Carbon frame life cycle

My understanding is that
My understanding is that different materials behave differently to load.

For instance aluminium is compromised with every bend, twist, vibration it is asked to absorb. Over time the material degrades and at some point, no matter what you do, it is going to fail.

Steel has a definite yield point. Below that yield point it can suck up as bending, twisting/vibration almost indefinitely. Above that yield point, then the material ages in the same way as aluminium.

Titanium is like steel, although the yield point is considerably higher…. so it can take more extreme bending etc. The challenge with this is that it also makes for a bendier frame, so manufacturers mix in alloys/treat the material in such a way to stiffen it, which also lowers the respective yield point. So.. you can have a ti frame for life, but it rides like poop, or one that rides well, but has a similar life expectancy to steel.

Carbon, as I understand it is a yes/no material. It’ll bend, twist, vibrate within a range indefinitely. Push it beyond its limit and it will fail spectacularly, and rapidly. The challenge with carbon is as mentioned, blunt impacts can compromise the material and right now we are still in the realms of developed understanding of the long term degradation of epoxies.
The great thing about carbon is that it is so un-precious its untrue. Punch a big hole in your frame… as long as you fix it, its no bother at all.
Its certainly not the super fragile material some make it out to be.

Neil753 wrote:There’s always

Neil753 wrote:

There’s always going to be opposing views on carbon, but you you’d have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders. We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

You certainly don’t have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it’s sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

You’d have to be pretty isolated not to have heard the same about metal frames.

It has been known for cars to fail and hurt people, by your metric you’d better not drive, get on a plane, push a supermarket trolley………….

Your point about responsibility to other road users linked to frame choice is weak at best and as for destroying a £2500 frame after “any impact” is stupidity at it’s finest ( I suspect getting it checked by an official dealer might be a better call?)

Carbon, in some cases, is easier and more effective to repair than metal and will, if correctly looked after, last just as long if not longer (it doesn’t corrode you see).

Yes there are shitty Chinese fake Pinarello’s out there but you’d be a fool to buy one in the first place, if you can’t afford a genuine bike set your sights a bit lower or save a bit harder.

I understand you’re a fan of steel, I’m a fan of all bikes and great workmanship, but don’t do another product down because you don’t fancy or can’t afford it.

Fair enough I have a classic
Fair enough 😉 I have a classic steel frame too (in need of restoration, but it was my trusty steed for many years, and has taken much punishment). It’s a joy to ride in many ways, and I fully plan to do some touring on it once it’s been sorted out. But carbon isn’t something to be afraid of.

Neil753 wrote:There’s always

Neil753 wrote:

There’s always going to be opposing views on carbon, but you you’d have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders.

And I’ve heard the same of Aluminium, and it’s probably happened with cheap steel too, I seem to remember a story a couple of weeks back of someone trying to sue Halfords when his steerer broke. It happens to all materials.

Neil753 wrote:

We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

Rather off the point, your frame material really doesn’t factor into responsibility towards other road users. I pay for the emergency services and the NHS (and for my insurance for that matter) and as such I feel quite entitled to use them if I have an accident. Carbon isn’t just about weight saving, you can get superior stiffness, aerodynamics, comfort, looks. What is clear about it? Why would your priorities automatically be shared by anyone?

Neil753 wrote:

You certainly don’t have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it’s sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

Brought to you by (insert bike manufacturer here). You could say that about ANY frame material. You can have carbon repaired quite happily, to a good standard. As with any second hand purchase, check it over carefully.

It’s stronger, more durable and lighter than steel. Live with it.

There’s always going to be
There’s always going to be opposing views on carbon, but you you’d have to be pretty isolated not to have heard, read or seen examples of carbon frames and components which have failed, quite often without any prior warning, sometimes at high speed, and sometimes causing injury to other riders. We all have a responsibilty towards other road users, and indeed towards the resources of the emergency services and the NHS, and clearly far more important than a small weight saving.

You certainly don’t have to be an engineer, armchair or otherwise, to conclude that if you really want to ride carbon then it’s sensible (and responsible) to only buy from a well known source, destroy any frame/component immediately after suffering any impact, never lend your bike to anyone, and never EVER buy second hand.

Carbon should last as long as
Carbon should last as long as any other material – longer even than aluminum, as that is subject to fatigue damage. There’s no evidence that ultraviolet light damages carbon fiber, and no evidence that stiffness reduces over time.

Sources:
http://carlhart.com/how-to/how-to-care-for-carbon-bikes-and-parts-pg220.htm

http://www.ibiscycles.com/support/technical_articles/all_about_carbon/

crikey wrote:The same comment

crikey wrote:

The same comment can be applied to any frame of any material, and I’ve broken steel and aluminium frames…

The idea that every carbon frame is minutes away from ‘catastrophic failure’ is one used by people who don’t like them, and as above, is not related to material science.

Absolutely!

I get tired of hearing armchair engineers telling me my carbon bike is likely to explode at any second sending shards of razor sharp carbon through my gentleman parts!

These are generally the same people who tell me I must never allow a carbon bike to get wet – “It’s likely to degrade it mate” – sure, sure it will. :))

crikey wrote:What a load of

crikey wrote:

What a load of nonsense.

Trek give a lifetime warranty on their frames, I’ve got a 14 year old one that’s still as good as the day it was bought. People change frames because they go out of style, not for any material science reason.

Your cared for carbon frame will last at least as long as any steel or titanium frame.

How do you know your frame is as good as the day it was bought? Have you had it tested? In fact, how does anyone know how close their carbon frame is to catastrophic failure?

If a manufacturer offers a lifetime warranty, that doesn’t mean the product will last a lifetime. It just means the manufacturer has estimated that the extra profit on collective sales will be greater than the cost of servicing that warranty.