Carbon frame life

[neilob]

I have a dilemma.....my Colnago C40 is 20 years old. It has never been dropped or crashed. I replaced the forks two years ago with genuine Colnago forks because I was concerned about safety although there were no specific issues. It looks stunning having been renovated by Atlantic Boulevard and is in the lovely art decor finish so popular amongst Colnago fans. It continues to ride well, fits me perfectly, and draws admiring glances wherever it is parked. So my dilemma is should I be riding it hard still? Or should I hang it on the wall as a piece of art and buy something new to replace it? Fundamentally I am just concerned that few carbon frames are as old as mine even if it is built by real craftsmen.

[Spinners]

Definitely continue to ride and enjoy it!

[tim-b]

Hi
No dilemma here...
The article is less specific than its title suggests
...or here
Regards
tim-b

[reohn2]

Hi
No dilemma here...
The article is less specific than its title suggests
...or here
Regards
tim-b

Thanks for those to links,pretty much what I've thought and read myself about bikes made from CF the good ones are good but the achilles heel is bonding,mostly to other materials,aluminium usually,and impact damage,both of which kill CF frames and forks and which metal frames are able to withstand much better.

I don't feel qualified to advise the OP about his bike but IMHO if it were mine and I'd owned it from new and knew it's history,I'd keep riding it and inspect it regularly,but given the fork's been replaced recently,which is the most suspect component for catastrophic failure,I'd feel confident about it.

[Gattonero]

Corrosion between the alluminium parts and carbon is the killer, inspect carefully and if the bike have always been well kept and nver exposed to high temperatures (I assume the respray was done properly) then it will be fine, the fibers themselves have long lifespan when they are good quality

[reohn2]

Corrosion between the alluminium parts and carbon is the killer, inspect carefully and if the bike have always been well kept and nver exposed to high temperatures (I assume the respray was done properly) then it will be fine, the fibers themselves have long lifespan when they are good quality

In my limited exposure to CF bikes,I've seen two front forks,alu steerers/crowns(the standard CF/alu steerer fork)which have failed in that a line/crack was discernible around the fork leg,about 30mm down from the headset,the fork leg in one case was able to be pulled off,both bikes were still being ridden when the fault was found and thankfully for their owners didn't fail catastrophically.
I think it's extremes of temperatures that cause such problems,with expansion contraction of the two materials at different rates which cause the failure to start,followed by water/salt ingress accelerating the process,once a tiny crack between the two materials has started.
This only my own opinion.

My other reservation about CF frames is the BB area where an alu BB shell is bonded into frame in a high stress area which is also subject to the worst of water/salt road dirt and grit,especially on bikes with m/guards.
I know later bikes are being fitted with press fit BB's directly into CF BB shells but the very thought of a press fit system is enough to make me shiver ,it an't good engineering IMHO.

[Gattonero]

The problem is not press-fit or bonding, but HOW it is done.

All the times you hear about problems, is poor machining and poor fitting. Things like BB shells that are suposed to be 46.0 and are actually 46.2, bearings installed without one gram of grease, etcetc.

[reohn2]

The problem is not press-fit or bonding, but HOW it is done.

All the times you hear about problems, is poor machining and poor fitting. Things like BB shells that are suposed to be 46.0 and are actually 46.2, bearings installed without one gram of grease, etcetc.

So a combination of poor manufacture and poor assembly?
The first shouldn't happen end of.
The second is poor training and or working practice by mechanics.
Or a combination of the two?
Either way the tolerances are tight,and on machines and workshops working down to a price rather than upto a standard results can be really bad for the customer.
It seems to me bicycle manufacture and maintenance is becoming so technical as become almost ridiculous in some instances,it's the same with groupsets and the differences between them with any cross use and integration being deliberately manufactured out,
It's very cynical of those manufacturers for little gain(other than profit)except at high pro racing standards.

The crazy 11 and 12 speed rear ends and very compact double with an absence from the catalogues and almost outlawing of the triple chainset being a classic example.
Anyway I'm rambling,so I'll leave it there.

[Gattonero]

[....
Either way the tolerances are tight,and on machines and workshops working down to a price rather than upto a standard results can be really bad for the customer.....

Press-fits are done to speed up assembly at the factory. And most of the bikes are disposable, being made obsolete by a new (?) model after one year.
That's what most people wants, you know, back in the day you would spend a lot more of the equivalent of a good month's wage in a good bike that would last long, and spend money in repairing/maintaining things.
Now everything has to be cheap, we cry when we hear a frame costs more than £500, a mid-range groupset is more than £300. Those are things that require more good materials and less labour involved; but in today's economy is the other way round: cheap parts to be disposed so to avoid labour cost.

Most carbon frames are a perfect example of this

[reohn2]

[....
Either way the tolerances are tight,and on machines and workshops working down to a price rather than upto a standard results can be really bad for the customer.....

Press-fits are done to speed up assembly at the factory. And most of the bikes are disposable, being made obsolete by a new (?) model after one year.
That's what most people wants, you know, back in the day you would spend a lot more of the equivalent of a good month's wage in a good bike that would last long, and spend money in repairing/maintaining things.
Now everything has to be cheap, we cry when we hear a frame costs more than £500, a mid-range groupset is more than £300. Those are things that require more good materials and less labour involved; but in today's economy is the other way round: cheap parts to be disposed so to avoid labour cost.

Most carbon frames are a perfect example of this

That seems to be the problem I agree,and last years colour is out of time and out of date.
Vanity,vanity all is vanity......

[colin54]

This video of a carbon frame repairer/inspector may be of interest, he uses ultrasound to scan older frames.

Excellent interesting video once it gets going.

https://www.youtube.com/watch?v=-qsLYlVWkbQ

[neilob]

Thanks everyone for these well considered replies. The links were very interesting and give confidence that the frame will be fine. It's just that people tell me I am mad to ride a 21 yr old carbon bike albeit with new forks. Of course they dont have evidence, just prejudice! So it looks like I may get another season out of it.

[Mick F]

............. it looks like I may get another season out of it.

......... or more.

[Brucey]

well to add to this discussion....

it is as well to remember that the frameset was (presumably) intended to be ridden for one season of pro racing (more or less) by a rider weighing about 70kg. Pro riders typically put out an average of about 200W or so, but often pedal smoother/faster than amateur riders, so the stresses the frame sees may be less than a clumsier amateur rider with a slow cadence, even if the power output is less with an amateur.

If a pure race frameset was definitely going to last two or more seasons, it would arguably have been considered overbuilt for the task in hand. The original warranty duration may be a guide to its expected life.

Now some (including one of this nation's more noted cycle designers, with whom I was chatting earlier on today) will say 'ah but CF doesn't fatigue'. And there is some evidence to support this notion; however it is mostly based on laboratory test coupons, which have perfect layup and uniaxial stresses. The reality is that anyplace you have 3D stresses and the possibility of imperfect layup, things are different, and the plies may not share the load, delamination may start to occur, the bonding of sections to one another may be suspect, and so....

Most of the responses in the Zinn link were vaguely optimistic but then they would be, wouldn't they?

The bloke from Deda was a little more direct and circumspect; he reckoned that an epoxied joint would be good for 2000 hours loaded use, provided the weather (sun and rain) wasn't in play. The matrix in many CF parts is basically epoxy too; not all grades resist UV exposure very well.

Gattonero is quite right about the ghastly effect of our winter weather on bonded joints; I am told that some manufacturers have applied a layer of glass fibre in the joint to help prevent galvanic action between CF and aluminium, but this won't prevent the Al part from turning into dust, and no bonding sticks to dust....

So.... nothing lasts for ever. When taking a view on this sort of thing it is perhaps as well to examine the relationships in terms of risk and consequences.

I'd agree that changing out an old CF fork is a good idea; even if the risk of (undetected beforehand) failure is low, its consequences are not. For the rest of the frame, it is a different matter; cracks in CF are not always easy to see and they can propagate rather quickly from 'small enough to miss' to 'oh dear the frame is broken', all without much of an intermediate 'there must be something wrong because the bicycle is kind of floppy' stage.

Most people who have broken carbon frames either picked up a crack that was visible before it propagated to failure, or had the part break in service with 'no warning'. If just one frame joint or part fails in service it isn't guaranteed that you will have a nasty accident, but then again the converse isn't assured either.

So if you do carry on riding it I'd suggest that regular inspections are a good idea. I'd also ask the question 'what will cause you to retire the frame'...? If you don't inspect the frame often enough and you carry on riding it, it is very likely to fail in use with you on it, eventually.

cheers

[reohn2]

Thanks everyone for these well considered replies. The links were very interesting and give confidence that the frame will be fine. It's just that people tell me I am mad to ride a 21 yr old carbon bike albeit with new forks. Of course they dont have evidence, just prejudice! So it looks like I may get another season out of it.

I've had people tell me I'm mad to ride 35 and 40mm tyres claiming they'll be like riding in treacle,though they've never ridden them themselves