Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-17-12, 10:33 PM   #1
Chaotik
Newbie
Thread Starter
 
Join Date: Jun 2012
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Cosmetic or structural crack in aluminum fork

Hello,

I just purchased a old (early 90s) Cannondale Criterium 3.0 road bike from a friend. I'm a newbie at this.
I was riding it tonight but when I got home, I noticed a small crack on the fork. The fork is all alu, no carbon.
I've only had the bike a few days so I didn't notice is it's been there for a while or not.

I am wondering if the crack is only cosmetic or not. Most of the info I find online relates to carbon forks and the cracks I see are perpendicular to the fork whereas my crack is vertical (along the fork) and not exactly straight. It turns a bit.

Attached is a picture I took of the crack.

Any insight would be greatly appreciated.

Thanks !

Attached Images
File Type: jpg IMG_0115.jpg (90.3 KB, 121 views)
Chaotik is offline   Reply With Quote
Old 06-17-12, 10:58 PM   #2
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
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
Posts: 29,437
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 100 Post(s)
There's no way to tell from a picture. But from the shape of the scratch, it looks more like a scratch than a structural crack. I'd continue riding it, but keep a close eye on it if I suspected it was a crack. Mark the ends, or touch it up exactly up to the end, and see if it grows. If not you're good to go until it does (if ever)
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 06-17-12, 11:06 PM   #3
Chaotik
Newbie
Thread Starter
 
Join Date: Jun 2012
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks FBinNY...

Just to add some information, when I drag my nail over the crack it definitely catches.
So if it's a scratch, it's certainly a deep one.

But I will for sure keep an eye on it.
I suppose the question I have now is that if it fails on me, will it be a gradual failure resulting in a crash or would it be something I would gradually see coming (crack getting larger and wider) ?

It sounds like CF just snaps when that happens but what about alu ?
Chaotik is offline   Reply With Quote
Old 06-17-12, 11:08 PM   #4
Six jours
Senior Member
 
Join Date: Mar 2007
Bikes:
Posts: 6,401
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There is no such thing as a "cosmetic" crack in aluminum. If it's cracked, it's structural.

But that doesn't look like any crack I've ever seen in aluminum. I strongly suspect that's just a paint scratch. If you're really worried about it, you should remove the paint from the area and take a hard look at it (I'd suggest taking it to a shop, but most shops are staffed by people who don't know the first damn thing about bicycles, so...)

Oh, and yes, aluminum "just snaps". That makes it a bad material for forks, IMO, but then I've been accused of being an old codger.
Six jours is offline   Reply With Quote
Old 06-17-12, 11:31 PM   #5
jimbok1
Junior Member
 
Join Date: Sep 2010
Bikes:
Posts: 9
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Take it to bike shop. If it is bad you can e-mail Cannondale and ask about warranty coverage or look in the yellow pages for a welder that works with thin aluminum.
jimbok1 is offline   Reply With Quote
Old 06-17-12, 11:50 PM   #6
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,914
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 236 Post(s)
scratch>stress-riser>crack> is a predictable normal chain to failure in aluminum.

if you are not a friend of an aircraft lab tester for aluminum structures,
be suspicious.
fietsbob is offline   Reply With Quote
Old 06-18-12, 08:54 AM   #7
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
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
Posts: 29,437
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 100 Post(s)
There's a big difference between a crack and a scratch, and I strongly doubt it's a crack. Scratches however vary in depth, with deeper scratches having the potential of being the seeds of a future failure.

Given that fact that it's lengthwise, rather than running across the blade, I wouldn't worry about it too much. But I can't give you any assurance since all I have is the one photo. You'll have to make your own assessment.

As to how aluminum fails, it depends of the type of aluminum and the temper. Some grades are fairly ductile, and don't fail suddenly. Others, however, can be very brittle and snap with little warning.

Nobody can ever say something is safe, there's too many possibilities. But you can have some faith in the maker to use a reasonably ductile grade of aluminum for a fork, that the scratch is lengthwise, and that there's some redundancy since it's one of two blades.

The only fork blade failure I've ever seen was in a rusted steel fork, which snapped about 6" up from the axle, and did not cause a crash. The front wheel shifted but stayed attached. Ultimately you have to make your own decision, but based on what I see in the photo, I'd ride and watch.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 06-18-12, 09:12 AM   #8
gregf83 
Senior Member
 
Join Date: Jun 2008
Location: Vancouver, BC
Bikes:
Posts: 7,274
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 43 Post(s)
It doesn't look like a scratch it looks like a crack in the paint caused by an impact to the fork. If you run your fingers over both sides of the fork do you notice any difference in the shape of the tubes?

I think the only way to tell for certain if it's a crack would be to sand off the finish.

Are you sure the fork is Alum and not steel? I didn't think they made forks from aluminium. I would stick a magnet on it and see if it's steel. If it's steel I would probably leave it alone. If it's alum I would contact Cannondale and see if you can get a replacement.
gregf83 is offline   Reply With Quote
Old 06-18-12, 10:08 AM   #9
Jed19 
Senior Member
 
Jed19's Avatar
 
Join Date: Oct 2004
Bikes:
Posts: 4,228
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by gregf83 View Post
Are you sure the fork is Alum and not steel? I didn't think they made forks from aluminium.
Yeah, Cannondale made some forks from aluminum in the past. My 1994 Killer V 900 came with a beefy aluminum fork Cannondale called the Pepperoni.
__________________
Regards,

Jed
Jed19 is offline   Reply With Quote
Old 06-18-12, 10:52 AM   #10
Ira B
Senior Member
 
Ira B's Avatar
 
Join Date: Aug 2010
Location: Coupeville, WA
Bikes: 84 Raleigh Technium- 89 Shogun Mt. Bike-96 Miyata 914
Posts: 879
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I would inspect it VERY closely under bright light with a magnifying glass. If it is cracked, DO NOT ride on it as failure could be total and sudden.

I also tend to agree with post # 4 about alum being used in forks ....but then I too am an old codger.
Ira B is offline   Reply With Quote
Old 06-18-12, 11:46 AM   #11
bradtx
Senior Member
 
Join Date: Jun 2010
Location: Pearland, Texas
Bikes: Cannondale, Trek, Raleigh, Santana
Posts: 6,557
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Chaotik, That looks like a deep scratch to me. I have an '89 crit bike that has worse injuries than what appears in that photo. Of course it's up to you to determine the extent of the damage. Use a sharpie to mark the upper and lower points of the scratch, ride as you normally would and check to see if the scratch ever extends beyond the marks.

Brad
bradtx is offline   Reply With Quote
Old 06-18-12, 12:08 PM   #12
Homebrew01
Super Moderator
 
Homebrew01's Avatar
 
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Bikes: Old Steelies I made, Old Cannondales
Posts: 19,595
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 61 Post(s)
Quote:
Originally Posted by Jed19 View Post
Yeah, Cannondale made some forks from aluminum in the past. My 1994 Killer V 900 came with a beefy aluminum fork Cannondale called the Pepperoni.
Any my 3.0 criterium frame from 1988 or so has an aluminum fork.... with a somewhat scary gap between the crown & blade.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike
Homebrew01 is online now   Reply With Quote
Old 06-18-12, 07:18 PM   #13
Chaotik
Newbie
Thread Starter
 
Join Date: Jun 2012
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Homebrew01 View Post
Any my 3.0 criterium frame from 1988 or so has an aluminum fork.... with a somewhat scary gap between the crown & blade.
Do you still ride it ?
Chaotik is offline   Reply With Quote
Old 06-18-12, 07:22 PM   #14
Chaotik
Newbie
Thread Starter
 
Join Date: Jun 2012
Bikes:
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I was informed by a neighbor that Cannondale as a lifetime warranty on their frames and forks.
Here's my issues with that though:

1- I am not the original owner but my friend is so I guess I can circumvent that one.
2- The bloody bike is like 20 years old so of course, there is no sales receipt.
3- The store where it was originally purchased is 300km from where I am. So I would have to go through another AD.

How picky is Cannondale when it comes to honoring the warranty ? I read online that they are pretty good but given the circumstances described above, am I wasting my time running around with this ?

Thanks again for all your help !
Chaotik is offline   Reply With Quote
Old 06-18-12, 07:32 PM   #15
jim hughes
Senior Member
 
Join Date: May 2010
Bikes:
Posts: 461
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Even if there is a crack under there, it was obviously preceded by a scratch, indicating an impact. So I doubt Cannondale would offer to do anything for you. But that's just my guess based on this single photo and I'm not an expert.
jim hughes is offline   Reply With Quote
Old 06-18-12, 07:45 PM   #16
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Bikes: I never learned to ride a bike. It is my deepest shame.
Posts: 3,769
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I don't think Cannondale even makes a fork to fit that bike any more.

No matter- a decent replacement fork should only cost $50 or so from an LBS. You may be able to find a cheaper one used.

Edit: But I think it most likely looks like a scratch. I would ride it or get someone else's opinion who can see the fork in person.
LarDasse74 is offline   Reply With Quote
Old 06-18-12, 10:38 PM   #17
bradtx
Senior Member
 
Join Date: Jun 2010
Location: Pearland, Texas
Bikes: Cannondale, Trek, Raleigh, Santana
Posts: 6,557
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Quote:
Originally Posted by Chaotik View Post
I was informed by a neighbor that Cannondale as a lifetime warranty on their frames and forks.
If there is a problem with OEM manufacturing and/or materials. A scratch is outside of that warranty. You maybe able to get a discount on a new frameset with the trade of your frameset. Cannondale is under new ownership, I don't know what they'll do. Nashbar has some inexpensive carbon fiber forks with threaded steerers if you feel it's needed.

Brad
bradtx is offline   Reply With Quote
Old 06-20-12, 05:26 AM   #18
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
We need a much better picture from a proper camera, but it looks like a scratch from the fuzzy pic you've posted.
Kimmo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 06:56 PM.