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

Carbon fork evaluation

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.

Carbon fork evaluation

Old 05-02-19, 09:07 PM
  #1  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 1,443
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked 90 Times in 70 Posts
Carbon fork evaluation

Is this fork safe to ride? It is a Forte Axis 1" threadless fork. Has some hairline marks where the blades meet the crown. The lines almost look like they should be there, but I'd like to get a second opinion.
bonsai171 is offline  
Old 05-02-19, 09:32 PM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,960

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4153 Post(s)
Liked 3,751 Times in 2,245 Posts
What I think I see are the boarders of the crown's sub assembly and the blades. It's not uncommon for the finish (or the under top finish putty) to be more brittle then the structure. The diagonal and lengthwise marks look more to be scratches then cracks. Have you had an experienced eye look at it in person? Andy.
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 05-03-19, 03:36 AM
  #3  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 1,443
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked 90 Times in 70 Posts
Thanks. No one has looked at it yet in person. Do you think my LBS would do that as part of a safety check? I would probably ask them to look at that specifically.

Dave
bonsai171 is offline  
Old 05-03-19, 06:30 AM
  #4  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,960

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4153 Post(s)
Liked 3,751 Times in 2,245 Posts
Dave- I wouldn't expect any shop, or others, to notice these marks on your fork unless they are told first. I don't know under what service name the shop will list the inspection, our service list doesn't have a "safety check" on it. We do initial on the spot inspections for free, unless we need to take stuff apart to evaluate. But yes, a shop is a good first step in gaining knowledge and having a better founded opinion. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 05-03-19, 06:58 AM
  #5  
Bike Gremlin
Mostly harmless ™
 
Bike Gremlin's Avatar
 
Join Date: Nov 2010
Location: Novi Sad
Posts: 4,422

Bikes: Heavy, with friction shifters

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1105 Post(s)
Liked 213 Times in 127 Posts
The only way to be certain with carbon parts is scanning (ultrasound for all I know, but check with an expert).

Visual inspection, or tapping won't reveal every flaw. Which would not be a problem if the failure mode was similar to metal parts: visible cracks on the outside that grow bigger before fully cracking. With carbon it's often relatively (or perfectly) fine on the outside, before it just snaps. Not trying to do any fear mongering - though it does boil down to that, unfortunately.

If you are the first owner and had no accidents, it's probably what it looks like: surface paint scratches and nothing more. Having said that, I ride without a helmet, but find (potentially) faulty fork an unacceptably high risk. Scanning is expensive, but not as much as repairs.
Bike Gremlin is offline  
Old 05-03-19, 10:27 AM
  #6  
sch
Senior Member
 
Join Date: May 2003
Location: Mountain Brook. AL
Posts: 4,002
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 303 Post(s)
Likes: 0
Liked 135 Times in 103 Posts
Looks like a joint line to me as well, from the solid fork crown to the hollow CF fork tubes. Coin tap not likely to help because of
the abrupt change from solid to hollow. Strictly the crown may not be solid but so much more beefy than the fork tube as to be
solid like.

OTOH, I always wonder about the two CF bars I have, both of which had usage leaflets that recommend changing the bar after 3 yrs use.
I have installed only two CF forks in the last 25yrs, neither of which came with 'instructions'.
sch is offline  
Old 05-03-19, 10:57 AM
  #7  
AlmostTrick
Tortoise Wins by a Hare!
 
AlmostTrick's Avatar
 
Join Date: Feb 2006
Location: Looney Tunes, IL
Posts: 7,398

Bikes: Wabi Special FG, Raleigh Roper, Nashbar AL-1, Miyata One Hundred, '70 Schwinn Lemonator and More!!

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1549 Post(s)
Liked 941 Times in 504 Posts
I doubt many shops are going to tell you cracked CF parts, no matter how minor, are safe to continue riding. Why would they accept the liability? Better for them to play it safe. (and sell you new parts)
AlmostTrick is offline  
Old 05-03-19, 11:24 AM
  #8  
Bike Gremlin
Mostly harmless ™
 
Bike Gremlin's Avatar
 
Join Date: Nov 2010
Location: Novi Sad
Posts: 4,422

Bikes: Heavy, with friction shifters

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1105 Post(s)
Liked 213 Times in 127 Posts
Originally Posted by AlmostTrick
I doubt many shops are going to tell you cracked CF parts, no matter how minor, are safe to continue riding. Why would they accept the liability? Better for them to play it safe. (and sell you new parts)
It's not about the money, not with carbon, definitely not with forks. It's about sleeping well at night. Failure mode is often unpredictable (sudden) and total ("catastrophic").

Also, by declaring something as "good to go" when others have recommended a (n expensive) replacement, one can often gain customers. I've seen it.


When in doubt, for me the reality check method is: "would I let my kid ride this?" - and I'm not a parent that doesn't encourage climbing trees and walls and all the other good stuff. So, at least for me, recommendations are always "to the best of my knowledge".


This is all completely disregarding the law, suits and liabilities (which practically don't apply for my country, but for all I know are something to also worry about for most of the USA and EU, so bike shops most probably have that in mind when giving recommendations).

Last edited by Bike Gremlin; 05-03-19 at 11:25 AM. Reason: bid inglish
Bike Gremlin is offline  
Old 05-03-19, 11:24 AM
  #9  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times in 82 Posts
Carbon fiber bike parts have limited life and are disposable. That's a feature that costs extra.
AnkleWork is offline  
Likes For AnkleWork:
Old 05-04-19, 06:49 AM
  #10  
freeranger
Senior Member
 
freeranger's Avatar
 
Join Date: Jun 2005
Location: Kentucky
Posts: 2,571

Bikes: 06 Lemond Reno, 98 GT Timberline mtn.bike

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 417 Post(s)
Liked 685 Times in 427 Posts
If it was mine, I'd replace the fork. My peace of mind and enjoying my ride is worth more than constantly worrying about whether my fork will fail while I'm riding.
freeranger is offline  
Old 05-04-19, 08:46 AM
  #11  
Crankycrank
Senior Member
 
Join Date: Jan 2009
Location: San Diego, CA
Posts: 3,637
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 834 Post(s)
Liked 1,045 Times in 734 Posts
Always nearly impossible to diagnose CF cracks on the net. Given the facts, 1" steerer, Forte brand, would suggest this an old, low end model?? and maybe just due for replacement but as mentioned needs some expert, in person and/or special equipment to diagnose properly.
Crankycrank is offline  
Old 05-04-19, 06:59 PM
  #12  
02Giant 
Senior Member
 
Join Date: Jan 2011
Posts: 2,977
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1638 Post(s)
Liked 741 Times in 495 Posts
Bonding lines where the metal crown and the carbon fork blades are joined. When new, the joint line is bonded over with a filler, painted with a black fade, then clear coated.
I have repainted a couple of bikes with like joints not only there, but also at the tips of the fork where the insert to retain the wheel, and the carbon rear stays to the bottom bracket/seat tube joints. They haven't assploded, yet.

I think there are a lot of bikes like this, out there.

Your call, your health.
__________________
nine mile skid on a ten mile ride
02Giant is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
st3venb
Bicycle Mechanics
2
08-24-12 10:04 AM
boggy
Road Cycling
6
06-24-12 09:24 AM
stryper
Singlespeed & Fixed Gear
16
06-22-12 10:17 PM
williaty
Bicycle Mechanics
4
07-27-10 10:52 PM
fiataccompli
Bicycle Mechanics
12
05-22-10 06:48 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 -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.