polishing on both sides. i can sleep now.

orangeology is offline  
Likes For orangeology:
Old 07-27-20, 10:46 PM
  #7  
Drillium Dude 
NNNN
 
Drillium Dude's Avatar
 
Join Date: Jul 2009
Location: Bothell, WA
Posts: 10,320

Bikes: 1973 Colnago Super, 1973 Colnago Super concept, 1979 Medici Pro Strada, 1979 Dennis Sparrow, 1980 Alpina, 1981 Bianchi Super Leggera, 1983 Colnago Mexico, 1985 Casati Perfection, 1985 Somec Super Corsa, 2002 Bill Davidson custom

Mentioned: 189 Post(s)
Tagged: 0 Thread(s)
Quoted: 1568 Post(s)
Liked 889 Times in 448 Posts
That's a nice, clean job of it

DD
__________________
My Flickr pics: https://www.flickr.com/photos/30331021@N08/

Drillium Dude is offline  
Likes For Drillium Dude:
Old 07-27-20, 10:49 PM
  #8  
orangeology 
category ii hoarder
Thread Starter
 
orangeology's Avatar
 
Join Date: Aug 2011
Location: NYC+NNJ
Posts: 1,274

Bikes: i don't have a bike. a few frames, forks and some parts. that's all

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked 40 Times in 25 Posts
Originally Posted by Drillium Dude View Post
That's a nice, clean job of it
DD
thank you. means a lot, especially from you, sir!
orangeology is offline  
Likes For orangeology:
Old 07-28-20, 12:41 AM
  #9  
mech986 
Senior Member
 
mech986's Avatar
 
Join Date: Sep 2010
Location: La Habra, California
Posts: 588

Bikes: Italvega Super Speciales and Superlights

Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 275 Post(s)
Liked 70 Times in 52 Posts
Funny how threads about the same topic sometimes pop up at the same time:

https://groups.google.com/forum/#!to...es/b3DsZL4XQiU

and a link from Jim Merz's reply:
https://forum.cyclinguk.org/viewtopic.php?f=5&t=121671




Note how the crack starts on the high side of the crank downstroke where all the force would be down and out due to the pedal and crank arm acting as a lever. Also, in this picture, does it look a little like the web was filed a bit?




Pretty sobering!
__________________
Italvega and Torpado Enthusiast

Last edited by mech986; 07-28-20 at 12:46 AM.
mech986 is offline  
Likes For mech986:
Old 07-28-20, 06:28 AM
  #10  
Moe Zhoost
Half way there
 
Moe Zhoost's Avatar
 
Join Date: Sep 2015
Location: Durham, NC
Posts: 2,166

Bikes: Many, and the list changes frequently

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 678 Post(s)
Liked 416 Times in 252 Posts
It looks like you've resolved your issue; however double check for micro-cracks by stressing the crank while examining under bright light and magnification.

I was rudely introduced to the road a few years back when I broke a crank so I routinely check my vintage cranks using this method. If there are cracks, you'll see them.
Moe Zhoost is offline  
Likes For Moe Zhoost:
Old 07-28-20, 06:53 AM
  #11  
Salamandrine 
Senior Member
 
Join Date: Oct 2015
Location: Los Angeles
Posts: 6,192

Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr

Mentioned: 118 Post(s)
Tagged: 0 Thread(s)
Quoted: 2267 Post(s)
Liked 499 Times in 362 Posts
Note that the beach marks show that the crack had extended approximately 40% of the way across the crank shaft, and yet someone continued to ride it. It would have been easily visible, yet it was ignored. +1 Inspect cranks regularly with light and magnification.Not unusual for used campy record cranks from BITD to have really big miles on them.
Salamandrine is offline  
Likes For Salamandrine:
Old 07-28-20, 07:00 AM
  #12  
hazetguy 
Custom User Title
 
hazetguy's Avatar
 
Join Date: Nov 2004
Location: asheville
Posts: 1,429

Bikes: are filling up my basement.

Mentioned: 93 Post(s)
Tagged: 0 Thread(s)
Quoted: 999 Post(s)
Likes: 0
Liked 547 Times in 329 Posts
Originally Posted by mech986 View Post
Funny how threads about the same topic sometimes pop up at the same time:
Ha, yeah. I was going to post the coincidence, since I am the one that started the CR thread. (i think you have to be a logged in member to read the CR list).
I received a ton of replies to that thread, both on CR and via private message. some say to file out the crack (overwhelming opinion), with a few saying the danger still lurks within.
hazetguy is offline  
Old 07-28-20, 07:49 AM
  #13  
Murray Missile 
Bike hoarder.
 
Murray Missile's Avatar
 
Join Date: Jun 2013
Location: 700 Ft. above sea level.
Posts: 2,235

Bikes: Just as many as there were awhile ago.

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 296 Post(s)
Liked 241 Times in 142 Posts
2 hours before this posted I bought a really clean Super Record crankset off Ebay. After reading this I went back and took a REALLY close look at the pictures and there appears to be a small crack. 😮😕 Has anyone tried drilling a hole at the end of the crack then grinding it out to a V shape and TIG welding it? I have done this with great success on other aluminum items. It would only take a "tack" weld to fill the V so the heat affected zone would be quite small. I would leave the TIG weld to a friend, he has a custom metal fabrication shop and does this type of repair on auto and motorcycle components often. He's a much better welder than me.

Here's a picture from the auction, it's not the best. The area in question is circled in red, I can't tell if it's just a line, a crack or dirt. I guess I'll know for sure when it gets here.


Last edited by Murray Missile; 07-28-20 at 04:43 PM. Reason: Photo added.
Murray Missile is offline  
Old 07-28-20, 04:49 PM
  #14  
orangeology 
category ii hoarder
Thread Starter
 
orangeology's Avatar
 
Join Date: Aug 2011
Location: NYC+NNJ
Posts: 1,274

Bikes: i don't have a bike. a few frames, forks and some parts. that's all

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked 40 Times in 25 Posts
double checked it with a loupe under a blinding light. currently no more visible crack or sign. and will check often to see if there's any.
excited to see if the filing really has done any 'practical' effect.

for whom might have wondered, i've used:
1. gentle hand-filing with a hobby size round file, about 1/16
2. finishing with 3M320F block. peel-off-cut a small piece like a blanket, taped to a small rod. applied with the hand drill with low-speed. very meditating it was.


wanted to do it delicate way, have seen horrendous jobs on the web, that actually ruined the nice connecting outline from the arm the the spider.
happy with the output, for now.

thanks for all the insights & advice.
orangeology is offline  
Likes For orangeology:
Old 07-28-20, 05:23 PM
  #15  
norskagent
car dodger
 
norskagent's Avatar
 
Join Date: Aug 2005
Location: garner/raleigh nc
Posts: 3,410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 38 Times in 23 Posts
Would like to see more pics of filed / fixed cranks...
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
norskagent is offline  
Likes For norskagent:
Old 07-28-20, 05:33 PM
  #16  
P!N20
Senior Member
 
P!N20's Avatar
 
Join Date: Aug 2010
Posts: 1,086
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 501 Post(s)
Liked 405 Times in 262 Posts
Originally Posted by Moe Zhoost View Post
I was rudely introduced to the road a few years back when I broke a crank so I routinely check my vintage cranks using this method.
It's not just vintage cranks. I've broken two 'modern' (2010-ish) drive side cranks. The first was an FSA Gossamer that I could feel had some lateral movement, sure enough, a crack had developed on the crank arm. The second was a Sugino RD2 that broke clean off while riding, luckily I managed to keep it upright.

P!N20 is offline  
Likes For P!N20:
Old 07-28-20, 05:45 PM
  #17  
orangeology 
category ii hoarder
Thread Starter
 
orangeology's Avatar
 
Join Date: Aug 2011
Location: NYC+NNJ
Posts: 1,274

Bikes: i don't have a bike. a few frames, forks and some parts. that's all

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Liked 40 Times in 25 Posts
Originally Posted by norskagent View Post
Would like to see more pics of filed / fixed cranks...
here you have them. quick iphone shots with desk light.





orangeology is offline  
Likes For orangeology:
Old 07-28-20, 06:02 PM
  #18  
norskagent
car dodger
 
norskagent's Avatar
 
Join Date: Aug 2005
Location: garner/raleigh nc
Posts: 3,410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 38 Times in 23 Posts
Nice to see how far up the arm you went, helpful!
Will try to post pics of mine tomorrow.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
norskagent is offline  
Old 07-28-20, 06:24 PM
  #19  
noobinsf 
Senior Member
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 2,000

Bikes: CURRENT: '82 Univega Competizione, '72 Motobecane Grand Record, '74 Campania Professional, '83 Mercian KOM Touring, '91 Univega Alpina Comp PAST: '72 Puch Bergmeister, '72ish Peugeot UO-8, '86 Univega Gran Premio, '85 Univega Viva Touring

Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 609 Post(s)
Liked 334 Times in 232 Posts
Yep, I had a bounty last year with a beautiful frame and components, including an SR Royal super light crank. Sure enough, there was a hairline, and when I started filing, I couldn't find the end of the crack. Though I may re-purpose the chainrings at some point, the drive side crank is wall art.
noobinsf is offline  
Old 07-29-20, 06:16 AM
  #20  
mech986 
Senior Member
 
mech986's Avatar
 
Join Date: Sep 2010
Location: La Habra, California
Posts: 588

Bikes: Italvega Super Speciales and Superlights

Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 275 Post(s)
Liked 70 Times in 52 Posts
Originally Posted by Salamandrine View Post
Note that the beach marks show that the crack had extended approximately 40% of the way across the crank shaft, and yet someone continued to ride it. It would have been easily visible, yet it was ignored. +1 Inspect cranks regularly with light and magnification.Not unusual for used campy record cranks from BITD to have really big miles on them.
The cranks in my photos were part of a University Engineering school's materials study to see failure modes in bicycle components - once identified, the parts were continually stressed until failure. Not my pics nor my university but very practical in scope.
__________________
Italvega and Torpado Enthusiast
mech986 is offline  
Likes For mech986:
Old 07-29-20, 09:53 AM
  #21  
Salamandrine 
Senior Member
 
Join Date: Oct 2015
Location: Los Angeles
Posts: 6,192

Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr

Mentioned: 118 Post(s)
Tagged: 0 Thread(s)
Quoted: 2267 Post(s)
Liked 499 Times in 362 Posts
Originally Posted by mech986 View Post
The cranks in my photos were part of a University Engineering school's materials study to see failure modes in bicycle components - once identified, the parts were continually stressed until failure. Not my pics nor my university but very practical in scope.
Oh, thanks for that info. That makes more sense. I had never seen a campy crank with one of those spider starter cracks that had completely failed in real life.
Salamandrine is offline  
Old 07-29-20, 10:02 AM
  #22  
norskagent
car dodger
 
norskagent's Avatar
 
Join Date: Aug 2005
Location: garner/raleigh nc
Posts: 3,410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 38 Times in 23 Posts
Here's a campy triple currently on my Mclean, that I filed a year or so ago.


__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
norskagent is offline  
Likes For norskagent:
Old 07-29-20, 10:05 AM
  #23  
norskagent
car dodger
 
norskagent's Avatar
 
Join Date: Aug 2005
Location: garner/raleigh nc
Posts: 3,410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 38 Times in 23 Posts
and here is a pista crank on my raleigh track that I filed a few years ago. It has held up fine but I don't ride the bike that much.

__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
norskagent is offline  
Likes For norskagent:
Old 07-29-20, 08:06 PM
  #24  
qcpmsame 
Semper Fi
 
qcpmsame's Avatar
 
Join Date: Jan 2008
Location: Barrineau Park, Florida
Posts: 12,749

Bikes: 1980 Medici Pro Strada, 1984 Tommasini Prestige, 2012 Cannondale CAAD 10 Ultegra

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 1115 Post(s)
Liked 157 Times in 127 Posts
Nice job of polishing out the hairline orangeology . I worked in failure analysis of steel, in the construction industry (quality engineer,) for 30+ years, you might want to do a "poor man's" Magnaflux test to the spider, for peace of mind. Soak the spider liberally with WD-40, or even some thin spray lubricant, then wipe it dry after letting it sit for a bit. Once cleaned off, apply some baby powder to the entire piece, then blow it clean. If there is a crack anywhere you'll see it where the soaked in liquid has absorbed the powder.

Bill
__________________
Semper Fi, USMC, 1975-1977

I Can Do All Things Through Him, Who Gives Me Strength. Philippians 4:13


qcpmsame is offline  
Likes For qcpmsame:
Old 07-29-20, 08:16 PM
  #25  
BFisher 
Senior Member
 
BFisher's Avatar
 
Join Date: Aug 2013
Location: NEPA
Posts: 1,186

Bikes: '61 Schwinn Klunker, '68 Hercules Klapprad, '73 Raleigh Super Course, '79 Motobecane Grand Sprint, '82 Colnago Super, '87 Ironman Expert, '89 Puch Mistral Leader

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 343 Post(s)
Liked 537 Times in 309 Posts
Originally Posted by qcpmsame View Post
Nice job of polishing out the hairline orangeology . I worked in failure analysis of steel, in the construction industry (quality engineer,) for 30+ years, you might want to do a "poor man's" Magnaflux test to the spider, for peace of mind. Soak the spider liberally with WD-40, or even some thin spray lubricant, then wipe it dry after letting it sit for a bit. Once cleaned off, apply some baby powder to the entire piece, then blow it clean. If there is a crack anywhere you'll see it where the soaked in liquid has absorbed the powder.

Bill
I appreciate this tip. Thank you for sharing.
BFisher is offline  

Thread Tools
Search this Thread

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

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.