I might go back to an aluminium frame (from carbon)

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Marcus Aurelius
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Re: I might go back to an aluminium frame (from carbon)

Postby Marcus Aurelius » 24 Nov 2019, 10:49pm

Cugel wrote:
Smudgerii wrote:
Marcus Aurelius wrote:Unfortunately, it’s something that’s well known about, regarding CF, in many other applications ( aerospace, aeronautics, motorsport) but with cycling, the pro side don’t care, the bikes are used up and sold on, way before any issues become an issue, there is no willing / funds available to do the science. Unfortunately, Joe Schmo sucker public, pay big bucks for the same frame materials, but do care about the durability. Some of the high end / off the shelf, CF built bikes are getting on for 13K now, the CF tech / materials, still suffer the same issues. It’s not as big an issue if you build up from a frameset, but there will be issues if you rely upon ‘off the shelf’ fully built bikes.


Surely if it’s that well known there will be links you can post? Maybe the links will help educate the rest of us


My embolden .... This does seem like scuttebut doesn't it. A summary would be, "There are rumours of problems but no evidence so I'm guessing really".

Cugel

I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0

Polisman
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Re: I might go back to an aluminium frame (from carbon)

Postby Polisman » 25 Nov 2019, 7:29am

My brother has a Cannondale caad12. I always thought it was a bit naff until I had chance to ride it for 80 miles when my own bike was out of commission.

It's a revelation, incredibly good handling and very comfortable over the miles, unlike any aluminium frame I've ever ridden. Not surprising though, as cannondale have been making these frames for over thirty years now. I believe the Caad 12 frame is 1050gr, so zero weight penalty over a mid range carbon frame. They come in painted and anodised finishes, and I believe the anodised one is even lighter.

Would recommend.

Jamesh
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Joined: 2 Jan 2017, 5:56pm

Re: I might go back to an aluminium frame (from carbon)

Postby Jamesh » 25 Nov 2019, 8:19am

I have both Cannondale six 3 and a focus izalco.

The hi mod focus rides much like a 531 Vs a 501 or non butted steel frame....

The c dale has done coast to coast, lejog, winter riding etc but it's a bit dull to ride on, the focus - a pro level hi mod frame is a delight to ride however would I ride the above on it? Definitely not!

Same goes for caad an 8/optimo is a different bike to a 10/11/12

I would use an 8 for commuting and not a 12

Same for carbon a Boardman yes but not a hi mod race bike...

Cheers James

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Cugel
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Re: I might go back to an aluminium frame (from carbon)

Postby Cugel » 25 Nov 2019, 9:13am

Marcus Aurelius wrote:
Cugel wrote:
Smudgerii wrote:
Surely if it’s that well known there will be links you can post? Maybe the links will help educate the rest of us


My embolden .... This does seem like scuttebut doesn't it. A summary would be, "There are rumours of problems but no evidence so I'm guessing really".

Cugel

I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0


Those reports concern delamination of layered CF in resin after the structure is subjected to a sudden blow, not a description of how a CF bike frame can degrade due to normal bike riding stresses or long-term degradation of the material itself, such as occurs in some metals.

As I recall, there are various videos about showing how a poorly-made CF frame can be easily damaged by sudden impacts; but others that show severe abuse to a well-made bike frame with no damage. There seems little or no evidence that a well designed & made bike frame of CF in resin will degrade through time due to either it's inherent inclination to degrade or due to the normal forces on a frame encountered when cycling.

Aluminium, as I understand it, degrades through time all by itself; degrades faster when subject to the flexing forces of normal cycling. Steel is less inclined to do that but can easily go rusty if not well coated. If one crashes a lot, steel may be best; aluminium cheaper to replace; CF in resin pretty tough but fails completely when it does fail. Titanium seems tough too - but expensive to buy and expensive to repair.

Cugel

fastpedaller
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Location: Norfolk

Re: I might go back to an aluminium frame (from carbon)

Postby fastpedaller » 25 Nov 2019, 9:50am

If one is worried about carbon breakages, then it's important to know that (it would appear) most of the aluminium framesets have carbon forks!

NickJP
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Joined: 24 Sep 2018, 7:11pm

Re: I might go back to an aluminium frame (from carbon)

Postby NickJP » 25 Nov 2019, 10:18am

Cugel wrote:Aluminium, as I understand it, degrades through time all by itself; degrades faster when subject to the flexing forces of normal cycling. Steel is less inclined to do that but can easily go rusty if not well coated. If one crashes a lot, steel may be best; aluminium cheaper to replace; CF in resin pretty tough but fails completely when it does fail. Titanium seems tough too - but expensive to buy and expensive to repair.

Aluminium (and its alloys) do not have a fatigue or endurance limit - that is, as the stress is decreased, the number of cycles before failure increases, but you never reach a stress low enough such that the life is essentially infinite. However, with proper design, you're talking an extremely large number of cycles, up in the billions. After all, the great majority of passenger aircraft are constructed of aluminium alloys, and they last for tens of thousands of flying hours of constant vibration without falling out of the sky due to structural failure.

See an S-N diagram below for steel and aluminium - at high stresses, they both fail within a limited number of cycles, but as the stress decreases, steel eventually reaches a stress level where it doesn't fail regardless of the number of cycles, whereas aluminium does not. Diagram from the Wikipedia article on the subject: https://en.wikipedia.org/wiki/Fatigue_limit.

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Manc33
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Re: I might go back to an aluminium frame (from carbon)

Postby Manc33 » 25 Nov 2019, 10:35am

I guess bike frames are made from 6061 aluminium or similar but 7075 is way stronger and more costly. I don't know if 7075 fatigues slower than 6061 but going off how tough 7075 is I would think so. 6061 can be cut like butter whereas 7075 is almost as hard as steel.

I'm probably not going to go back to an aluminium frame :oops:

Ever cut a carbon fork steerer to length? I blunted three junior hacksaw blades cutting that stuff (outdoors, with a mask on).
When two cyclists get married, they should throw anodized cable crimps instead of confetti.

Smudgerii
Posts: 88
Joined: 10 Jul 2016, 8:41pm

Re: I might go back to an aluminium frame (from carbon)

Postby Smudgerii » 25 Nov 2019, 11:35am

Marcus Aurelius wrote:
Cugel wrote:
Smudgerii wrote:
Surely if it’s that well known there will be links you can post? Maybe the links will help educate the rest of us


My embolden .... This does seem like scuttebut doesn't it. A summary would be, "There are rumours of problems but no evidence so I'm guessing really".

Cugel

I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0


So nowhere in there can i find reference to the claims you made. Plenty of reference to impact damage, but that info was already well known.

So glad i read them.... nearly threw away my motorcycle helmet, cycle frame, mobile phone cover and cup. Lucky escape

Marcus Aurelius
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Joined: 1 Feb 2018, 10:20am

Re: I might go back to an aluminium frame (from carbon)

Postby Marcus Aurelius » 25 Nov 2019, 3:32pm

Smudgerii wrote:
Marcus Aurelius wrote:
Cugel wrote:
My embolden .... This does seem like scuttebut doesn't it. A summary would be, "There are rumours of problems but no evidence so I'm guessing really".

Cugel

I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0


So nowhere in there can i find reference to the claims you made. Plenty of reference to impact damage, but that info was already well known.

So glad i read them.... nearly threw away my motorcycle helmet, cycle frame, mobile phone cover and cup. Lucky escape


That’ll teach me to cast pearls before swine I guess. You don’t understand it, that’s fine. If you want to be a smart buttock, try to be more of the former and less of the latter.

Smudgerii
Posts: 88
Joined: 10 Jul 2016, 8:41pm

Re: I might go back to an aluminium frame (from carbon)

Postby Smudgerii » 25 Nov 2019, 3:50pm

Marcus Aurelius wrote:
Smudgerii wrote:
Marcus Aurelius wrote:I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0


So nowhere in there can i find reference to the claims you made. Plenty of reference to impact damage, but that info was already well known.

So glad i read them.... nearly threw away my motorcycle helmet, cycle frame, mobile phone cover and cup. Lucky escape


That’ll teach me to cast pearls before swine I guess. You don’t understand it, that’s fine. If you want to be a smart buttock, try to be more of the former and less of the latter.


What I understand is, you made claims you cannot back up, imo that makes you the “smart buttock”. Before offering me advice what I should “try to be” it would perhaps be best to sip a little of your own medicine.

If, and it’s a big unproven if, CF behaves in the manner you claim. Then why do they manufacture highly flexing items in it? How are race teams like HRC, Ducati Corse able to build in varying amounts of flex and yet remain safe? Motor manufacturers build road cars for the general public to buy?

Surely you have a link that proves your assertions? Or else why would you make them?

Polisman
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Joined: 9 May 2019, 2:23pm

Re: I might go back to an aluminium frame (from carbon)

Postby Polisman » 25 Nov 2019, 4:04pm

Manc33 wrote:I guess bike frames are made from 6061 aluminium or similar but 7075 is way stronger and more costly. I don't know if 7075 fatigues slower than 6061 but going off how tough 7075 is I would think so. 6061 can be cut like butter whereas 7075 is almost as hard as steel.

I'm probably not going to go back to an aluminium frame :oops:

Ever cut a carbon fork steerer to length? I blunted three junior hacksaw blades cutting that stuff (outdoors, with a mask on).


Disk cutter, does the job in seconds. Always wear a mask though because carbon dust is quite a nasty substance.

slowster
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Re: I might go back to an aluminium frame (from carbon)

Postby slowster » 25 Nov 2019, 4:21pm

Marcus Aurelius wrote:
Smudgerii wrote:
Marcus Aurelius wrote:I don’t know whether you can understand this or not, but here goes.

https://www.researchgate.net/publicatio ... c_emission

https://link.springer.com/article/10.10 ... 018-2431-0


So nowhere in there can i find reference to the claims you made. Plenty of reference to impact damage, but that info was already well known.

So glad i read them.... nearly threw away my motorcycle helmet, cycle frame, mobile phone cover and cup. Lucky escape


That’ll teach me to cast pearls before swine I guess. You don’t understand it, that’s fine. If you want to be a smart buttock, try to be more of the former and less of the latter.

I've just skimmed through the beginning of the first link. It talks about the potential for low velocity impacts to cause internal damage to carbon fibre. The introduction gives dropping of a hand tool onto a composite aircraft part during maintenance as an example of how such impacts can occur. The experiment involved striking a peice of carbon fibre with ~2kg at ~6mph and ~8mph with the impact concentrated in a ~13mm diameter circle by an indenter. Such a test does not support your assertion that
Marcus Aurelius wrote:CF deals with / dissipates shock, by forming new surfaces, and Carbon frames ‘scar’ over time, which makes their handling properties change

You might be correct, but the links you have provided do not appear to support your rather sweeping assertions, which makes me suspect that you are not as knowledgeable about this subject as you would have us believe.

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willcee
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Re: I might go back to an aluminium frame (from carbon)

Postby willcee » 25 Nov 2019, 4:42pm

Some on here will remember whom I refer to, Norris Lockley of Settle N yorks.. Bespoke Cycles was his trading name, Norris you may or not remember was the first UK dealer to bring in CARBON FRAMES back in the day , of French manufacture, and their name escapes me yet Lemond and Hinault won the TDF on them.. the later ones were known as RBE, and Corima wheels which he also brought over.. the reason for the French being the first with Carbon is linked to their love of the bicycle and their extreme knowledge in Rocketry and missile developement for the French gov. where carbon tubes were in abundance... asking him about the material some years ago he said that their experts naming several that he knew well, claimed that it aged like wood given half a chance without any sharp strikes or fretting to the outer skins.. personally its a fancy plastic.. some is better than others yet when the military and aircraft industry ''life it in harness'' that has to say something about longevity under use.. those boys take zero chances.. will
Last edited by willcee on 25 Nov 2019, 6:53pm, edited 1 time in total.

hoppy58
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Re: I might go back to an aluminium frame (from carbon)

Postby hoppy58 » 25 Nov 2019, 6:45pm

Something that hasn’t been mentioned is that, as I understand it, Alu and steel frames can be recycled at the end of their life, whereas cf frames can’t and will end up in landfill. Personally I like steel, but my last road bike was a kinesis alu, which was really comfortable!

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Cugel
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Re: I might go back to an aluminium frame (from carbon)

Postby Cugel » 25 Nov 2019, 10:32pm

Smudgerii wrote:
Marcus Aurelius wrote:
Smudgerii wrote:
So nowhere in there can i find reference to the claims you made. Plenty of reference to impact damage, but that info was already well known.

So glad i read them.... nearly threw away my motorcycle helmet, cycle frame, mobile phone cover and cup. Lucky escape


That’ll teach me to cast pearls before swine I guess. You don’t understand it, that’s fine. If you want to be a smart buttock, try to be more of the former and less of the latter.


What I understand is, you made claims you cannot back up, imo that makes you the “smart buttock”. Before offering me advice what I should “try to be” it would perhaps be best to sip a little of your own medicine.

If, and it’s a big unproven if, CF behaves in the manner you claim. Then why do they manufacture highly flexing items in it? How are race teams like HRC, Ducati Corse able to build in varying amounts of flex and yet remain safe? Motor manufacturers build road cars for the general public to buy?

Surely you have a link that proves your assertions? Or else why would you make them?


I do enjoy a flounce-out by a Duchess of Pout after she is caught claiming to be The Queen. :-)

Cugel, a pedantic gluteus maximus.