Do carbon frames become more flexible over time?
#1
Senior Member
Thread Starter
Join Date: Apr 2006
Posts: 252
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Do carbon frames become more flexible over time?
A newbie friend said he'd heard that carbon frames become more flexible over time, so he asked me about it. Before I laughed it off and told him it was silly, I thought I should do a quick Google, and found this:
"Carbon-fiber components actually do get softer with use. As the component flexes, the internal fibers break free of the surrounding resin and delaminate invisibly. When TOUR magazine tested carbon forks, they found that after 100,000 test cycles, some forks had lost a significant amount of their stiffness. Today, the European Union standards for fatigue resistance specify how much stiffness a carbon component may lose over the test cycle."
https://janheine.wordpress.com/2012/0...es-going-soft/
**********
"Carbon-fiber components actually do get softer with use. As the component flexes, the internal fibers break free of the surrounding resin and delaminate invisibly. When TOUR magazine tested carbon forks, they found that after 100,000 test cycles, some forks had lost a significant amount of their stiffness. Today, the European Union standards for fatigue resistance specify how much stiffness a carbon component may lose over the test cycle."
https://janheine.wordpress.com/2012/0...es-going-soft/
**********
#3
Senior Member
#5
Senior Member
Join Date: Aug 2009
Location: Burnaby, BC
Posts: 4,144
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
I've read that as well. I would guess that these standards should be available somewhere online, if someone would go and look for them.
#6
Reasonably Slow...
A newbie friend said he'd heard that carbon frames become more flexible over time, so he asked me about it. Before I laughed it off and told him it was silly, I thought I should do a quick Google, and found this:
"Carbon-fiber components actually do get softer with use. As the component flexes, the internal fibers break free of the surrounding resin and delaminate invisibly. When TOUR magazine tested carbon forks, they found that after 100,000 test cycles, some forks had lost a significant amount of their stiffness. Today, the European Union standards for fatigue resistance specify how much stiffness a carbon component may lose over the test cycle."
https://janheine.wordpress.com/2012/0...es-going-soft/
**********
"Carbon-fiber components actually do get softer with use. As the component flexes, the internal fibers break free of the surrounding resin and delaminate invisibly. When TOUR magazine tested carbon forks, they found that after 100,000 test cycles, some forks had lost a significant amount of their stiffness. Today, the European Union standards for fatigue resistance specify how much stiffness a carbon component may lose over the test cycle."
https://janheine.wordpress.com/2012/0...es-going-soft/
**********
#7
Administrator
Join Date: Feb 2005
Location: Delaware shore
Posts: 13,558
Bikes: Cervelo C5, Guru Photon, Waterford, Specialized CX
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1106 Post(s)
Liked 2,180 Times
in
1,470 Posts
#10
Senior Member
i would have thought CF becomes more brittle over time...hence the 'sploding.
__________________
2014 Specialized Roubaix2003 Interloc Impala2007 ParkPre Image C6 (RIP)
2014 Specialized Roubaix2003 Interloc Impala2007 ParkPre Image C6 (RIP)
#11
pan y agua
Join Date: Aug 2005
Location: Jacksonville
Posts: 31,304
Bikes: Willier Zero 7; Merlin Extralight; Calfee Dragonfly tandem, Calfee Adventure tandem; Cervelo P2; Motebecane Ti Fly 29er; Motebecanne Phantom Cross; Schwinn Paramount Track bike
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1447 Post(s)
Liked 728 Times
in
373 Posts
This take from an Alpha Q engineer in Leonard Zinn's column may be a bit more objective. https://velonews.competitor.com/2011/...g-tools_181993
According to him, CF forks can lose up to 5% stiffness after thousands of cycles of high fatigue loading involving forces exceeding what is routinely encountered riding around.
And given that the CF frame is going to be stiffer to start, it's still going to be fine for years and years of riding. Pretty much a non issue as a practical matter.
According to him, CF forks can lose up to 5% stiffness after thousands of cycles of high fatigue loading involving forces exceeding what is routinely encountered riding around.
And given that the CF frame is going to be stiffer to start, it's still going to be fine for years and years of riding. Pretty much a non issue as a practical matter.
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
#13
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 89 Post(s)
Tagged: 0 Thread(s)
Quoted: 18883 Post(s)
Liked 10,646 Times
in
6,054 Posts
#14
I like beans
Join Date: Feb 2007
Location: Meffa, MA
Posts: 3,336
Bikes: Tarmac Pro, Bianchi Zurigo, Raleigh Gran Sport, Fuji Del Rey, Ironman Centurion
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Just when I get curious if things have changed and it's safe to post over here again, I come across this stuff...
#15
Senior Member
Join Date: Oct 2004
Location: Seattle
Posts: 3,248
Bikes: Kuota Ksano. Litespeed T5 gravel - brilliant!
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 4 Times
in
4 Posts
That would be awesome. Imagine bragging to your friends that your legs are so strong you actually tore the fibers apart and delaminated the frame. It makes me almost want to abuse my CF bike just to see if I can break it. Definitely worth the bragging rights.
#16
VFL For Life
Join Date: Feb 2005
Location: Knoxville, TN
Posts: 51,235
Bikes: Velo Volmobile
Mentioned: 780 Post(s)
Tagged: 2 Thread(s)
Quoted: 28627 Post(s)
Liked 1,858 Times
in
1,320 Posts
Someone should blog about this.
#17
Senior Member
Join Date: Dec 2005
Posts: 7,848
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 2 Times
in
2 Posts
Fibers and all the glue they put in the carbon gets harder with time not softer. Steel for some reason does the opposite. As somebody said it should more brittle not softer.
#18
Speechless
Join Date: Jun 2011
Location: Central NY
Posts: 8,842
Bikes: Felt Brougham, Lotus Prestige, Cinelli Xperience,
Mentioned: 22 Post(s)
Tagged: 1 Thread(s)
Quoted: 163 Post(s)
Likes: 0
Liked 39 Times
in
16 Posts
Cake gets harder over time, while pie turns to mush. Clearly this must be relevant.
#19
Senior Member
Join Date: Jul 2005
Location: Boulder County, CO
Posts: 4,398
Bikes: '80 Masi Gran Criterium, '12 Trek Madone, early '60s Frejus track
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 514 Post(s)
Liked 450 Times
in
338 Posts
In my experience with an '07 TCR Composite, this is true. Confirmed by a co-worker whose team was sponsored by Giant and a knowledgeable lady I met at a coffee stop. Her TCR Composite turned to mush over time, too. Symptoms were visible sagging of frame when I sat on it, increasingly sloppy handling, increasing susceptibility to speed wobble, increasingly difficult to control in crosswinds, and loss of sprint. Nanofiber and higher compression rates used in the better contemporary frames is supposed to address this.
Think about it. Carbon fiber and epoxy are inert. They can't change chemically, but stress can break them (in theory). I'm going with theory. And my own observation.
Regarding steel, I've heard that a well brazed joint actually gets harder with use.
Think about it. Carbon fiber and epoxy are inert. They can't change chemically, but stress can break them (in theory). I'm going with theory. And my own observation.
Regarding steel, I've heard that a well brazed joint actually gets harder with use.
Last edited by oldbobcat; 10-29-12 at 09:28 PM.
#21
I eat carbide.
Join Date: Jan 2006
Location: Elgin, IL
Posts: 21,627
Bikes: Lots. Van Dessel and Squid Dealer
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1325 Post(s)
Liked 1,306 Times
in
560 Posts
This is fun.
Carbon frames are layers of fibers and resins. Over time small voids in the matrix can lead to "localized de-lamination" for lack of a better term. a broken fiber in a mesh of hundreds of thousands...yay. a hundred broken fibers at different points....thousands...over time if the construction techniques (molding and joint making) aren't well designed, thought out or executed they could lead to more microscopic voids or fiber breaks that would lead to a "softening" of the assembly.
In essence though - a non-issue for the vast majority of the frames and racers out there. The changes in layup techniques, frame shape, and resins account for large changes in the stiff "feel" of newer frames. Enough that it can be easy to get off of a frame from 3-5 years ago and get on a new one and mistakenly assume that the old one had "gone soft" because the difference in feel is just that drastic.
Carbon frames are layers of fibers and resins. Over time small voids in the matrix can lead to "localized de-lamination" for lack of a better term. a broken fiber in a mesh of hundreds of thousands...yay. a hundred broken fibers at different points....thousands...over time if the construction techniques (molding and joint making) aren't well designed, thought out or executed they could lead to more microscopic voids or fiber breaks that would lead to a "softening" of the assembly.
In essence though - a non-issue for the vast majority of the frames and racers out there. The changes in layup techniques, frame shape, and resins account for large changes in the stiff "feel" of newer frames. Enough that it can be easy to get off of a frame from 3-5 years ago and get on a new one and mistakenly assume that the old one had "gone soft" because the difference in feel is just that drastic.
__________________
PSIMET Wheels, PSIMET Racing, PSIMET Neutral Race Support, and 11 Jackson Coffee
Podcast - YouTube Channel
Video about PSIMET Wheels
Podcast - YouTube Channel
Video about PSIMET Wheels
#22
Senior Member
Thread Starter
Join Date: Apr 2006
Posts: 252
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I appreciate all the replies.
I don't know much about tech stuff, especially carbon.
I don't suppose anyone can find a link to the Tour Magazine test? I can't.
I don't know much about tech stuff, especially carbon.
I don't suppose anyone can find a link to the Tour Magazine test? I can't.
#23
Senior Member
Thread Starter
Join Date: Apr 2006
Posts: 252
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
This take from an Alpha Q engineer in Leonard Zinn's column may be a bit more objective. https://velonews.competitor.com/2011/...g-tools_181993
According to him, CF forks can lose up to 5% stiffness after thousands of cycles of high fatigue loading involving forces exceeding what is routinely encountered riding around.
And given that the CF frame is going to be stiffer to start, it's still going to be fine for years and years of riding. Pretty much a non issue as a practical matter.
According to him, CF forks can lose up to 5% stiffness after thousands of cycles of high fatigue loading involving forces exceeding what is routinely encountered riding around.
And given that the CF frame is going to be stiffer to start, it's still going to be fine for years and years of riding. Pretty much a non issue as a practical matter.
#24
Uber Goober
I had just assumed that it was the riders getting fatter and weaker that was the issue, not that the bikes got weaker and flexier.
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."
"be careful this rando stuff is addictive and dan's the 'pusher'."