Garfield Cat

I was watching the TdF highlights on you tube and in between there are informative pieces. This one caught my eyes.

I would think the U.S. experts may have more input as the U.S. spends $$$ on pure and applied research, via the aerospace industry.Your Carbon Fabre Bike Won’t Last Forever

GCN Tech – Oliver Bridgewood




The Experts:

Tom Batho (McLaren Senior Specialist, Materials Engineer)

James Marrow (Professor of Nuclear Materials Science, Oxford University)

However: no expert on Polymers (epoxy)

CrimsonEclipse

What about my steel bike?
Will it last forever?

(runs away)

Atlas Shrugged

Thanks for the informative link. What these forums need is a rational and balanced discussion regarding the merits and concerns regarding carbon fibre frame material. Hopefully some long term steel frame advocates will weigh in and offer opinions regarding the advantages and magical ride qualities of steel frames. This is especially helpful since the OP has only been a member for just under 20 years and has found a interesting subject which has not been thoroughly covered before.

Pop N Wood

Interesting question. I am considering buying a high end bike and find it impossible to cut through the bravado on this site concerning carbon components. This might not be the best site to discuss this issue seriously.

I know my Bianchi steel frame lasted 40+ years of steady riding before the spot rust got so bad I found it cheaper and less work to replace the frame than restore and paint it.

As for carbon longevity Boeing makes airliners and Lockheed fighter jets out of it, so hopefully the aerospace companies understand the life cycle before they field an aircraft. But the two big differences I see are aircraft use a mix of carbon and other materials and, once fielded, are subject to a lifetime of scheduled testing and documentation. All of this is done under the supervision of regulatory agencies. Even with that airframes age out after a certain number of landing cycles before being taken out of service. This is true regardless of material.

Bicycles are a lot more ad hoc.

KerryIrons

Agree completely. Isn't it time this topic got some serious discussion?

Iride01 

I get tired of old things, I like new things. Matters not what they are made of as long as they meet my performance goals and I can afford them. Don't know why I'd want a bike to last my lifetime. It's okay that bikes wear out at some point. It is unfortunate that there isn't any good recycling strategy for CF.

mpetry912 

also the distribution of loads, concentration of loads and stresses on a bike frame are a LOT different than on an aircraft control surface.

this looks like an excellent share, thought provoking, thank you Garfield Cat

/markp

tankist

When you steel frame rusts through replace it with a Ti one.

Pratt

I remember reading that NASA, or the USAF had contacted, I believe, Kestrel about some of their proprietary molding techniques to produce CF components,

Atlas Shrugged

Make sure you buy a tig welder with the titanium frame as they have a tendency to crack.

50PlusCycling

I like archery, and carbon fiber arrows were a revelation when they came out. Light, strong, flexible but not bendable, there are wonderful. On the negative side, if they are hit by another arrow (which isn’t uncommon), unlike wood or aluminum, they are usually destroyed beyond repair.

tankist

Thank you for the heads-up! While my Ti frame hasn't cracked yet I'd better get rid of it now before it is too late.

Maelochs

All of my bikes are probably going to outlast my ability to ride them.

Pieces like this are not really about discussion ... they are about advancing a personal preference and cherry-picking information to "prove" an opinion is "right."

The people on this site riding CF frames from 30 years ago offer more pertinent data, IMO.

All frame materials can ail ... or more accurately, any component can fail, including any frame. So?

What I like is that in the eyes of the people who favor other frame materials there is a cadre of people who think CF is the perfect, ultimate everything .... but no one else can see those people or find their posts.

Anyway ... kicked the dead horse enough for today.

scott967

My frame failed at the joint between aluminum shell and the surrounding epoxy. It's not a failure of composite material, rather the bond to the shell. The actual frame is in perfect condition, considering a 10 yo bike. Compared to steel which in my experience will show signs of rust in 10 years. That's not on steel, more a problem of coatings (paint).

scott s.
.

Eric F 

There is no perfect frame material.

Thanks for attending my TED talk.

Garfield Cat

That second expert, James Marrow qualified his discussion by deferring to "polymer science".

This, I think, is where one investigates a little further.

Try this:Polymer Science

https://www.sciencedirect.com/topics...olymer-science

Jean-Marie Lehn, in Polymer Science: A Comprehensive Reference, 2012

Polymer science has experienced a most impressive expansion in depth, breadth, and diversity through developments in its core domains as well as at the interfaces of polymer chemistry and physics with materials science, supramolecular chemistry, nanoscience, biophysics, and biology. These developments are reflected in the evolution from the original edition of Comprehensive Polymer Science to the present edition Polymer Science: A Comprehensive Reference. None of these areas can nowadays be envisaged without considering the contributions of polymer science to their own progress. At the same time and with increasing impact, scientists from the other fields contribute new findings and concepts to polymer science and many novel and topical approaches are rooted in the areas mentioned above.

And: this is why a 15 year old carbon frame isn't the same as those made today, or at least, the better carbon frames.

ofajen

You might find this interesting.


A video interview with someone who repairs hundreds of fiber-reinforced resin frames each month. He talks about the evolution of carbon fiber frame designs, some of the challenges manufacturers face that make it hard to follow best engineering practice in some cases and particular features (like carbon dropouts) that cause issues and should be avoided.

Also interesting for a retro grouch like me to realize how combining some of the new technologies has solved some of the problems. Disc brakes, for example, free up carbon wheel design from problems imposed by having to copy alloy rim dimensions. Through axles help with the dropout issue.

Anyway, the practical discussion in this video is probably useful as you shop for a new frame. Also interesting in a related video is how a lot of carbon fiber frames end up not in landfill but in a stockpile waiting to possibly be used to fix another similar frame.

Otto

Pop N Wood

Your post raises a pretty good point. Damage like that is pretty easy to spot, and like you said can be simple to fix. More importantly, at least to me, is the rider probably had ample warning something was going to fail.

Carbon doesn't seem to have an easy way to detect pending failures. I also have questions how gracefully it will be when it does.

A limited lifetime isn't really a big issue as long as one knows when the frame needs to be retired. How does one know that with a carbon part?

Wildwood 

My 3.0 pound CF frame (Ti dropouts and BB sleeve) from 2000 is still in warranty. Calfee Tetra 60cm. Has lots of tough miles on earthquake cracked California mountain roads, and from other places when it was basically my only bike ridden. The original CF fork had a issue and was replaced after 1 year, and the bike has had 2 component upgrades. Not worried about a frame failure.

As it sits today. One factory repaint years ago. The upgrades were:1. 9sp Racing Triple to 10sp compact double, new shifters, derailleurs; 2. Threaded to threadless fork/headset + skeleton brakes. Upgrades worth the expense. It has nice road feel, esp with Spec Cotton Turbos.

edit: As a 190 pound rider, I am not interested in today's weight weenie carbon bars and stems or derailleurs. I should jump on some carbon wheels for one of my bikes - have yet to try those and that's possibly my best route to more efficient pedaling.

edit Craig Calfee published some tech papers years back that I may still have in garage attic. Maybe later.......

Atlas Shrugged

Good follow up question. I have budgeted a quarter into the purchase of every carbon bicycle and perform regular and thorough tap tests. When I bought my S Works bike I decided to use a Silver Dollar because I heard if you use a actual silver (well 90%) that the tone is cleaner and more defined.


Then every 10 years I schedule a full NDT of the frame and carbon components. This money is also set aside at purchase and placed into an Index Fund. Luckily the costs for testing is dropping as market performance has been soft since my last frame purchase.

https://carbonbikedoctor.com/inspection-diagnostics/

However if I am on a longer tour or just busy with other important issues like keeping Aphids off my tomatoes I just ride my bike like millions of others and not give it a second thought.

Kai Winters

Steel frames will last forever...until they start rusting in critical areas then eventually fail
Aluminum frames will last forever...until enough cycles pass that a weakness in the material of a joint, welded, etc., weakens and fails
Titanium frames will last forever...quite possibly but the dirty little secret of the Merlin Ultra Light frames cracking at the downtube water bottle braze on points can be quite a problem...I've seen this first hand...not pretty
Carbon Fibre...cycles of stress on certain areas may eventually crack...how long...I dunno...sort of like how many licks to the center of a Tootsie Pop...the world may never know

It is likely there are hard numbers on cycles of stress related failure for advanced materials...this is what testing labs do every day...but likely that data is proprietary and never released to the public. Likely it also depends on the "load". I'm 64k/142lbs and my cycles of stress are going to be more than a clydesdale of the same height on the same frame to the point of failure. But these "points" are quite long mainly because no company wants law suits which are legit because they are selling a product with a short life span based on everyday use.

I'm a 'wrench monkey' in a local shop and have been for decades. I'm still working on 60's era bikes that have been left in unheated garages, sheds, basements, etc. and while rusty...especially the chrome plated wheels...they are still safe to ride and work pretty well...after some needed maintenance.
The same is true with older aluminum and carbon frames I service...they don't show signs of fatigue cracks, etc. even after a couple of decades of use and irregular maintenance.
However drop a carbon bike on its side just 'wrong' and on the exact spot and a crack can occur. We just refused to work on an older carbon bike a customer brought in because one chainstay was completely cracked and 'fixed' with a coating of 'something' that was applied by the previous owner who told the current owner it was fine...lol, we told him good luck but didn't want the responsibility of servicing the bike. He said he would only use it as a 'trainer' bike but it didn't matter, it was a safety issue we didn't want to be a part of in any way other than warning him of the possibility of catastrophic failure. We did note that on our work order which is archived...just in case.

I rode a Merlin Titanium frame, standard tubing not extra light, for 22 years and it was the same after 22 years of riding as the day I picked it up at the Summerville, MA facility on day one of owning it. But again I'm light, ride 'lightly', keep my bike in my home and maintained it meticulously while I owned it. So it is likely it will last for many, many decades to come.

cyccommute 

Having broken 4 frames (2 steel and 2 aluminum) as well as many steel parts and a few alloy ones, I can tell you that there is generally no warning when a metal part is going to fail. Steel, especially, doesn’t give any warning. It doesn’t bend, it doesn’t creak, it doesn’t do anything but go “Ping!” and is broken. Aluminum can sometimes creak before failure but not always. It would depend on where the aluminum failure is occurring.

The reason for the failure mode and lack of warning has to do with the material. Steel is stiff and slightly brittle. It holds on with internal cracks until such time as it can’t hold any longer and fractures…often audibly. This is shear and steel is well know to shear during failure. It holds on for a very long time until the forces cause rapid crack propagation. Think of how a spoke breaks as an example.

Aluminum is soft, not stiff, and certainly not brittle. It tends to tear rather than shear like steel. It’s generally a much slower failure process. This tearing is what can cause the creaking that is sometimes associated with failure. People often ignore the creaks…I have…only later to realize that the creaking was associated with a problem.

Titanium is going to be somewhat similar to aluminum.

There really isn’t any easy way to detect pending failure of any material. Carbon fiber’s multidirectional fiber nature is what causes the “graceful failure” that Professor Marrow was talking about. It’s unlikely that the carbon fiber can develop a crack that will propagate across the metal member like metals can. Cracks can form in the matrix…the epoxy…but once they hit a fiber, they are stopped. Carbon fiber is somewhat analogous to wood which isn’t crystalline but fibrous. It’s also much like a piece of plywood with different layers of wood running in different directions. You simply can’t crack it across the laminates because the fibers run in directions that don’t allow for crack propagation.

How does one know when a metal part needs to be retired? There isn’t really a reliable method for any material that can done in your home or even a bicycle shop. Testing of materials isn’t cheap nor easy.

wheelreason

Most bikes will outlast most cyclists...

Carbonfiberboy 

My 2000 Trek frame and fork are still in perfect condition. I took all the paint off some years ago and replaced the aluminum cable guides, which failed from electrolytic corrosion. That was from sweat dripping off my nose on long pass climbs. When I got the paint off, I rather marveled at how well the frame was built. Don't see why it won't last for a couple more generations. It still rides like new. Of the metal parts, I think I've replaced everything except for the brake calipers and dropouts. Stuff either failed, wore out, or corroded away.

tankist

Unfortunately fixing Ti cracks is much more difficult and expensive compared to ones in steel. My friend cracked his Ti bike from direct hit at high speed. He could not find anybody capable of repairing the frame for reasonable money.