Carbon frame life cycle

If it were me, I'd drift towards ti or very good steel for a 'forever' bike.

That said, as there are many aspects of bike design in a state of flux (brakes, cable routing, hub spacing and dropouts, headsets, BB shells off the top of me 'ead) then maybe just buy the one you like the most and enjoy it.

All things considered, a high quality steel frame will outlast anything else on the market. The weight penalty (at the high end mind) will be less than 1kg and you will benefit from skinny frame aerodynamics, I'd love to speak with the engineers at Madison and Genesis http://www.genesisbikes.co.uk/bikes/frames/road/volare-953-di2

But, back to your question… so long as you don't scratch into the strength layers or break it I'd expect a CF frame to last as long as epoxy does, ie about 20 years. Boeing's biggest plane uses a CF frame and they are not made to be disposed of after 5 years.

I seem to remember that, when carbon fibre frames first appeared on our Christmas lists, one manufacturer's testing laboratory released a video of different forks being stress tested on a powerful machine that repeatedly flexed the legs.

The engineer reckoned an aluminium fork might tolerate this torture for a few hours, a steel design for a whole day and the carbon equivalent would still be in one piece in a year's time. I was mightily impressed by this claim and have no reason to doubt its veracity.

I should say that it didn't affect my judgement of aesthetics. I still don't like the look of those huge, ungainly tubes and have never bought a carbon bike. I have succumbed to the lure of composite forks but that's as far as this old man is prepared to go.

Certain manufacturers stick original owner lifetime warranty on their carbon frames so those must have some confidence in them.

Does this mean I should really consider getting a titanium bike instead?

structural integrity will last about 5 years (the same as aluminium)

this isnt saying after 5 years the bike wont last, but more that the quality will have dropped as will have the structural properties.

its like anything, it depends how its looked after.

I believe if dropped or crashed, the big teams crush them, I didn't put that in!

But yes, fair summary and bear in mind, that part of my post might be total shite, as it's just what I was told.

My post summary is actually, they 'might' lose stiffness with use and thus lose their 'edge' I don't recall any stories of frames failing in use....unlike forks and rims, which in reality, were probably damaged.

People still ride around on 20 year old C40s...

So, lets summarise Flying Scot's reply: If you are a top pro riding the sponsors latest advert, 6 months/1 season of hammering over cobbles and poor road surfaces then replace it with their latest "must have" model. Frame then handed down to a junior team to get hammered/crashed then handed down again to a feeder team. Manufacturers seem happy with this and confident that something with their name on will take this level of abuse. No life issues there then. A former pro uses his for 2 summers and 3 winters (5 years in total) then he is still confident enough to sell it on for someone else to use and buy another carbon frame. So no life issues there either.
I think that this is a good advert for carbon frames and unless you are really hammering them then I don't think you have any life issues with decent modern carbon frames. Does that sound fair?

Firstly, I'm not a composite engineer, but a friend who is a former pro ( not a very good one) runs carbon frames for 2 summers, then relegates them to 3 winters, then sells them.

That's his take on it.

I also heard, though it may be here say, that the pro teams race bikes get used for 6 months tops, then get made the spares for 6 months, then go to the junior team for a year, then get handed to feeder riders for training and don't get raced again.

I think there is good evidence that the stiffness isn't everlasting, but I also know guys on 10 year old stuff that hasn't fell apart from beneath them.

I do recall Ferrari being very careful about painting carbon and not exposing the weave until about 5 years ago, they were worried about UV.

My main bike was made of air hardening cro-mo ....61 years ago. Needs painted every 12 years or so though.