Weight Weenies

I'm a sucker for the Madone's integrated brakes and it allows me to be a jerk-off and call it a Mad One, so my vote goes there. I mean, the RCA wins hands down, but it's not exactly in the same price bracket as the others.

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I would add the Guru Photon Hyperlight to the mix as well. It's $8,500 but is custom and 670g

http://www.gurucycles.com/frames/featur ... photon-hl#

Link

Added: Guru's record of matching their mass claims is poor. The number from a show bike isn't necessarily a reliable guide. Cervelo's numbers are proven reliable.

Cheers to andy2 for a class response -- when someone challenged him, he mentioned they were hiring! So many people get defensive as a first reaction.

andy2, if you needed UX people, and were on the same continent, I'd be sending you my resume and portfolio... .

andy2 wrote:Lastly on monocoques versus tube to tube: please note that neither the RCa nor the Trek nor Cannondale are true monocoques.
They are 'multi-coques' where the main frame is assembled from different pieces and glued into a separate bb piece.
Our bike however is a monocoque where the entire main triangle, along with bb & headtube including bearing races, is molded in one piece with continuous fibers throughout.
Being bespoke, we also don't need to play averages when calculating the layup for the rider/a

That's not what monocoque means. A monocoque is a structure that has no internal framing or support, but rather uses the outer shell to support the structure. A monocoque can be made of one piece or a hundred pieces, so long as there isn't internal framing lending support. Sorry, I just feel the need to be pedantic sometimes.

sigismond0, so basically all frames are monocoque by your definition. In the bike world there´s two vastly different build methods for carbon frames.
One are tube to tube and the other one is monocoque without joints in the front triangle.

Many bigger frame companies boasting with monocoque and custom frame building like Argonaut and Trek madone et al.
That´s not entirely correct as they glue up molded up parts to represent a front triangle. These glue joints is a big no no for me and many others as it is basically a cost cutting and production speeding process.
You get a double thick joint with very weak glue joint between carbon parts. Bear in mind a finished laminate of carbon/resin mix are around 2000-3000 mpa in tensile strength where the glue have around 30 mpa as tensile strength. In Formula 1 chassis tub you will never ever see this type of joint.
So my opinion is glued up joints in the front triangle is a big shortcut that compromises too much of the frame´s qualities like riding feel and stiffness/compliance ratio.
Reusing the same parts to make different frame sizes by alternating lengths, that´s one part of the cause of weird stack and reach graphs you see, a another cost cutting feature.
For me, with a high price tag, a separate complete front triangle mould for each frame size is mandatory, nothing else is good enough.

Sigismond0, we are getting deep into semantics here. So to be extra pedantic back, I used the term in a literal sense where Mono = single & Coque = shell.
So by monocoque I mean a single stressed skin structure, like a ping pong ball.
In a broader sense I guess you could make the case that a joined multishell structure is monocoque with the glue taking up the stress, yes.
It rather dilutes the concept though.
But you could actually also make a case for a composite structure never qualifying as a true monocoque by being a system rather than a continuous material!
By your definition of a monocoque the Cervelo RCa is still not a monocoque by virtue of the fact that it uses bulkheads;)!

In short I believe that terms like 'monocoque' are best understood in the simplest most literal sense..

/a

So for us less knowledgeable about joined multishell structures ect…

Is the construction of the Rca and the Evo Nano comparable?

From what I can tell the finished products are very comparable and it looks like both are fantastic framesets. The one difference that I can see is the bottom bracket. The Evo does not need cups so you save on the weight of cups. This was also the case with the R5ca. The Rca now needs cups that weigh 40-50 grams. But then the Evo is limited to cranks that allow the bearings to be inset and your choices are limited. The Cannondale crank is your most logical solution and not a bad solution. You of course can install a THM Pressfit30 bottom bracket and that will move the bearings out and then you can install any of the popular light cranksets and use your favorite chainrings like Praxis Works. But then you just added the weight of cups. In the end the built up weighs for both bikes will be very similar.

Mattias Hellöre wrote:sigismond0, so basically all frames are monocoque by your definition. In the bike world there´s two vastly different build methods for carbon frames.
One are tube to tube and the other one is monocoque without joints in the front triangle.

It's not my definition. That's the actual definition of the word. Most carbon frames are monocoque! Metal bikes are not monocoques due to the way the tubes meet each other and where stresses fall.

andy2 wrote:Sigismond0, we are getting deep into semantics here. So to be extra pedantic back, I used the term in a literal sense where Mono = single & Coque = shell.
...
In a broader sense I guess you could make the case that a joined multishell structure is monocoque...It rather dilutes the concept though.
...
By your definition of a monocoque the Cervelo RCa is still not a monocoque by virtue of the fact that it uses bulkheads;)!
...
In short I believe that terms like 'monocoque' are best understood in the simplest most literal sense..

Again not my definition. It's not really a broad sense, diluted concept, or anything like that. The word has an actual meaning and you really ought not argue that it means something that it doesn't. Carbon bikes are monocoques unless there's some other structure inside them, like older frames with alloy reinforcements within the tubes or if the structure is like welded bikes. Most carbon frames have mitered lugs which are seamless to the tubes on both the inside and outside, which is still a monocoque. You're making a distinction between one-piece and multi-piece construction, which has exactly nothing to do with whether a structure is a monocoque.

You're all welcome to use whatever made-up or "literal" meaning you like; however, you ought to keep in mind that when you use technical terms incorrectly, you're spreading disinformation to everybody that reads it and doing a disservice to the forum.

If you want to make the distiction that other manufacturers use multi-piece construction, say that they use multi-piece construction and that you have a one-piece main triangle. If you intend to use an engineering term like monocoque, use it correctly. Doing anything else is just plain wrong.

(Just to clarify, I've nothing against anybody here nor am I trying to make any statements about the superiority of one-piece vs multi-piece construction. It just grinds my gears when people use words to mean something they they absolutely don't mean, and I have to do my part to ensure that anybody who reads this thread is fully informed.)

Steady on there! I do know what a monocoque is and so do a great many people here on the forum.
It's just that in the cycling industry it's come to mean something slightly different and is widely used to differentiate from so called 'tube to tube' construction.

Yes the class room definition of monocoque is any structure where the skin carries the load and there is no frame or bulkheads etc.
Most of us here on WW's can google 'monocoque', a good few have degrees in engineering..

The problem is that the term monocoque will then also include any composite tube to tube frame like a Colnago or a Parlee Z1...

I think to be meaningful for the cycling community and not misleading that it should mean a continuous stressed skin structure.

I'm not sure I agree with you 100%, but I do certainly understand where you're coming from. My beef is with the intentional misuse of "monocoque" instead of just saying continuous or something along those lines. Why bastardize a word when you can just use the correct one to begin with?

I don't see how its a problem that multi-piece carbon frames also fall under the monocoque umbrella. Its only a problem when some people use one definition of monocoque while others use a different definition, which is easily fixed. There is definitely a problem in the cycling community wherein most people assume that monocoque means one-piece construction and don't realize that it's actually a type of structure. People will tend to use the root of a word to assume its definition--in this case "one shell"--and that leads to confusion (I'll admit, even I misused the word for some time!). I think we can agree that this is the incorrect usage of the word, but if most people use it that way...well, that's just how language evolves and I can't really argue with that.

I'm not familiar with exactly how the Colnago or Z1 frames are constructed, but if they're what they look like (lugged composites), then I don't believe that counts as a monocoque. Or if it does, then any lugged metal frame is as well.

sigismond0 wrote:It's not my definition. That's the actual definition of the word.

Even the non-technical among us have no issues understanding the definition of the word. However, this is a cycling specific forum and in our subset of the population the common use of "monocoque" is exactly as it has been used here. Andy was clear in communication the differences in frame construction and I think everyone reading the thread understood his explanation.

An attempt to reverse the common usage industry wide seems sisyphean at best. Arguing otherwise seems a childish attempt to prove ones intellectual superiority. Clarification doesn't require a supercilious attitude, even on the internet.

sigismond0 wrote:I think we can agree that this is the incorrect usage of the word, but if most people use it that way...well, that's just how language evolves and I can't really argue with that.

I started my last reply before this was posted. I think that is exactly the right attitude.

xjbaylor wrote:

sigismond0 wrote:I think we can agree that this is the incorrect usage of the word, but if most people use it that way...well, that's just how language evolves and I can't really argue with that.

I started my last reply before this was posted. I think that is exactly the right attitude.

Haha, glad we're all on the same page then. I really wasn't trying to flash my giant e-peen and denounce all the dimwits who don't know what words mean. I was just trying to clarify what I perceived as a misused word, which wasn't as misused as I believed.

If most people in the cycling community use monocoque to mean one-piece, then that's what it means. It'll make me a little sad to see such a nice word lose its meaning, but such is the way of language.

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Some days I love WW.
I was just bringing attention to the excellent looking work Andy does and first it turns into an in depth discussion of frame building techniques and then a discussion of language theory. Fantastic.
Jargon is a fun and ever changing thing. Being a doctor is a great lesson in the accepted common misuse of technical terms. No other industry misuses its jargon like medicine. I won't go and repeat the excellent points above about the ever changing nature of language. I would like to say though that I feel sigis has a very good point in that if there is one field we should really try to lock down the Jargon and be very specific with meaning it is probably engineering. I now know that I have misunderstood the word monocoque.
I bet this isn't what the OP was expecting when he posted his question about which of these amazing frames to buy. (buy the Rolo)