Carbon frame reliability

pliptrot · May 2007

There seem to be many concerns in this - and other cycling fora - about composite frames. Reliability is undoubtedly in question, with some posters having had 2 similar frames fail. Are there any data bases/objective analyses/researches done into this? Chris Juden, who is the technical officer for the CTC and one of the few pundits in the cycling media worth listening to, (with apologies to others, in particular those who write for Cycling Plus), is less than impressed with composites, and I was wondering if he's on to something.

Any comments?

Garybee · May 2007

The fork is a very highly stressed component, as it is only attatched at one end, yet people seem perfectly happy to ride a carbon forked bike. It seems very odd to me that despite this people constantly question the reliability of carbon frames.

Hypocrisy is only a bad thing in other people.

method · May 2007

I wouldn't take what you read on here or another forum to be the general opinion about carbon frames. Reliability isn't under question, if you crash or drop something on it, thats one thing, but carbon frames that just fail aren't very common. Even many steel folks ride carbon forks, they don't seem to bothered.

monty_dogcp · May 2007

Hmmm - the CTC now calling themselves a technical authority!! On what, beards and saddle bag flap lengths? Anything that isn't made out of steel in the CTC's view is probabably viewed as 'untested' technology because it wasn't invented in the 19th century. I wouldn't trust most people in the cycle trade on their knowledge of composites - those that call plastic mouldings, 'resin' for example and wouldn't know polyamide from polyfilla. Nobody's forcing you to buy a composite frame - if you don't like the sound of it, then don't buy one! I expect I'll get flamed by CTC beardies and crusty types, but hey, I'll take it on my clean-shaven chin!

Fnaar · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Monty Dog

Hmmm - the CTC now calling themselves a technical authority!! On what, beards and saddle bag flap lengths? Anything that isn't made out of steel in the CTC's view is probabably viewed as 'untested' technology because it wasn't invented in the 19th century. I wouldn't trust most people in the cycle trade on their knowledge of composites - those that call plastic mouldings, 'resin' for example and wouldn't know polyamide from polyfilla. Nobody's forcing you to buy a composite frame - if you don't like the sound of it, then don't buy one! I expect I'll get flamed by CTC beardies and crusty types, but hey, I'll take it on my clean-shaven chin!
<hr height="1" noshade id="quote"></blockquote id="quote">
Why not have a goatee composite, where clean-shavenness meets hairy bits?

kinckers kanckers konckers [:D]

Unknown · May 2007

Carbon will fail catastrophically if you stare at it for too long, aluminium will disintegrate after 96827 pedal strokes, integrated shifters will break and leave you stranded miles from home, indexing will need to be adjusted after every second corner, spokes for factory built wheels will cost œ96.99 each and you will have to wait eighteen months for a replacement, any saddle not made of leather will give you an incurable disease of the arse, etc etc etc.

The only reliable bike is a 1950's Ephgrave made of pig iron with a Cyclo three speed derailleur. Everyone knows that.

Nobody ever got laid because they were using Shimano

andrewgturnbull · May 2007

Hi there.

My '98 oclv is still going strong - after a good few years of turbo trainer abuse too... How long do you want from a race frame?

Thats my subjectivity. Can you let me know with what objectivity you state that reliability is undoubtedly in question?

Cheers, Andy

http://www.stirlingtri.co.uk

pliptrot · May 2007

It would take a rather churlish attiude to suggest that anyone browsing this forum -and others- wouldn't come away with the idea as I outlined in my original text. I was rather hoping to avoid people taking cheap shots at the CTC, but then commenting from a position of knowledge normally precludes that sort of behaviour. A little while ago cycling weekly ran a series of columns on the failure of carbon forks, and tales of this seem to be prevalent. I didn't state that I don't like the sound of composites- they are used widely in aircraft and I spend more time than most on those- I was merely trying to establish if these things are likely to be unreliable; however that may be defined.

But thanks for all your learned comments, some of them being the equivalent of being shouted at by passing motorists. No doubt they think that's funny, too.

Pjl

rustychisel · May 2007

You set up the question, invoked the authority of the CTC (???), questioned the basis for that authority, asked for comments; then shoot back when such comment is given with a snippish 'passing car' comment.

What is it you ACTUALLY ARE ASKING, then?

Disclaimer: I have owned 2 steel bikes which broke, 3 steel forks fractured or broken, and have never seen failure in any carbon component on any our our* bikes.

* 'our' means my partner and I currently own and ride a fleet of 6 bikes, all of which I maintain.

- - - - - - - - - - - - - - - - - - - - - - - - - - - -
I'm only escaping to here because the office is having a conniption

bhm100 · May 2007

As others have said, probably the most critical frame component is the front fork and there are loads of carbon ones around. A failure there is very likely to put you face down in the road, so I'd expect any material unreliability to show up pretty quickly, wouldn't you ?

With any emerging technology there's always a learning curve for manufacturers. (that's as far as bike frames are concerned - composites are pre-war so have been around for at least 50+yrs) Couple that with the relative expense of CF frames, and it's tempting to knock a few out - after all, you only need a paintbrush, some thermosetting resin and CF matting, don't you ?

I suspect that's where the problems come in - exactly how they did in the early days with composites when they were adopted in the chemical industry and some manufacturers jumped in without fully understanding what they were doing.

So I'd expect some failures along the way, just as there were with early Al frames and probably steel frames at some point - it's just that we've forgotten all about those failures. And if a steel or Al frame fails now, it's just not news-worthy... everyone's seen it before.

Like rustychisel, out of the 3 last frame materials I've had - Steel/Al/CF - only the steel one broke, and with far less mileage on it than the Al or CF ones. (tempting fate ?)

wotbus@ · May 2007

[:)] Uhhhh, the only frame failure I have had was a cracked down-tube right next to head-tube butt joint on a '94 Reynolds 531 "Hand Made in England" Dawes Super Galaxy. OK, I accept these things happen but you can imagine my surprise when I heard from my supplier, who agreed to exchange it under the lifetime guarantee, to say "That's where they all go"!!![:I]
It was replaced no problem - but - before each ride I am now checking everywhere for cracks, and luggage is now measured in grams instead of kilograms (which can't be a bad thing) [:D]
So what do we have here, doubts about the reliability of carbon composite. Well there are not too many modern airliners with riveted aluminium wings these days and a large percentage of light planes and gliders are almost COMPLETELY made from it[;)]
I don't think composite frames have been with the cycling fraternity long enough to begin drawing parallels with regard to reliability, and even if this were the case lots of people would still prefer composite because of the benefit.
Almost all of British ingenuity and invention lost out to foreign designers because we couldn't evolve past the "steel with a Union flag on it" situation. (anyone remember names like BSA, AJS, Velocette).
My point is this: Why choose composite to voice concern when Titanium is supposed to simply disintegrate if it gets wet (anyone remember hearing that one too) [:D]
Relax everybody - tighten your toe-straps and ride. If worried about your new composite bike just polish it and look at it. Throw your leg over your good old British steel and ride, ride, without a care.
 (but check it for cracks when you get home)[:0]

Edits typo.

Unknown · May 2007

Ive been riding and racing carbon forks and frames (mtb and road) since 2001, never had, or seen a frame or (total carbon) fork failure, other than the one that had a head on with a car but i guess thats acceptable.

Saying that though Ive worked and made stuff from CF and its a real pig to work with, I personally wouldnt use any of the cheaper lower end CF parts or frames

Unknown · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Smokin Joe

Carbon will fail catastrophically if you stare at it for too long, aluminium will disintegrate after 96827 pedal strokes, integrated shifters will break and leave you stranded miles from home, indexing will need to be adjusted after every second corner, spokes for factory built wheels will cost œ96.99 each and you will have to wait eighteen months for a replacement, any saddle not made of leather will give you an incurable disease of the arse, etc etc etc.

The only reliable bike is a 1950's Ephgrave made of pig iron with a Cyclo three speed derailleur. Everyone knows that.

Nobody ever got laid because they were using Shimano
<hr height="1" noshade id="quote"></blockquote id="quote">

[:)][:D] is I think all I have to offer on the question, being neither a materials expert nor a frame builder. That said, I imagine that the key issue is longevity and that as always will depend to an extent on how used/abused and how well cared for. And who wants a bike to last more than a few years: am I the only person who simply gets bored with 'em after a few MONTHS?

a materials

d.j.
"Like a true nature's child,
We were born,
Born to drink mild"

nmcgann · May 2007

I have no opinions either way on CF reliability.

What I do know is that it is extremely fragile - a chain that went down the inside of the inner ring and jammed on my bike ripped a big lump of CF out of the chainstays. That would only have been a paint scratch on a steel or Ti frame and a small chip on an ally frame, not a write-off (just patched with epoxy for now).

With my experience so far there is no way I would buy a full carbon frame - I'd buy Ti if I had a serious frame budget.

Neil

alan_sherman · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">a chain that went down the inside of the inner ring and jammed on my bike ripped a big lump of CF out of the chainstays. That would only have been a paint scratch on a steel or Ti frame and a small chip on an ally frame, not a write-off (just patched with epoxy for now).<hr height="1" noshade id="quote"></blockquote id="quote">

Funny enough I've only thrown away one frame - for the exact same reason as you said. However mine was steel. The frame was holed and a crack propagated around the chainstay. Wasn't worth getting fixed as it was a bonded raleigh dyna-tech. So the frame went for recycling. How many of us would actually fix a frame, get a respray and all that when you can buy a whole new frame for not much more?

Cyclist, public transport passenger, pedestrian, driver, motorcyclist.
I get on OK with myself, so why can't we all get on with each other?

nmcgann · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by alan sherman

<blockquote id="quote">quote:<hr height="1" noshade id="quote">a chain that went down the inside of the inner ring and jammed on my bike ripped a big lump of CF out of the chainstays. That would only have been a paint scratch on a steel or Ti frame and a small chip on an ally frame, not a write-off (just patched with epoxy for now).<hr height="1" noshade id="quote"></blockquote id="quote">

Funny enough I've only thrown away one frame - for the exact same reason as you said. However mine was steel. The frame was holed and a crack propagated around the chainstay. Wasn't worth getting fixed as it was a bonded raleigh dyna-tech. So the frame went for recycling. How many of us would actually fix a frame, get a respray and all that when you can buy a whole new frame for not much more?

Cyclist, public transport passenger, pedestrian, driver, motorcyclist.
I get on OK with myself, so why can't we all get on with each other?
<hr height="1" noshade id="quote"></blockquote id="quote">

Yes, the frame was œ200 off ebay brand new (Van Nicholas vardar) - I wasn't too gutted. I haven't got any frames I wouldn't skip if damaged.

Neil
Neil

Gary D · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Smokin Joe

Carbon will fail catastrophically if you stare at it for too long, aluminium will disintegrate after 96827 pedal strokes, integrated shifters will break and leave you stranded miles from home, indexing will need to be adjusted after every second corner, spokes for factory built wheels will cost œ96.99 each and you will have to wait eighteen months for a replacement, any saddle not made of leather will give you an incurable disease of the arse, etc etc etc.

The only reliable bike is a 1950's Ephgrave made of pig iron with a Cyclo three speed derailleur. Everyone knows that.

Nobody ever got laid because they were using Shimano
<hr height="1" noshade id="quote"></blockquote id="quote">

That was reeeealllly funny - thanks [:D] [:D] [:D] [:D]

As has been mentioned, within a few years, we will all be flying around on airplanes that are made almost entirely of composite materials glued together - just like Airfix models![:0]
I am sure the wing of a passenger airliner is subjected to far greater stresses than a bike frame - so I sincerely hope carbon fibre is not unreliable [;)]

Gary.

Must try harder....

Birillo · May 2007

On the other hand, there's carbon and stuff that looks like carbon (on the outside at least).

http://www.cyclingnews.com/sponsors/ita ... olnago.php

bike_the_planet · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Gary D
As has been mentioned, within a few years, we will all be flying around on airplanes that are made almost entirely of composite materials glued together - just like Airfix models![:0]
I am sure the wing of a passenger airliner is subjected to far greater stresses than a bike frame - so I sincerely hope carbon fibre is not unreliable [;)]

Gary.
<hr height="1" noshade id="quote"></blockquote id="quote">

The introduction of Carbon Fibre into the aerospace industry was not without criticism. One of the big problems with CF and composites is: how do you recognise signs of early failure? With aluminium, which has no endurance limit, fatigue is eventually inevitable. However, it displays tell-tale signs such as micro-cracking which can be picked up by the regular and meticulous inspection processes that are a requirement for aircraft. Although carbon fibre and composites don't exhibit fatigue failure, there are other failure mechanisms associated with these materials, and many of them are catastrophic (ie without warning).

With use in aircraft, many of these subsytems are designed to be replaceable in the field on a regular basis. And they are replaced.

How often do you inspect and replace your CF bike frame/components for early failure signs??? Most people don't bother. Most people wouldn't have a clue as to what to look for anyway.

Sure, steel can fail too. But if a steel frame is designed well and built with a modicom of care, it is extremely reliable.

I guess it all depends on your detal insurance...

As for the cheap shot at Chris Juden - beard or no beard, I believe the guy is a graduate mech eng from Cambridge. I think he might just have opinions that may well be worth listening to...

Unknown · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by bike_the_planet

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Gary D
As has been mentioned, within a few years, we will all be flying around on airplanes that are made almost entirely of composite materials glued together - just like Airfix models![:0]
I am sure the wing of a passenger airliner is subjected to far greater stresses than a bike frame - so I sincerely hope carbon fibre is not unreliable [;)]

Gary.
<hr height="1" noshade id="quote"></blockquote id="quote">

The introduction of Carbon Fibre into the aerospace industry was not without criticism. One of the big problems with CF and composites is: how do you recognise signs of early failure? With aluminium, which has no endurance limit, fatigue is eventually inevitable. However, it displays tell-tale signs such as micro-cracking which can be picked up by the regular and meticulous inspection processes that are a requirement for aircraft. Although carbon fibre and composites don't exhibit fatigue failure, there are other failure mechanisms associated with these materials, and many of them are catastrophic (ie without warning).

With use in aircraft, many of these subsytems are designed to be replaceable in the field on a regular basis. And they are replaced.

How often do you inspect and replace your CF bike frame/components for early failure signs??? Most people don't bother. Most people wouldn't have a clue as to what to look for anyway.

Sure, steel can fail too. But if a steel frame is designed well and built with a modicom of care, it is extremely reliable.

I guess it all depends on your detal insurance...

As for the cheap shot at Chris Juden - beard or no beard, I believe the guy is a graduate mech eng from Cambridge. I think he might just have opinions that may well be worth listening to...
<hr height="1" noshade id="quote"></blockquote id="quote">
I think you'll find that a fair few of the people involved in the carbon fibre industry have a passing knowledge of engineering too.

Nobody ever got laid because they were using Shimano

monty_dogcp · May 2007

You'll also find a few other people around here who are also engineering graduates and have pretty extensive experience of materials and composites, particularly in the aerospace and related industries used in far more demanding applications than bike frames. Professionally speaking, being a Cambridge engineering graduate and having reached the heady heights of CTC Technical Officer doesn't count for much in my book, but within 20 feet of me, I have about 10 guys who design bits for fighter planes - I think I know whose professional experience I'd rely on.

sloboy · May 2007

For me this comes down more to a question of "who would I trust to design and build a CF frame that was fit for purpose".

That's a tricky question. On most things you go for length of experience and managing to stay in business (i.e. not developing such a bad rep or warranty history that you get driven out of business)

pliptrot · May 2007

Good points made above about inspection. Monty dog, those guys who design bits for fighter aircraft will no doubt be happy to concur that those bits are regularly, meticulously inspected -using techniques not accessible to cyclists- and frequently replaced. They can tell you this even if they didn't go to Cambridge.

I also suggest that the life of a cycle frame can be every bit as tough as that of any other machine or structural part. There are not many structures out there capable of supporting 100 times their weight in dynamic conditions.

hamstercp · May 2007

Let's also remember that fighter aircraft are quite dangerous to fly. Safe ones are slow and unmanoeuvreable and get shot down...

The key issue is the experience of the designers and production people. On all things there is a learning curve. Fashion also encourages bike makers to cut corners (e.g. making things too light.) In the world of racing yachts where carbon happened about 10-15 years ago a lot of masts broke, some hulls snapped in two and a fair few keels fell off until the stresses and design rules were understood. The same is happening with bikes at present. There are good and bad, some know what they are doing and some don't. Many carbon forks actually have aluminium crowns. Buy with care.

(and yes I am an Engineering Graduate, sorry!)

"It must be true, I saw it on the Internet!"

bike_the_planet · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Monty Dog

You'll also find a few other people around here who are also engineering graduates and have pretty extensive experience of materials and composites, particularly in the aerospace and related industries used in far more demanding applications than bike frames. Professionally speaking, being a Cambridge engineering graduate and having reached the heady heights of CTC Technical Officer doesn't count for much in my book, but within 20 feet of me, I have about 10 guys who design bits for fighter planes - I think I know whose professional experience I'd rely on.
<hr height="1" noshade id="quote"></blockquote id="quote">
'
Heady heights' of a technical officer? Oh dear...is this one of those "my job's more important than yours" postings...I can just see one of those "degrees at dawn" slug-outs coming on...ha ha ha...

I can't speak for Mr Juden, but I dare say that he does what he does because he enjoys doing it, not to impress people...

How often is your plane inspected, Monty Dog? Every 6 hours flying time? Every sortie? What sort of inspection do they do every 100 hours on some of those parts that see high stresses?

It doesn't matter whether it's used in a fighter jet or a bike fork, any carbon fibre part who's efficacy you rely on, needs to be inspected regularly for obvious signs of failure.

Fact: the failure mode of carbon fibre and certain other composites is catastrophic. It's simply not a ductile material. Any book on material science will tell you that.

Does it mean it shouldn't be used on bikes? Of course not. What it means is that, if you want to rely on that part for your safety (and most cyclists descending a hill at 80kph plus probably do) then it needs to be used with a bit of care and regularly checked over.

And yes, the aerospace industry did go through alot of angst about preventative maintenance on carbon before finally introducing it. Simply because many early signs of degradation just ain't obvious.

Thanks for your amusing post - I enjoyed it!

monty_dogcp · June 2007

I'm just comparing the fact that people on here are prepared to put the 'technical officer of the CTC' on a pedestal and continue to propoagate this sort of 'forum bull' with a complete lack of informed judgement. I'm not trying to enter into some form of p*ssing contest about who or what I know - no bike frame material can be guranteed 100% safe but some of the things people say on here about carbon being brittle, catastrophic failure etc is just fear-mongering - as others have pointed out, I've seen far more broken steel and aluminium bikes due to corrosion, fatigue failure and cracking than carbon ones. Crash-damage excepted, I'm perfectly happy riding my carbon framed bike knowing its limitations, as much as I am riding the 2 titanium, 3 steel, or 1 aluminium framed bikes I have at home...

bike_the_planet · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Monty Dog

I've seen far more broken steel and aluminium bikes due to corrosion, fatigue failure and cracking than carbon ones.
<hr height="1" noshade id="quote"></blockquote id="quote">

The reason that you will see more fatigues failure in aluminium and steel than carbon, is that carbon doesn't suffer from fatigue failure. Fatigue failure is only a property of certain ferrous and non-ferrous metals due to cyclic stresses at a level below the yield point.

Catastrophic failure is not scaremongering. Catastrophic failure is a technical term referring to the failure mode of materials that don't have an effective yield point. In other words, they don't deform in any way before they snap, and therefore don't give any warning.

I believe that if you looked through my previous post carefully, you would see that I haven't suggested that anyone shouldn't be happy riding carbon fibre or composite bikes.

All I suggested was that, untlike steel and ti, they require regular checks to ensure that there are no obvious tell-tale signs of degradation, such as discolouration or wear exposing the fibre weave.

I do hope you continue to enjoy riding your carbon fibre bicycle.

And do have a nice day, old chap.

Tom Butcher · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote"> In the world of racing yachts where carbon happened about 10-15 years ago a lot of masts broke, some hulls snapped in two and a fair few keels fell off until the stresses and design rules were understood. The same is happening with bikes at present. <hr height="1" noshade id="quote"></blockquote id="quote">

What - lots of carbon forks, frames, stems breaking? I haven't heard of them, I'm not saying it hasn't happened but it certainly isn't happening very much.

Warning about well known bike shop removed at request of moderators.

Unknown · June 2007

"On most things you go for length of experience and managing to stay in business (i.e. not developing such a bad rep or warranty history that you get driven out of business)"

Giant or Merida then!

d.j.
"Like a true nature's child,
We were born,
Born to drink mild"

Will1985 · June 2007

I've got enough broken hockey sticks made of carbon or kevlar to make 5 or 6 frames. In any sport where carbon is used there is a "usual" limit of usage of the item such as the amount of wind strength a mast can hold with a full sail or the strength used to hit a hockey ball, but all a frame does is hold the components together. So, Tiralongo's crash in the Giro yesterday demonstrates what happens when carbon is subjected to unusual forces outside of the normal range.
Of course, the same idea can be used for any material as we saw when Hincapie's aluminium steerer snapped in the 2006 Paris-Roubaix - cue the "steel is real" brigade.

4candles · June 2007

Funny thread... keep it coming.

Carbon frame reliability

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