I’ve broken a few, 7, (5 road frames , 1 cross frame , 1 FS MTB) plus my current Giant XTC has a very wicked looking paint crack at the seat tube / top tube junction. No creaking at the moment but it’s not pretty.

Good to hear about Giant’s warranty. Got stuffed on my Colnago EPS as it was in it’s 3rd year and Colnago said £440 to fix please.

Aren’t carbon frames generally lighter than steel,alu and titanium ones?
If so and if there was an issue with their longevity and/or strength ,then couldn’t they be over engineered to improve this whilst retaining the positive characteristics/feel of carbon and still be competetive weight wise?
Either it isn’t really necessary or it’s an industry ploy to have carbon bikes fall apart.

nick1962 – Member

If so and if there was an issue with their longevity and/or strength ,then couldn’t they be over engineered to improve this whilst retaining the positive characteristics/feel of carbon and still be competetive weight wise?

They can- look at, frinstance, the Carbon 456 or a Mojo HD, strong like ox. But road bikes and racy XC bikes tend to go more for lightness.

Isn’t the Carbon 456 still a kilo lighter than the steel one?
Plenty of scope still for making it stronger if needed…but not really necessary?

I’ve broken a few, 7, (5 road frames , 1 cross frame , 1 FS MTB)

How, what?

Broke a steel crosser, but it was 35 years old and I was using it on trails.

Looks like the original poster has been scared off…

i am no expert but what I do know is that the term ‘carbon frame’ can be misleading as it suggests that any one carbon frame is the same as any other… clearly it is not as there are many different lay ups, resins and bonding methods used so each frame will have different qualities and failings.

From my experience the carbon frames I own and have owned and sold have been extremely strong with high impact resistance. That is not to say that I haven’t experienced failures but the carbon frames have compare well against steel and very favourably against ally.

In short…. buy the frame that suits your needs based on size, geometry and intended use…. frame material should not really influence your decision as much as the above.

And whatever you do enjoy it rather than worry about it…

Who has ever seen a carbon frame break due to fatigue?

I once saw a Trek Carbon Y22 snap spectacularly – the whole seat post arm snapped off. It frightened me a lot because I was 3 feet away on the exact same bike!

No idea of whether it was fatigue though…

Mine was later stolen! 🙁

There’s an interview in this week’s comic with Trek’s head carbon guy and his point is carbon fibre doesn’t have a fatigue life however if you do the resin etc. wrong then you can introduce issues that way and shorten it’s life. There’s also carbon fibre used in aerospace/defence that gets a lot more abuse than bikes and I don’t see horror stories about planes dropping out of the sky due to carbon failure.
As for crashing – yeah if you buy a bike made from thick steel tubing it’s going to be more impact resistant but who wants to ride around on a something weighing the same as a small car? The common alternative is aluminium and give the walls of a lot of alu tubing I don’t get why someone would argue it holds up better in a crash.

But over time, they go soft/delaminate, you can get water/salt incursion between layers and/or through the resin. the resin might not be uv stable and it certainly wont be corrosion proof and will degrade with water/salt sunlight exposure!

How can a material that’s impregnated with resin be susceptible to water ingress? And why would salt be a problem to a inert substance like carbon?

Sounds to me like you’re taking your limited knowledge of alloy/steel bikes, a few urban myths, a little supposition and basing your arguments on that!

The head carbon guy from Trek is interviews in CW this week, you might want to read it. He has developed carbon for the US military for 30 years. His opinion is that a carbon frame will NOT degrade at all unless it suffers significant impact damage.

There is two type of carbon bikes.
Scott and the others. I see on a “regular” basis the same 1998 scott endorphin in the workshop of my LBS. Frame is still going strong, in spite of regular riding in the southern Alps.

How can a material that’s impregnated with resin be susceptible to water ingress?

Easy.

If you overload a piece of carbon it can delaminate, which will allow water in. Whether this will happen on a bike is another thing.
Salt is a problem when mixed with water because it’s a conductive fluid, and can cause galvanic corrosion if precautions haven’t been taken to prevent it.

I better clarify my post.

Out of the 7 frames, 4 were carbon, 2 aluminium, and the Colnago whilst carbon, failed on the drive side seat stay aluminium dropout.

1) Isaac Force – Chain stay failure
2) Isaac Force – Chain stay failure
3) Isaac Sonic – Seat tube
4) Trek Madone 5.5 – BB shell
5) Kinesis Evo 2 – Chain stay failure (aluminium)
6) Colnago Extreme Power – Seat stay, aluminium rear drop out snapped
7) Trek Top Fuel 9 (2008) – Seat tube crack

The Colnago was the only one that had a catastrophic failure.

Pfft, no one’s mentioned osmosis yet? 😉

I reckon the broader scale use of heli-tape will probably help a little for all frame materials. If the external layer of paint/lacquer/clear coat is maintained then the horrible outside world can’t penetrate the frame material. Unless you crash. But then again any crash can total a frame.

BMX frames are super tough and fail all of the time, anecdotal evidence only refers to the way that individual used their bike. Then again catastrophic accidents and MTB are quite good friends.

I’ve wondered how much a sacrificial layer of kevlar or just support strips would add to a carbon frame (when laying up, not after manufacture)?

Treks head carbon guy never invented treks methods this is journalism at it’s best yet again

We had a Spark frame we had to destroy (aluminium shock mount cracked). So I hit it with a 1lb ball-pin hammer. Hard. It was fine, repeatedly. After about 10 blows I chipped the lacquer.

Then sawed it in half along it’s length, quite interesting.

One blow would’ve made a big ol’ dent in an alu frame!

Isn’t the Carbon 456 still a kilo lighter than the steel one?
Plenty of scope still for making it stronger if needed…but not really necessary?

They are massively over-built, I believe. I weighed my frame at exactly 1500g before I built it (16in) and how light is it possible to build a carbon MTB frame these days??? Sub 1000g easily – 900g????

So in my book that’s 50% extra material purely for strength.

Had my carbon seat post snap sending me across the road in front of car. Totally unscientific but put me off carbon for life.

As others have said not all carbon is equal, there are differences in modulus and layup techniques. So it’s hard to generalise. As also said above the big issue with carbon is it’s relative inability to withstand impacts, particularly “sharp ones”, for example the type you would get by hitting a sharp angled rock.

For a road bike or an XC style bike carbon is an obvious choice, IMO for a bike which is going to take more abuse I personally would steer clear.

As an aside, with a little skill and the correct facilities (ie a curing oven) carbon is pretty repairable.

how light is it possible to build a carbon MTB frame these days??? Sub 1000g easily – 900g????

Scale 899 is guaranteed under 900g.

As also said above the big issue with carbon a bike frame is it’s relative inability to withstand impacts, particularly “sharp ones”, for example the type you would get by hitting a sharp angled rock.

FTFY – thin walled alu tubing isn’t known for it’s sharp-impact resistance 🙂

oooops

Njee, that was almost funny once a few years ago… 🙄

It’s a valid point though – not aiming to be funny. People say “carbon’s inappropriate, because if you stuff it onto a pointy rock at speed you may crack it”. C’mon FFS you really think an aluminium frame will survive that? It’s bollocks.

is it that time of month again for the Carbon debate…it comes round quick.

What Njee says

Any frame can break/rust “degrade” etc
The only thing that concerns me with a carbon fibre frame is that it wont dent on impact unlike metal so it may/is harder to tell/judge/assess any effect of the impact.

It’s quite comical really, listening to some of the bollocks people “assume” and the urban myths. I particularly liked the “I seem to remember someone saying they degrade 10% after 30 years”… 😀

Even the head honcho of carbon production at Trek plays his cards close to his chest, so what are the chances of a bunch of IT nerds that ride bikes once a week being able to speak with any authority??

As for carbon being “easy to repair if you’ve got a curing oven”, good luck with that! The Trek guy very eloquently explains exactly why carbon frames shouldn’t be repaired unless under exceptional circumstances.

Frame tubes are designed to flex in certain directions. If you build up an area with a patch, you affect the tube’s ability to flex in the correct way, thus putting excessive loads on the unrepaired areas.

Imagine mending a fishing rod in this way – you’d end up with 2 VERY vulnerable and highly stressed areas on either side of the patch.

As for carbon being particularly vulnerable to sharp impacts? Nonsense. Carbon is THE BEST material to cope with sharp impacts, y’know, like people firing bullets at planes, and bullet proof vests…

It might damage, but it’s far less likely to suffer catastrophic failure than alluminium or steel. Fact. ;o)

firing bullets at carbon panels?

Frame warranty is usually about manufacturing defects. Ive been shopping for a new bike recently and many have been carbon and i have been surprused how few years warranty they come with. It’s seem about 2 years which is pretty crap.

Somewhere in the admin office there must be a complex mathematic equation that the big bike companies have, something that includes:

frame material + test lab stats – history of customer returns = we can only offer 2 years before the profitability drops below the desired amount.

My 1992 Giant carbon road frame died last year. A crack appeared in one of the aluminium lugs…

compositepro – Member

firing bullets at carbon panels?

I believe they use bullets in the theatre of war. And whilst I can’t be certain, I would expect some of those bullets to hit the carbon fibre sections of military aircraft and vehicles.

And again, I’m guessing, but they’d be pretty well f**ked if they failed catastrophically after one bullet.

But hey, I’m no expert.

phew… thanks for the replies….

the original post was just to put my mind at rest should i splash out on a new parlee or cervelo frame to replace my litespeed vortex, but seeing as the frame is still in tip top condition i’m hoping i’ll not need to… just vanity / buying urge…..

did see a nice vortex on fleabay with a cracking (!) BB crack from weld into tubes…oh i hate pics like that 🙁

now then… you are buying a carbon road frame, you have 2K to spend, what would you go for / or avoid???

Giant have a lifetime warranty. I’m on my third

No they don’t, it’s five years for all Giant frames, regardless of frame material.
I still regularly service 90’s Giant CFR team road bike, think it’s now on it’s 4th groupset & still rides fine with no sign of dying any time soon.

I believe they use bullets in the theatre of war. And whilst I can’t be certain, I would expect some of those bullets to hit the carbon fibre sections of military aircraft and vehicles.

And again, I’m guessing, but they’d be pretty well f**ked if they failed catastrophically after one bullet.

I suspect some of those bullets might also hit aluminium sections of said aircraft, and you’d be equally f**ked if those failed catastrophically.

Where exactly is your evidence for:

Carbon is THE BEST material to cope with sharp impacts, y’know, like people firing bullets at planes, and bullet proof vests…

It might damage, but it’s far less likely to suffer catastrophic failure than alluminium or steel. Fact

If carbon is crap, why do some companies give lifetime warrantees?

aplonker – Member

Where exactly is your evidence for:

Carbon is THE BEST material to cope with sharp impacts, y’know, like people firing bullets at planes, and bullet proof vests…

It might damage, but it’s far less likely to suffer catastrophic failure than alluminium or steel. Fact

Erm… The fact that it’s the favoured material for making things that need to withstand sharp impacts? 🙄

The fact that it’s the favoured material for making things that need to withstand sharp impacts?

You mean like aeroplanes and bullet proof vests?

You don’t think there might be some other design requirements for planes?

Maybe you should also check what bullet proof vests are made from.

You’d think alu and steel frames or bits never fail to hear some people on here.

I imagine most carbon frames will go aesthetically & technologically obsolete, before they become physically obsolete.

And then you can’t recycle it.

aknobhead – Member
You don’t think there might be some other design requirements for planes?

Possibly, like low weight, structural strength, ease of moulding/manufacture, flexibility, the ability to control flex/rigidity… Absolutely nothing like bikes, eh? What point are you so desperate to make but so unable to put across?

What point are you so desperate to make but I’m so unable to put across? understand

FTFY <sigh>

That just because they make planes out of carbon composite and planes have to withstand impact, it doesn’t follow that carbon composite is the best thing for withstanding impact.

Oh and <applause> for the ad-hom

So which material gives the best balance of light weight, impact resistance and flexibility of manufacture?

Actually, don’t tell us, go on Dragon’s f***ing Den, you’ll make a fortune! 🙄