Ali v Carbon
Comments
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Just to throw another option into the mix. If someone invented steel now it would be regarded as a wonder material. A good modern steel frame might build up into a bike that weighed a pound or so heavier than carbon. It would be durable and could be custom built for pretty well whatever characteristics were required by the rider. As regards the extra weight, how many on here couldn't fairly easily lose a couple of pounds.
I've lost 17lbs in weight since September and now have an effectively weightless steel bike that fits me like a glove. Unlike the many 'me too' carbon frames that I see around, my bike is unique, and fits me like a glove. I know where I would spend my money if I was buying another new bike. Thing is I don't need to and probably won't need to for many years given how much pleasre my current one gives me!0 -
Here's a take on "comfort". Go to the "Where Comfort Comes From" part.
www.sheldonbrown.com/frame-materials.html0 -
Nickwill wrote:Just to throw another option into the mix. If someone invented steel now it would be regarded as a wonder material. A good modern steel frame might build up into a bike that weighed a pound or so heavier than carbon. It would be durable and could be custom built for pretty well whatever characteristics were required by the rider. As regards the extra weight, how many on here couldn't fairly easily lose a couple of pounds.
I've lost 17lbs in weight since September and now have an effectively weightless steel bike that fits me like a glove. Unlike the many 'me too' carbon frames that I see around, my bike is unique, and fits me like a glove. I know where I would spend my money if I was buying another new bike. Thing is I don't need to and probably won't need to for many years given how much pleasre my current one gives me!
In principle all materials can be used for customised frames. In practice only steel is easy enough to work with, to allow an "almost shed-like" build-up.
Carbon fibre has been introduced in the era of mass production, so there are very few customised applications... formula 1 is one of them, where parts are individually built by laying up and resin injection molding... the costs involved are horrendous.
I am for steel too, merely for estethic reasons I have to say... I like small diameter tubes and I appreciate a good custom paintwork. I've had steel bikes, aluminium, and rode a hired carbon one for a few days... there is no significant difference in the ride in my view.left the forum March 20230 -
Back to about answer one I guess. Ti rides like steel with the weight advantages of Ally. You get your narrow tubes if you want. Prang Carbon you're biffed. It has huge advantages in racing where multidirectional layup allows stiffness and weight loss to be designed in. If someone else is paying for your frame you're sorted.Neil
Help I'm Being Oppressed0 -
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redddraggon wrote:I crashed my Carbon bike 4 times and it was fine
From the looks of your picture you didn't fare nearly as well as the bike.0 -
for the carbon vs ally vs Ti etc debate if you have a browse a materials selection package putting in criteria such as E/density that you wish to maximise there is one material that keeps on coming out best that is unidirectional CRFP. The way the composite is made (directions of the fibers, ammounts of the fibers) affects the "feel" of the component it's used to manufacture. Cannondale have brought out a mountain bike that uses a rear swingarm fixed to the mainframe (no bushes or bearings) allowing the carbon swingarm to flex whilst being damped by the shock so plenty of flex can be built into carbon frames giving them comfort.0
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I posted this on a similar topic a few weeks ago and its an excellent article about frame materials and makes a lot of sense....by the way I like steel so I am slightly biased
http://www.rivbike.com/article/bicycle_ ... _materials0 -
balthazar wrote:
These considerations are doubtlessly very relevant if the matter at hand is, say, the harmonics of a musical instrument. All materials have a harmonic response that varies in many interesting ways.
To exempt yourself from the placebo effect is over-confident.
i know , i have engineering degree, i know about resonance and the harmonic frequence of a system can be built far differently from its components. were not talking about a tuned instrument, we are talking about harsh road jarring.
you can say that about anything , steels a placebo so is tiatanium etc etc.
ok lets talk about failure. if you run into something your bikes pretty much wrecked whatever its is. also people - bones are composite materials and break in a similar way to carbon fibre. i dont remember anyone going around being hysterical about their legs suddenly failing and snapping off. we know they break so dont jump of rooftops accordingly.0 -
I suppose one of my reservations about carbon relates to the prevailing attitude that if it's not carbon, it is inferior. There are regular posts on here from people getting excited at the prospect of 'upgrading' to carbon fibre. The pros ride carbon because every gram counts. At pro level, carbon fibre frames will be of the highest quality. In addition manufacturers want to sell carbon frames because they provide the best profit margin.
A top end carbon frame will make a top quality bike as will a top end one in aluminium, steel or titanium.
Arguably at the budget end of the market a more durable, better riding and handling bike might be had in the more traditional materials.
A problem for me with a lot of budget carbon frames is the lack of individuality. That, and the fact that there is no way of knowing the manufacturing quality of the frame just by looking at it.0 -
Nickwill wrote:I suppose one of my reservations about carbon relates to the prevailing attitude that if it's not carbon, it is inferior. There are regular posts on here from people getting excited at the prospect of 'upgrading' to carbon fibre. The pros ride carbon because every gram counts. At pro level, carbon fibre frames will be of the highest quality. In addition manufacturers want to sell carbon frames because they provide the best profit margin.
A top end carbon frame will make a top quality bike as will a top end one in aluminium, steel or titanium.
Arguably at the budget end of the market a more durable, better riding and handling bike might be had in the more traditional materials.
A problem for me with a lot of budget carbon frames is the lack of individuality. That, and the fact that there is no way of knowing the manufacturing quality of the frame just by looking at it.
I agree.. there's another thing... the PROs ride the bikes the sponsor provides... not that they have much of a choice.
In the past, for races like Paris-Roubaix, they used to have custom made reinfoced frames, "dressed" like commercial frames...in all indistinguishable... I don't know if it's still the case... but I very much doubt big riders like Boonen or Cancellara rely on a commercial sub-kilo frame for the pave'left the forum March 20230 -
ugo.santalucia wrote:redddraggon wrote:ugo.santalucia wrote:redddraggon wrote:ugo.santalucia wrote:sadly there is no tension for a bike frame
You aren't even an engineer are you?
A bike frame is not subject to particular tensile stress, it's the diamond geometry.
In such a 3-dimensional structure there will be both tensile and compressive stresses.
What about when you are sprinting of the saddle? You are flexing the frame......
I think the majority of catastrophic failures are due to compressive stresses (potholes, roughness on the fork and downtube)... flexing-bending (heavy on carbon bars).
Carbon per se wouldn't be a drama... if you're not doing the Paris-Roubaix (remember Hincapie in 2008?) the lack of carbon is a serious problem.... 900 grams... there is very little material there.
Wouldn't hitting a pothole result more in tensile stresses being applied to some of the frame? The forward momentum is being suddenly resisted by the impact on a pothole which I would have thought would result in tension on the front face of the fork / head tube and top surface of the top tube. Without research I would suggest that most pothole damage is as a result of the forward movement of the bike rather than the downward impact of the bike dropping unless it's a seriously big hole :shock:0 -
Pross wrote:ugo.santalucia wrote:redddraggon wrote:ugo.santalucia wrote:redddraggon wrote:ugo.santalucia wrote:sadly there is no tension for a bike frame
You aren't even an engineer are you?
A bike frame is not subject to particular tensile stress, it's the diamond geometry.
In such a 3-dimensional structure there will be both tensile and compressive stresses.
What about when you are sprinting of the saddle? You are flexing the frame......
I think the majority of catastrophic failures are due to compressive stresses (potholes, roughness on the fork and downtube)... flexing-bending (heavy on carbon bars).
Carbon per se wouldn't be a drama... if you're not doing the Paris-Roubaix (remember Hincapie in 2008?) the lack of carbon is a serious problem.... 900 grams... there is very little material there.
Wouldn't hitting a pothole result more in tensile stresses being applied to some of the frame? The forward momentum is being suddenly resisted by the impact on a pothole which I would have thought would result in tension on the front face of the fork / head tube and top surface of the top tube. Without research I would suggest that most pothole damage is as a result of the forward movement of the bike rather than the downward impact of the bike dropping unless it's a seriously big hole :shock:
I would be tempted to define tension as only along the axes of the tubes, as if pulling the two sides... so I would say no.
There is definitively compression stress on the fork, proportional to the drop and to the weight the rider puts on the bars. There is bending stress on the bars...
These are the parts that fail the easiest, under these circumstances... if weak.
It's worth noting that an aluminium handlebar will absorb some of the energy, the carbon one will just snap... one can imagine the consequences in the two casesleft the forum March 20230 -
ugo.santalucia wrote:Pross wrote:Wouldn't hitting a pothole result more in tensile stresses being applied to some of the frame? The forward momentum is being suddenly resisted by the impact on a pothole which I would have thought would result in tension on the front face of the fork / head tube and top surface of the top tube. Without research I would suggest that most pothole damage is as a result of the forward movement of the bike rather than the downward impact of the bike dropping unless it's a seriously big hole :shock:
I would be tempted to define tension as only along the axes of the tubes, as if pulling the two sides... so I would say no.
You can't pick and choose when you have compression/tension. Accrding to you then, compression is only when the stress is parallel to the axes.
There is definitely TENSION in those circumstances. I suggest you brush up on your tensors:
http://en.wikipedia.org/wiki/Tensor0 -
[quote="ugo.santalucia
I would be tempted to define tension as only along the axes of the tubes, as if pulling the two sides... so I would say no.
There is definitively compression stress on the fork, proportional to the drop and to the weight the rider puts on the bars. There is bending stress on the bars...
These are the parts that fail the easiest, under these circumstances... if weak.
It's worth noting that an aluminium handlebar will absorb some of the energy, the carbon one will just snap... one can imagine the consequences in the two cases[/quote]
There may be a compressive force being applied but the stress which is likely to cause failure is surely from tension that force creates within the member? If you look at the photos of Hincapie's bike from what I can tell the steerer sheared off just above the head tube. I can't see any way in which that failure could be due to compressive failure. I'm struggling to think of a likely way that a bike would suffer damage due to a lack of compressive strength unless something were to drop on the frame.0 -
I am not convinced at all by your arguments... both of you... don't want to argue on this, I'm just totally unconvinced.
I can't stop thinking that the vast majority of load on a tube will either be compressive or it will be some form of bending.
Unless you mean that the lack of elasticity and the inability of absorb energy when compressed violently (e.g. pothole), will cause as a reaction a tensile load... which is an argument... but then where is all this alleged ability to dissipate vibrations?
There isn't any... which proves the other part of my argument
Plus, if the stress was tensile CFC wouldn't fail as it's got the best tensile properties... but it does more frequently than the other materials...
If tensile load was dominant then you expect to observe elongated steel tubes, rather than bent ones...
I'm still unconvinced... :shock:left the forum March 20230 -
ugo.santalucia wrote:I can't stop thinking that the vast majority of load on a tube will either be compressive or it will be some form of bending.
bending = compressive AND Tensile!!!!
Jeezugo.santalucia wrote:Plus, if the stress was tensile CFC wouldn't fail as it's got the best tensile properties... but it does more frequently than the other materials... [/img]
There's more to material properties than simply Young's Modulus.0 -
ugo.santalucia wrote:I am not convinced at all by your arguments... both of you... don't want to argue on this, I'm just totally unconvinced.
I can't stop thinking that the vast majority of load on a tube will either be compressive or it will be some form of bending.
Unless you mean that the lack of elasticity and the inability of absorb energy when compressed violently (e.g. pothole), will cause as a reaction a tensile load... which is an argument... but then where is all this alleged ability to dissipate vibrations?
There isn't any... which proves the other part of my argument
Plus, if the stress was tensile CFC wouldn't fail as it's got the best tensile properties... but it does more frequently than the other materials...
If tensile load was dominant then you expect to observe elongated steel tubes, rather than bent ones...
I'm still unconvinced... :shock:
I give up.
This is like arguing with Will. I can never be right with him, because he can never grasp the complexities of my argument.
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redddraggon wrote:ugo.santalucia wrote:I am not convinced at all by your arguments... both of you... don't want to argue on this, I'm just totally unconvinced.
I can't stop thinking that the vast majority of load on a tube will either be compressive or it will be some form of bending.
Unless you mean that the lack of elasticity and the inability of absorb energy when compressed violently (e.g. pothole), will cause as a reaction a tensile load... which is an argument... but then where is all this alleged ability to dissipate vibrations?
There isn't any... which proves the other part of my argument
Plus, if the stress was tensile CFC wouldn't fail as it's got the best tensile properties... but it does more frequently than the other materials...
If tensile load was dominant then you expect to observe elongated steel tubes, rather than bent ones...
I'm still unconvinced... :shock:
I give up.
This is like arguing with Will. I can never be right with him, because he can never grasp the complexities of my argument.
I was actually thinking your arguments were too simplistic... is simplisitc a word or have I just made it up?
Anyway... the all point of discussions is to go on forever and ultimately disagree, so I think we're doing quite well...left the forum March 20230 -
I think this whole discussion really supports my theory that of all the known things on Earth, bicycles are the one thing we know least about. It's as if, the more you know about them, the less you know. :? :? :?0
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dennisn wrote:I think this whole discussion really supports my theory that of all the known things on Earth, bicycles are the one thing we know least about. It's as if, the more you know about them, the less you know. :? :? :?
I thought Toledo was in Spain... in fact I've been to Toledo many years ago... how does it compare with Toledo Ohio?
Do you carry a gun when you cycle? 8)left the forum March 20230 -
ugo.santalucia wrote:dennisn wrote:I think this whole discussion really supports my theory that of all the known things on Earth, bicycles are the one thing we know least about. It's as if, the more you know about them, the less you know. :? :? :?
I thought Toledo was in Spain... in fact I've been to Toledo many years ago... how does it compare with Toledo Ohio?
Do you carry a gun when you cycle? 8)
I think they speak a funny language in Spain, but other than that.....0 -
dennisn wrote:ugo.santalucia wrote:dennisn wrote:I think this whole discussion really supports my theory that of all the known things on Earth, bicycles are the one thing we know least about. It's as if, the more you know about them, the less you know. :? :? :?
I thought Toledo was in Spain... in fact I've been to Toledo many years ago... how does it compare with Toledo Ohio?
Do you carry a gun when you cycle? 8)
I think they speak a funny language in Spain, but other than that.....
In my head, roads in Ohio are all straight, so you don't really need a headset... you can ride a fixed-fork bike and bend like hell if you have to turn at the lights... or you can bounce the front wheel left or right...
One way or the other... who needs bearings in Ohio?
Beside my cheap humour... is it all flat or you've got some good climbs round there?left the forum March 20230 -
Sounds like a great PhD project for a materials scientist to me. Input some vibrating forces at the dropouts (measured on a bumpy Manchester road perhaps) and measure acceleration at the saddle and bars. All you need is 4 frames of the same geometry made from straight tubes (steel, Ti, Al and Carbon composite).
I can't believe in all the things that have been measured and tested that someone somewhere hasn't done this already!?!
Maybe the Science and Engineering Research Council (or whatever they are called now) could fund it. I'd even do the gig myself but I'd need a year to gather the input forces from the most demanding roads in the world (Belgian cobbles, Alpine passes, Aussie dirt roads etc... ) so the travel costs could be pretty high.
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ugo.santalucia wrote:dennisn wrote:ugo.santalucia wrote:dennisn wrote:I think this whole discussion really supports my theory that of all the known things on Earth, bicycles are the one thing we know least about. It's as if, the more you know about them, the less you know. :? :? :?
I thought Toledo was in Spain... in fact I've been to Toledo many years ago... how does it compare with Toledo Ohio?
Do you carry a gun when you cycle? 8)
I think they speak a funny language in Spain, but other than that.....
In my head, roads in Ohio are all straight, so you don't really need a headset... you can ride a fixed-fork bike and bend like hell if you have to turn at the lights... or you can bounce the front wheel left or right...
One way or the other... who needs bearings in Ohio?
Beside my cheap humour... is it all flat or you've got some good climbs round there?
Most of the state is flat as a pancake. Most of the major climbs are highway overpasses.
We do however have some of the best maintained roads in the country. Even the "middle of nowhere" roads are smooth and well kept.0 -
why does everyone, think that by spending loads of money on a carbon frame will negate the fact that most of you out there are over weight, and unfit, ride a sportive and you see most of the field crawling uphill on three thousand + bikes. on its own a bike is ananimate object, it will only go fast if you make it. get a bike you can afford, not one you have to remortgage in order to by it. ride it as much as you can and see what happens, when you ride a bike for the joy of riding a bike.0
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I suggested something along those lines earlier in the thread– together with my vague recollection of just such. However, I suspect that those who are equipped to set up such an experiment wouldn't be interested: either because all they might hope to determine is textbook knowledge already, just waiting to be looked up; or because they'd adjudge it a worthless experiment, with no clear hypothesis to prove. Material science is well investigated, as people in the field could attest; I don't think bicycles bring anything new to the table.Ariege cyclist wrote:Sounds like a great PhD project for a materials scientist to me. Input some vibrating forces at the dropouts (measured on a bumpy Manchester road perhaps) and measure acceleration at the saddle and bars. All you need is 4 frames of the same geometry made from straight tubes (steel, Ti, Al and Carbon composite).
I can't believe in all the things that have been measured and tested that someone somewhere hasn't done this already!?!0 -
My roads are opposite: all hills, but terrible road surface! I'm effectively a mountain biker, in comparision. I get so bored riding the flat, though: does strong wind spice up your rides? Or is it all metronomic regularity?!dennisn wrote:[Most of the state is flat as a pancake. Most of the major climbs are highway overpasses.
We do however have some of the best maintained roads in the country. Even the "middle of nowhere" roads are smooth and well kept.0
