Thinking about my next bike and the prospect of a reasonably priced On-One 456 carbon frame has got me thinking about a material I have never had much interest in.

I get the general impression that carbon is strong and light. What I don’t understand is does it stay this way once you have cocked up on a descent and bounced it off a few pointy rocks.

Any pointers to relevant articles or well informed opinions from long-term carbon frame owners appreciated.

does it stay this way once you have cocked up on a descent and bounced it off a few pointy rocks.

Depends how hard…

Much the same as steel, ti or aluminium which also don't like pointy rocks.

wiki

I've a carbon road bike and was amazed at the difference in ride quality and handling with it. Most of the objections seem founded around impact resiliance, however drop any bike hard enough and it will kill it.

not an owner, but interested reader! From people's/ owners' comments I've seen on here, carbon will fail if you bang it off some rocks, but no more than a similar ally race frame would if similarly banged off similar rocks.

Just like they ^ said.

if you look at modern crash tests on carbon they actually fair better and are far easier to repair and cheaper to do so!

main difference is you will be able to tell what damage you have done to materials other than carbon. Metals will deform or split to show the degree of damage done after a big off …with carbon it is far harder/impossible to tell just how much damage has been done by a visual inspection. OK for road but not MTB + Ok with some components but not rear mech.
EDIT; Yeti carbon rear stays for example

I too have a carbon road bike (got it at the end of the summer). I noticed no difference in it at all (over my old ally frame). They both feel nice to ride and handle well. So…. i was a bit underwhelmed at first. It wasn't until after a ride with some mates that they commented on the acceleration that I realised something was different. Where I used to wind up to a sprint they all said that on the carbon bike, once I decided to go, it accelerated like a rocket, as opposed to a gradual increase in speed on the ally bike.

Impact resistance… yes that does worry me.

This again…

I'll say the same thing I always do, I had a 6 year old carbon fibre DH bike. What killed it eventually? An aluminium insert cracking. Carbon was fine.

Also this is worth a watch:

be sure to watch through till he gets the alu one out…

Talk to On One about it. I'd imagine the frame's probably undergone fairly rigorous testing.

don't trust it. Tis the devils work. Witchcraft I tells ye, witchcraft!

Nice link IA, wonder why those frames are missing their bb shells?

They're probably warranty returns, cutting out the BB shells makes sure they don't find their way back out to the public.

I used to do a lot of work doing impact, penetration and tear tests on Carbon Composite Helmets. The failure mechanisms of carbon just simply splitting in half when smacked on a rock are myths.

I would have no worries about selecting a Carbon Composite frame over a metal one. From the research I have done though i now replace my helmet EVERY time it has an impact, no matter how light.

Yes the link is really impressive. Cheers

Ah, that makes sense.

I've got a carbon trek madone, a blur lt carbon, and had a cannondale taurine carbon, along with numerous carbon bars, seatposts, cranks, brake levers, saddles, mech cages, and helmets. Never had a sniff of a problem in anything, yet i have broken plenty of aluminium stuff. High quality carbon products will outperform aluminium and steel alloy parts in many ways. True, a crash can cause invisible damage in the 3d material, but i have never had need to worry, and it's not through not trying hard enough! Many manafacturers have some sort of back-up for crash damaged parts just in case. It's worth pointing out, that there are a lot of crap "generic" carbon products out there, and i'd always be happier getting something from an established carbon manafacturer.

http://www.bustedcarbon.com/ is always an interesting read a mixture of random failures vs crash damage (including no carbon wednesdays!).

I'm not pro or anti-carbon. I don't necessarily think it's the 'holy grail' material bike manufacturers seem to promote it as for some applications but when invovled in a crash it will break just the same as alloy/steel/ti etc. depending on the forces involved.

Is it easier/cheaper to repair or replace a steel frame than a carbon one though?

That bust carbon site is so gash. I wonder how much bigger (and no less dull for that) a one dedicated to metal bike components breaking randomly, would be?

Carbon is actually very damage tolerant – that's why it is often used in regions where impact damage is expected in aerospace and defense.

Metals can yield which is bad if subsequent loading is seen (hence why a dented frame is usually considered as a write-off). For an equivalent impact load, composites will suffer more superficial damage with little effect to the material properties of the remaining material. that is one of the biggest benefits of composite (carbon fibre) vs. homogeneous (metalic) materials in structural applications.

Carbon fibre is also more tolerant to fatigue. Aluminium doesn't have an endurance limit – that is, for any load, aluminium will eventually fail.

Note though that the above is assuming that the frame is designed correctly, however this applies to ANY product whatever the material.

Have you ever tried tearing a J-Cloth? well try tearing one coated in varnish coz that's what carbon fibre is.

It depends how you make it- for instance, some people freak out when they see a scrape in a carbon part, but generally the top layer is non-structural for exactly this reason. You can make carbon fibre which is superlight and very damage intolerant, but anyone who knows what they're doing with mountain bike parts won't be doing that.

I think a lot of people have had bad experiences with carbon but then, a lot of carbon parts in the past were pretty rubbish. Some still are. But if you cracked an aluminium frame you wouldn't say "Never again, aluminium just isn't suitable for bikes!"

It's a myth that the frame/parts designers are trying their best to overcome, all this stuff about carbon shattering/not being damage resistant etc. Most of the big frame manufacturers now are totally sorted on carbon, they've got 10 years experience behind them.

Easton warranty their carbon bars for life; their aluminium bars have a 5 year warranty…

Thanks one and all, pretty reassuring stuff.

TBH I still see old Giant Cadex carbon frames getting raced, on the other hand I've seen some components break but that's always been down to ham/spanner fists.

I must admit that I'm wary of some of this bargain stuff direct from Hong Kong, for some reason the fact it's cheap is off putting?

I've got a bargain carbon hardtail from Hong Kong on its way, lets see if it lasts…

For £160 I'm not that fussed frankly.