Carbon frame life cycle

by Bishop   April 25, 2014  

Looking to get a towards the upper end of the price range carbon frame/bike as a summer weekend mile muncher.

One thing I'm having trouble quantifying is how long should you expect a cared for carbon frame to last.
Thanks

42 user comments

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crikey wrote:
What a load of nonsense.

Trek give a lifetime warranty on their frames, I've got a 14 year old one that's still as good as the day it was bought. People change frames because they go out of style, not for any material science reason.

Your cared for carbon frame will last at least as long as any steel or titanium frame.

How do you know your frame is as good as the day it was bought? Have you had it tested? In fact, how does anyone know how close their carbon frame is to catastrophic failure?

If a manufacturer offers a lifetime warranty, that doesn't mean the product will last a lifetime. It just means the manufacturer has estimated that the extra profit on collective sales will be greater than the cost of servicing that warranty.

"Hey..... Let's be visible out there."

Neil753's picture

posted by Neil753 [451 posts]
29th April 2014 - 1:07

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The same comment can be applied to any frame of any material, and I've broken steel and aluminium frames...

The idea that every carbon frame is minutes away from 'catastrophic failure' is one used by people who don't like them, and as above, is not related to material science.

posted by crikey [180 posts]
29th April 2014 - 5:22

10 Likes

crikey wrote:
The same comment can be applied to any frame of any material, and I've broken steel and aluminium frames...

The idea that every carbon frame is minutes away from 'catastrophic failure' is one used by people who don't like them, and as above, is not related to material science.

Absolutely!

I get tired of hearing armchair engineers telling me my carbon bike is likely to explode at any second sending shards of razor sharp carbon through my gentleman parts!

These are generally the same people who tell me I must never allow a carbon bike to get wet - "It's likely to degrade it mate" - sure, sure it will. Laughing

chrisp1973's picture

posted by chrisp1973 [57 posts]
29th April 2014 - 10:24

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Trull wrote:
you will benefit from skinny frame aerodynamics

Wuzzaht ? Deliciously gorgeous though the Volare looks, i'm not completely certain smaller but perfectly round tubes would give much aerodynamic advantage compared to bigger but more judiciously shaped fellows. Then again, i'm most definitely not a aerodynamicist nor CFD expert - wouldn't mind hearing from some though.

fukawitribe's picture

posted by fukawitribe [464 posts]
29th April 2014 - 11:21

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Carbon should last as long as any other material - longer even than aluminum, as that is subject to fatigue damage. There's no evidence that ultraviolet light damages carbon fiber, and no evidence that stiffness reduces over time.

Sources:
http://carlhart.com/how-to/how-to-care-for-carbon-bikes-and-parts-pg220.htm

http://www.ibiscycles.com/support/technical_articles/all_about_carbon/

posted by 7thGalaxy [46 posts]
29th April 2014 - 11:26

5 Likes

Just go for a frame with a lifetime warranty.

Last night I would have considered trading a very loud baby for a really nice bike.

posted by notfastenough [3310 posts]
29th April 2014 - 11:39

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There's always going to be opposing views on carbon, but you you'd have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders. We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

You certainly don't have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it's sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

"Hey..... Let's be visible out there."

Neil753's picture

posted by Neil753 [451 posts]
29th April 2014 - 12:37

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My '02 C40 hasn't turned in to a flexy noodle as yet, and there's plenty of them out there still being ridden.

posted by weenyd [18 posts]
29th April 2014 - 12:52

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Neil753 wrote:
There's always going to be opposing views on carbon, but you you'd have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders.

And I've heard the same of Aluminium, and it's probably happened with cheap steel too, I seem to remember a story a couple of weeks back of someone trying to sue Halfords when his steerer broke. It happens to all materials.

Neil753 wrote:
We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

Rather off the point, your frame material really doesn't factor into responsibility towards other road users. I pay for the emergency services and the NHS (and for my insurance for that matter) and as such I feel quite entitled to use them if I have an accident. Carbon isn't just about weight saving, you can get superior stiffness, aerodynamics, comfort, looks. What is clear about it? Why would your priorities automatically be shared by anyone?

Neil753 wrote:
You certainly don't have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it's sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

Brought to you by (insert bike manufacturer here). You could say that about ANY frame material. You can have carbon repaired quite happily, to a good standard. As with any second hand purchase, check it over carefully.

It's stronger, more durable and lighter than steel. Live with it.

posted by 7thGalaxy [46 posts]
29th April 2014 - 13:14

7 Likes

7thGalaxy wrote:
It's stronger, more durable and lighter than steel. Live with it.

Luckily I don't have to "live with it" at all. I feel much safer on a custom steel frame. My garage is a carbon free zone Wink

"Hey..... Let's be visible out there."

Neil753's picture

posted by Neil753 [451 posts]
29th April 2014 - 14:08

2 Likes

Fair enough Wink I have a classic steel frame too (in need of restoration, but it was my trusty steed for many years, and has taken much punishment). It's a joy to ride in many ways, and I fully plan to do some touring on it once it's been sorted out. But carbon isn't something to be afraid of.

posted by 7thGalaxy [46 posts]
29th April 2014 - 14:27

5 Likes

I wonder what it's like to live in fear. Fear of teh crabonz.

posted by redmeat [83 posts]
29th April 2014 - 15:01

3 Likes

Neil753 wrote:
There's always going to be opposing views on carbon, but you you'd have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders. We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

You certainly don't have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it's sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

You'd have to be pretty isolated not to have heard the same about metal frames.

It has been known for cars to fail and hurt people, by your metric you'd better not drive, get on a plane, push a supermarket trolley.............

Your point about responsibility to other road users linked to frame choice is weak at best and as for destroying a £2500 frame after "any impact" is stupidity at it's finest ( I suspect getting it checked by an official dealer might be a better call?)

Carbon, in some cases, is easier and more effective to repair than metal and will, if correctly looked after, last just as long if not longer (it doesn't corrode you see).

Yes there are shitty Chinese fake Pinarello's out there but you'd be a fool to buy one in the first place, if you can't afford a genuine bike set your sights a bit lower or save a bit harder.

I understand you're a fan of steel, I'm a fan of all bikes and great workmanship, but don't do another product down because you don't fancy or can't afford it.

chrisp1973's picture

posted by chrisp1973 [57 posts]
29th April 2014 - 15:27

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I'd like to know how many accidents were caused by catastrophic failures and how many catastrophic failures were caused by the accident.
"I fell off due to my handlebars/frame/crank snapping." Sounds better than,
"I was not looking where I was going, fell off and broken part x!"

Going back to the OP, just get a carbon frame if you want, in a few years time you'll be replacing for the next generation of disc braked electronic shifting frames anyway.

posted by Yorkshie Whippet [296 posts]
29th April 2014 - 15:30

5 Likes

My understanding is that different materials behave differently to load.

For instance aluminium is compromised with every bend, twist, vibration it is asked to absorb. Over time the material degrades and at some point, no matter what you do, it is going to fail.

Steel has a definite yield point. Below that yield point it can suck up as bending, twisting/vibration almost indefinitely. Above that yield point, then the material ages in the same way as aluminium.

Titanium is like steel, although the yield point is considerably higher.... so it can take more extreme bending etc. The challenge with this is that it also makes for a bendier frame, so manufacturers mix in alloys/treat the material in such a way to stiffen it, which also lowers the respective yield point. So.. you can have a ti frame for life, but it rides like poop, or one that rides well, but has a similar life expectancy to steel.

Carbon, as I understand it is a yes/no material. It'll bend, twist, vibrate within a range indefinitely. Push it beyond its limit and it will fail spectacularly, and rapidly. The challenge with carbon is as mentioned, blunt impacts can compromise the material and right now we are still in the realms of developed understanding of the long term degradation of epoxies.
The great thing about carbon is that it is so un-precious its untrue. Punch a big hole in your frame... as long as you fix it, its no bother at all.
Its certainly not the super fragile material some make it out to be.

posted by Jimmy Ray Will [305 posts]
29th April 2014 - 15:45

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Jimmy Ray Will wrote:

Carbon, as I understand it is a yes/no material. It'll bend, twist, vibrate within a range indefinitely. Push it beyond its limit and it will fail spectacularly, and rapidly. The challenge with carbon is as mentioned, blunt impacts can compromise the material and right now we are still in the realms of developed understanding of the long term degradation of epoxies.
The great thing about carbon is that it is so un-precious its untrue. Punch a big hole in your frame... as long as you fix it, its no bother at all.
Its certainly not the super fragile material some make it out to be.

Everything fails beyond its limit, thats why it's a limit...
We know plenty about long term epoxy degredation, they've used CF in aerospace & F1 with enough research into CF in them to cover what bikes require.

At the end of the day people will have a material of preference, though usually the steel luddites are quick to shout down CF as fragile and weak.

glynr36's picture

posted by glynr36 [468 posts]
29th April 2014 - 15:54

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I wouldn't worry - 6 to 12 months after purchase the bike companies will realise that the headset, BB and brake mounting standards they used to use are all shit, and then new ones are like, so much better it's unreal and we all need to upgrade or be stuck with a 2 wheeled betamax.

Works for Apple, no?

posted by allez neg [4 posts]
29th April 2014 - 16:04

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allez neg wrote:
I wouldn't worry - 6 to 12 months after purchase the bike companies will realise that the headset, BB and brake mounting standards they used to use are all shit, and then new ones are like, so much better it's unreal and we all need to upgrade or be stuck with a 2 wheeled betamax.

Works for Apple, no?

Only too well *as he pens this reply on his brand new iPhone 5S* - damn that company, it's like they posess me! Angry

chrisp1973's picture

posted by chrisp1973 [57 posts]
29th April 2014 - 16:13

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Many of the comments here are based on made-up facts and urban cycling legends. As someone has already mentioned, many modern aircraft are made of CF because it is the lightest material that offers superlative levels of structural integrity.
Anyone suggesting that CF is more likely to fail is quite simply mistaken.

posted by Adrien de la touche [1 posts]
29th April 2014 - 16:23

9 Likes

Many aircraft structures are indeed made of carbon fibre because of its structural integrity but unlike bicycle frames there is no intention of using them again after a crash.

You can straighten a steel frame after a crash. I like the fact that my steel frame has at least this one particular characteristic that cannot be matched by carbon.

Not made up and not an urban myth.

Shay

posted by shay cycles [233 posts]
29th April 2014 - 17:56

3 Likes

Gordy748 posted:

"Carbon has a fatigue life and, over time, flexes more and more every pedal stroke. Every time this happens, it absorbs (fractionally) more and more watts produced by the rider. For a pro, the point at which the frame is unacceptably flexible will happen a lot sooner than a sportive rider."

sorry, this goes against current technical understanding and material behaviour of composites (which is another reason they are now used in passenger aircraft)

one of the big bonuses of carbon fibre composites is that in normal use (in the design envelope) they do not fatigue (unlike aluminium alloy) and withstanding catastrophic impacts (crashes) or environmental degradation (exposure to UV, road salt, etc. which can be guarded against with good finishing) should easily outlast metallic alloy framesets

of course, this assumes good quality control during manufacturing and no in-built 'design flaws' to the composite design or galvanic corrosion from in-moulded metallic alloy hard points (this is why manufacturers are moving to all carbon frames with carbon dropouts, headset cups and bottom bracket tubes)

posted by hampstead_bandit [169 posts]
29th April 2014 - 19:15

1 Like

There's been some discussion, suggesting that if aircraft are made of carbon then carbon bike frames must be just as safe, so I thought I'd just quote what carbon-bike-check.com say on the subject, over in Germany.

"A plane consists of large, massive components which reinforce and support each other. Most are large machine-made components which help reduce inconsistencies. Each part is checked and tested after assembly as a whole. And that is for example the difference between an Airbus and a bicycle. An Airbus is tested and tested and tested. The aviation standards define exactly what, how and how often a component is to be tested. And for bikes, is there nothing? Actually, there are standards but these apply to Type Testing meaning the design is tested using samples before production but they do not apply to the production itself. They are also not mandatory. "

They also go on to say that "a defect-free frame, fork, stem, etc. does not exist", and that "many failures could have been prevented if testing had been carried out beforehand". Ok, CBC's business is the testing and analysis of composite materials, but it certainly makes sobering reading.

"Hey..... Let's be visible out there."

Neil753's picture

posted by Neil753 [451 posts]
29th April 2014 - 20:44

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I'm fairly sure that no one said it would fail....just that it loses its stiffness.

As for aircraft, yes, it's used as an alternative to....aluminium.....which the thread seems to agree has a low stress life.

I'm not against carbon, I have carbon, I use carbon, but I still believe it has a limited life in use in the real world...just as that expensive re-enamel does on steel.

All Campag

posted by Flying Scot [594 posts]
29th April 2014 - 20:45

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I crashed my carbon TT bike at 25mph. It just sucked it up and Im still racing it 3 years later.

I have carbon forks that are donkeys years old too Smile

posted by ilovemytinbred [164 posts]
29th April 2014 - 21:32

2 Likes

Some bizarre comments on here - clearly a little knowledge is a dangerous thing.

How long will a carbon frame last?

Indefinitely, as long as you don't crash it or leave it exposed to the elements on a permanent basis (this last part strangely, is true of most bike frame materials).

If you feel the urge to crash your bike regularly buy something else but but recognise than nothing can be fixed 'good as new'. What ever you buy don't leave it out in the sun, rain etc - but then if you're looking at high end carbon I'm guessing you weren't intending to?

I have carbon, steel and aluminium. The steel is 20+ years old and weirdly has rusted. The aluminium has unusually failed to snap yet (15 years old) and the carbon is still going strong despite only having paint to act as a sunscreen. I don't have a titanium bike yet, or a beard but who knows, both of those things may be in my future.

posted by Nixster [86 posts]
29th April 2014 - 21:37

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hampstead_bandit wrote:
sorry, this goes against current technical understanding and material behaviour of composites (which is another reason they are now used in passenger aircraft)

one of the big bonuses of carbon fibre composites is that in normal use (in the design envelope) they do not fatigue (unlike aluminium alloy) and withstanding catastrophic impacts (crashes) or environmental degradation (exposure to UV, road salt, etc. which can be guarded against with good finishing) should easily outlast metallic alloy framesets

Nope, and I talked to the Boeing engineer who worked out how to bond the 787's wings to the fuselage to help me explain better.

The 787's wings are designed to flex within a certain limit (she said about 25 feet at the tips in normal flight, but can tolerate significantly more in rough weather). After that, they fail. A crash will also render the wings inoperable (this is not very surprising).

There's a difference, though, between something that is designed to flex and something that's designed to remain rigid, e.g. a bicycle frame or an oar for rowing. While carbon is a flexible material, the bonding agent (resin) isn't. When a frame flexes, it's because it's been built with less resin at certain points to facilitate movement (say, for vertical compliance to increase comfort). In hundreds or thousands of cycles (pedalling or rowing) the epoxy that keeps the structure rigid is subject to miniscule stresses that gradually break it apart and allows the structure to flex more and more.

So between a 787's wings and a Venge, it's the required stiffness in the bike that causes more stress on the resin and so fatigues the structure quicker. This doesn't make the frame unridable or liable to break at any minute, it just means you won't go as fast on an old bike than you would on a new one.

posted by Gordy748 [89 posts]
29th April 2014 - 22:25

0 Likes

talking about forks, but you get the idea...

http://velonews.competitor.com/2011/07/bikes-and-tech/technical-faq/tech...

"I have tested a lot of steel (mostly True Temper brand tubes) and of course carbon (lots of brands) in fatigue tests and also load-to-fail tests. In high fatigue loading, the carbon forks would eventually lose some stiffness (as much as 5 percent) after many thousands of cycles to represent many years of actual riding conditions. So I would not say the forks would last forever at high loading. You don’t hit high loads on most of your rides though … You should get a lifetime of JRA riding (just riding along).

Steel forks did not lose any stiffness in the fatigue tests. They are typically kind of over built so they never got stressed past the endurance limit (about 50 percent of ultimate tensile strength). In load-to-fail tests, the steel forks bend until they crack, or we would stop when the fork had bent more than 10-20 percent (un-useable).”

So there you go. Sleep easier.
— Lennard"

posted by ilovemytinbred [164 posts]
29th April 2014 - 22:42

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I don't think we can draw many conclusions from that, he doesn't give us any idea of what the 'high fatigue loading' was, or any idea what 'many thousands of cycles to represent many years' means - are we talking 20 years? 40?. How close to the limit was it pushed?

posted by 7thGalaxy [46 posts]
30th April 2014 - 10:00

1 Like

[quote=Gordy748
So between a 787's wings and a Venge, it's the required stiffness in the bike that causes more stress on the resin and so fatigues the structure quicker. This doesn't make the frame unridable or liable to break at any minute, it just means you won't go as fast on an old bike than you would on a new one.

By that logic, the stiffer bicycle frame with more resin would be subject to less flexing of the resin and a longer lifespan than the more flexible, resin-light aeroplane wing.

posted by Nick T [817 posts]
30th April 2014 - 10:10

3 Likes

Sooooooo booooooring Yawn can't believe I read all of this.

I say this

Well I say this

But I say this

You're all wrong I say this

Yawn

posted by jellysticks [83 posts]
30th April 2014 - 15:55

1 Like