Carbon Stays vs. Full Carbon
xbenhanleyx
Posts: 73
I love the idea of upgrading my frame from 7005 series aluminium to a lighter and more comfortable carbon frame. But, I am struggling to justify the cost to myself, particularly when there seems to be frames out there with alu bodies and carbon stays, weighing in at around 1kg and costing less than full carbon.
I would be interested to know people's opinions on whether a full carbon frame gives any more of an advantage on comfort and performance over a lightweigth aluminium frame with carbon rear stays.
Thanks.
I would be interested to know people's opinions on whether a full carbon frame gives any more of an advantage on comfort and performance over a lightweigth aluminium frame with carbon rear stays.
Thanks.
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Comments
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Not ridden the alu/carbon bikes, but my full carbon tcr is very comfortable.
Alu will fail eventually - and I feel that the joins of the two materials would be a weak point.
There seem to be some fantastic carbon frames out there at the moment anyway - Planet X do some great bikes - but they are whole bikes not frames.0 -
Just to throw a spanner in the works but Cannondale's SystemSix has a full carbon front triangle which is joined to an aluminium rear triangle!
SystemSix0 -
JustRidecp wrote:Just to throw a spanner in the works but Cannondale's SystemSix has a full carbon front triangle which is joined to an aluminium rear triangle!
SystemSix
And some Lemond bikes have a carbon top half stuck on a ti or steel bottom half!?!0 -
I'd suggest you're not likely to gain a lot (if anything) on your current alu frame by going to one with a carbon back end. Not without spending more than you can get a decent full carbon one for - I've just ordered one from http://www.pedalforce.com/ which will come in at ~£400 after paying UK tax on it.0
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xbenhanleyx wrote:I would be interested to know people's opinions on whether a full carbon frame gives any more of an advantage on comfort and performance over a lightweigth aluminium frame with carbon rear stays.
Thanks.
It's hard to generalise because carbon allows frame builders to build frames with very different characteristics.
I can give you a direct comparison of a full carbon and an alu/carbon frame from my own stable though:
- my full carbon frame (Bianchi 928L) could never be described as 'comfy' and seems to transmit every bump straight up your spine. After 3+ hours it can really start to p1ss you off. Those stretches of depleted tar really shake your filllings out, and there are times when I just wish I could climb off. It goes fast though!
- on the other hand my alu/carbon rear end frame (Trigon EX) just floats over everything - it's like having 1/2" of suspension and you barely notice road imperfections.
I think that's more down to the shape of the seatstays than anything to do with materials though..0 -
Not in this case: I run the same wheels and tyres at the same pressure on both bikes, and the geometries are near identical.
The Trigon claims to have a 'viberation(sic) absorbing carbon rear end with Obllix section upper wishbone' ! - and it seems to work..0 -
cougie wrote:
Alu will fail eventually
On what basis do you make this assumption? Aluminum has been used in aircraft manufacture for donkeys years and is subjected to much higher stresses than a bike frame.0 -
As for the carbon/aluminium joint failing - what is he on? Go away and read up on materials science if your need to, but this level of unqualified information in wrong and misleading. If you can only spring to a carbon/ally frame, then look for one with a full carbon rear end i.e. chainstays and seatstays, so effectively you have the back end of a carbon bike.Make mine an Italian, with Campagnolo on the side..0
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Justride - just about every forum has tales of Aluminium frames failing. There was a good test that one of the German bike mags ran and they put frames through so many 'cycles' until they failed. Some of the Aluminium frames were the worst. Its a good material, but can be made into a harah frame, and its lifetime isnt as long as you may get with steel or titanium.
But most of us would have fallen in love with a new frame before the bike starts to fail.
As to the joints failing - I did say it was only a feeling. I remember most of my clubmates' vitus bonded frames having to be sent away when they started to come loose. And didnt Hincapie crash in Paris Roubaix when his Alu steerer parted company with his carbon fork ?
As the ride characteristics of all these frames can vary so much - I'd try it before buying it if you can. Carbon can be very comfy, or far too rigid. My TCR seems to fall into the former though.0 -
I agree, it depends on how 'flexy' they make the carbon.
Someone did tell me that carbon ended alu frames are easier to align and have cheaper production costs than all alu frames. The same person said a carbon rear end will make little difference and the seatpin choice is much more significant. Don't know how true this is, but personally I wouldn't pay more for a carbon ended frame.
I'm sure that the bonding process between carbon and alu isn't an issue - it may even be the strongest part of the bike if they do it right!
Test rides are the only reliable way to tell. A high end alu frame will be hard to beat (with or without carbon stays).'Happiness serves hardly any other purpose than to make unhappiness possible' Marcel Proust.0 -
JustRidecp wrote:cougie wrote:
Alu will fail eventually
On what basis do you make this assumption? Aluminum has been used in aircraft manufacture for donkeys years and is subjected to much higher stresses than a bike frame.
Is this why aircraft are inspected regularly and parts given a definite life and then replaced. Also, what about the DH Comets which fell out of the sky due to metal fatigue ?0 -
blackhands wrote:JustRidecp wrote:cougie wrote:
Alu will fail eventually
On what basis do you make this assumption? Aluminum has been used in aircraft manufacture for donkeys years and is subjected to much higher stresses than a bike frame.
Is this why aircraft are inspected regularly and parts given a definite life and then replaced. Also, what about the DH Comets which fell out of the sky due to metal fatigue ?
Ok. First of all I'm not an engineer so please be kind but I didn't think it was the airframe of the DH comets that failed but it was something to do with the shape of the windows creating a weakness in the skin of the aircraft which lead to rapid decompression. My flat mate throughout uni was a mechanical engineer and he did a project on the DH Comets and I'm sure this is what he told me the failures were due to. Therefore its a design, not a materials flaw.0 -
I believe they had square portholes - the corners led to it cracking.
Oh and one of the first posts i read on another forum - guy was complaining about his alu frame having cracked - so it does happen in the real world.
More stuff on alu for you : http://www.anvilbikes.com/?news_ID=16&catID=3
From a framebuilder who does this kind of thing for a living.0 -
Thanks. Interesting article.0
