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

Cracked dura ace crank?

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.

Cracked dura ace crank?

Old 01-12-10, 09:12 PM
  #1  
mzeffex 
Senior Member
Thread Starter
 
mzeffex's Avatar
 
Join Date: Mar 2009
Location: Colorado
Posts: 9,458

Bikes: Something Canadian, something Italian, something American, and something German

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Likes: 0
Liked 14 Times in 8 Posts
Cracked dura ace crank?

I just picked this up used then realized this:

The green I think is supposed to be there, the red not so sure. Pictured is where the crank arm enters the spider. It is kind of raised, so is it just forging?

__________________
Originally Posted by rjones28 View Post
Are they talking about spectators feeding the cyclists? You know, like don't feed the bears?

Last edited by mzeffex; 01-12-10 at 09:57 PM.
mzeffex is offline  
Old 01-12-10, 10:01 PM
  #2  
MikeWinVA
Senior Member
 
Join Date: Oct 2009
Location: Northern/Central VA
Posts: 212

Bikes: Specialized Sirrus, Univega Activa ST Hybrid, 70's Schwinn Traveler, Giant Innova, Nishiki Mixte

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Get your money back if you can.

Assuming you have some $$$ tied up in this, if you can't get your money back and want to be sure, run it by a machine shop and have them do a penetrating dye test.
MikeWinVA is offline  
Old 01-12-10, 10:21 PM
  #3  
Schnayke
Senior Member
 
Join Date: Feb 2006
Location: Medford, OR
Posts: 325
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I had a stronglight that came apart right there, it was on my fixed and I almost hit a car. Good thing I still had a break, it just took me a second to remember it was there, and to stop wondering why I was coasting. Mine didn't fall apart though, it just spins like a free wheel now. lol
Schnayke is offline  
Old 01-13-10, 06:26 AM
  #4  
mzeffex 
Senior Member
Thread Starter
 
mzeffex's Avatar
 
Join Date: Mar 2009
Location: Colorado
Posts: 9,458

Bikes: Something Canadian, something Italian, something American, and something German

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Likes: 0
Liked 14 Times in 8 Posts
It's not cracked. It's part of the manufacturing process.
__________________
Originally Posted by rjones28 View Post
Are they talking about spectators feeding the cyclists? You know, like don't feed the bears?
mzeffex is offline  
Old 01-13-10, 07:49 AM
  #5  
FBinNY
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 35,964

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 125 Post(s)
Tagged: 1 Thread(s)
Quoted: 4372 Post(s)
Likes: 0
Liked 50 Times in 44 Posts
It looks more like flash then a crack. Flash is raised metal whereas a crack would not be. It's a normal result of the manufacturing process, resulting from a gap in the edge of the production tooling which allows excess metal to flow out a bit. Usually it's broken, polished or machined off later, but not always, especially in non-critical places or where they don't expect it to be visible in the finished assembly, like the back of a crank arm. Don't sweat it, enjoy your new cranks.
FBinNY is offline  
Old 01-13-10, 08:09 AM
  #6  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,294

Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 1839 Post(s)
Likes: 0
Liked 777 Times in 565 Posts
Originally Posted by mzeffex View Post
It's not cracked. It's part of the manufacturing process.
I don't agree, I think it's broken. I don't have a Dura Ace crank but I just inspected two 9-speed Ultegra cranks, two 8-speed 105's and a couple of old SR and Suguino cranks and NONE of these have any molding flash, forging marks or similar parting lines on either side of the spider/hub junction. The hub to spider transitions on all of these are completely smooth.

I can't believe a Dura Ace crank would be less finely finished than these are so I have to believe yours is cracked.

Don't use it.
HillRider is offline  
Old 01-13-10, 11:22 AM
  #7  
calamarichris
Horse Categorie
 
calamarichris's Avatar
 
Join Date: Sep 2007
Location: Carlsbad, CA
Posts: 6,205

Bikes: '09 Felt F55, '84 Masi Cran Criterium, (2)'86 Schwinn Pelotons, '86 Look Equippe Hinault, '09 Globe Live 3 (dogtaxi), '94 Greg Lemond, '99 GT Pulse Kinesis

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 235 Post(s)
Liked 66 Times in 40 Posts
Originally Posted by HillRider View Post
I don't agree, I think it's broken. I don't have a Dura Ace crank but I just inspected two 9-speed Ultegra cranks, two 8-speed 105's and a couple of old SR and Suguino cranks and NONE of these have any molding flash, forging marks or similar parting lines on either side of the spider/hub junction. The hub to spider transitions on all of these are completely smooth.

I can't believe a Dura Ace crank would be less finely finished than these are so I have to believe yours is cracked.

Don't use it.
I disagree completely. The new Dura Ace (Hollowtech) is made with a different process than those earlier, solid cranks you're comparing it to. The crank is fine. Mine had it when brand-new. Shimano puts it on the nearly-invisible underside of the crank. True, the underside is not as pretty as those earlier cranks, but overall it's much, much (& much-much) lighter and stiffer.
calamarichris is offline  
Old 01-13-10, 11:40 AM
  #8  
HillRider
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,294

Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!

Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 1839 Post(s)
Likes: 0
Liked 777 Times in 565 Posts
Originally Posted by calamarichris View Post
I disagree completely. The new Dura Ace (Hollowtech) is made with a different process than those earlier, solid cranks you're comparing it to. The crank is fine. Mine had it when brand-new. Shimano puts it on the nearly-invisible underside of the crank. True, the underside is not as pretty as those earlier cranks, but overall it's much, much (& much-much) lighter and stiffer.
OK, I missed that it was a Hollowtech II crank. I was, as you noted, comparing it to square taper and Octalink cranks and they look nothing like the one in the picture.
HillRider is offline  
Old 01-13-10, 04:35 PM
  #9  
kycycler
Senior Member
 
Join Date: Mar 2007
Location: Louisville, KY
Posts: 469

Bikes: Trek Madone 5.5, Klein Q Pro Elite, Surley LHT

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The green areas look like casting marks. The red area looks like a crack. Get a 10x magnifying glass and look at the area. If it is a crack you will not be able to see the bottom of the area. Flashing or casting marks will be very obvious.
kycycler is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
WizardOfBoz
Bicycle Mechanics
5
04-05-17 04:41 PM
shot
Singlespeed & Fixed Gear
14
11-23-15 02:19 PM
mststationary
Bicycle Mechanics
0
07-22-11 02:37 PM
tjbmarks
Bicycle Mechanics
16
02-19-11 10:11 AM
Nachoman
Road Cycling
15
04-13-10 12:22 PM

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.