Same with tea by the way.

Neither. The data needed to make a bike out of any material with the desired ride characteristics already exists. It is used all the time by the engineers and frame designers in the industry. Just as, say, in the auto industry. My point is that generating new data is not going to solve the mystery of frame material. No mystery exists. New data is not needed to convince the layperson that their misconceptions about frame materials are mistaken. There is already more than sufficient knowledge out in the world to convince an educated and objective audience. The issue is that the majority of the audience in these questions are neither of these things, and will reject data that refutes their beliefs.

My point is that any study such as that proposed by the OP would be redundant and ineffectual. There's nothing in those questions that warrants such attention, especially when it's unlikely that an experiment could be designed to isolate the variables of interest.

That's not to say that there aren't quirks of bicycle handling and ride that don't pop up and surprise us (that's why we do prototypes), and I should hope that the data on these are recorded, since they are useful for future design work. But the question of how frame material affects comfort is neither interesting nor unanswered.

A) People tend to pick apart every word one writes. If my vocabulary has expanded, it's to attempt to use the correct terms and keep this a discussion rather than a pissing match.

B) The 'correct' / 'incorrect' shtick is already taken.

C) Click on the links I posted and learn something. It's not just about the wheels and even with the same geometry there are differences you can feel.

Bring two elitist activities, road cycling, and engineering, and what do you get? An epic thread.:thumb:

Don't worry, this comes from someone who is both a cyclist and an engineering student. I actually plan to build and test a CF road frame for my senior design. I have a few ideas, but I guess we'll see if the data is conclusive, or even useful.

grolby, I think I agree with what you are saying. The material info is available, and we shouldn't expect to find anything new and earth-shattering. But, how much info is readily available on how these material specs come into play with bicycle design? I'm sure the big companies have a lot of test data, but they aren't exactly sharing it. It would be interesting if one of us did some R&D on how these materials react to different frame geometries and shapes. I'm eager to start playing around with a CF frame in Solidworks FEA. It will just be a fun test at first, but I may learn some things when I start digging deeper. I like that CF can be molded to any shape, making the design possibilities endless. Trial and error works well, but a thorough, unbiased test would be an interesting project IMO. Also, why does everyone keep saying that we can't test the frames because we can't ensure they are all set up the same(tires, wheels, etc..)? We are testing the FRAMES, therefore they would be the only item in the test jig. This is standard procedure with all other frame tests. Secure at the dropouts and start your tests. Record the reaction data when it is subjected to a reproduction of high frequency road bumps, then record the reaction data when it is subjected to a smooth but forceful pedal stroke. There will undoubtedly be a lot of complications, and not nearly this simple, but that is why it is engineering.

This stuff is interesting and potentially useful. Why wouldn't we want someone to try it? Nothing to lose but someone else's time.

thats what i was pointing out.

You can say it's crap, but I like Starbucks best. Is that "marketing"... or do those overcooked beans have a distinct taste that I favor?

You need to read (or re-read) the links Fat Boy posted. The rider's weight on the frame totally changed the way the frame responded.

Because I'm an edge case, like most people who own several bikes. I'm definitely a market, but not the biggest one by far.

I'm also fat and slow and have *some* pride, so I ride bikes that don't highlight my deficiencies so much. :D

I dunno, I guess you tell me.

I go to both Starbuck's and Peet's as the mood strikes me, so it's not like I'm on a pedestal looking down. Just calling it as I've seen the analysis of why Starbuck's is the major player and Peet's isn't, even though the same group of people founded both.

I just went back and read them and do not see what you're talking about. I see a suspension test rig link. Am I missing something? Auto frames are tested in a fixed jig and I don't see why we wouldn't test a bike frame the same way. Decrease the independent variables and isolate the system to find out what we want to know.

The bottom of the "page 17" (page 2) scan on the cozybeehive link... "A comparison of Tables 1 and 2 shows that, as expected, the [sic] biker has a strong influence on the dynamics of a bike and almost all the modal parameters are modified. With a [groan] biker, there are only few modes that can be extracted within the 10-100Hz band. Most of the modes on the handlebars are not detectable. Only the first cantilever beam-like mode of the front fork and wheel is similar between the two configurations. The natural frequency of that mode is shifted from 33.5 Hz to 27.8 Hz with the presence of the cyclist."

I'm another edge case that owns several bikes including a 'real' Paramount. Marketing doesn't _always_ win. More often than not, well, yes, I have to concede that.

As a frame of reference, at about 30 Hz, the amplitude of a vibration only needs to be 0.002" (0.05mm) to reach the Meister Threshold of 'Extremely Uncomfortable'. If those amplitudes are knocked in 1/2 to 0.001", then they drop out of the 'uncomfortable' zone and if they're cut in 1/2 again, they would be classified only as 'noticeable'. We're talking about very small changes (in an absolute sense) making a huge difference in perception.

Static testing of an auto frame in a fixed jig is done to determine structural integrity. It verifies welds and support placement. Dynamic testing, as we are speaking of, is done on a 4 or 7 post 'shaker' rig. You can also do structural testing to determine local mount and suspension deflection on something called a 'Kinematics and Compliance Rig'. It's kind of a cross between a fixed jig and a shaker rig.

They all have their place.

Can't believe I wasted the time reading this thread... I guess I'll waste more by posting in it :D

I'll quote one of my professors from my college days, "an engineer is someone who can do for a dollar what any old fool can do for two."


1) I can't believe they're not teaching engineering students to do FEA by hand anymore (I only graduated 5 years ago). I wasn't even allowed to THINK SolidWorks. One of my professors did make a consession and let us program Fortran 77 for FEA... suck. Seriously, I took the SolidWorks classes a three years ago and the newly graduated 'engineers' had no clue how to do FEA without CAD.

2) CF is fun. Depending on the resin, layup and method to set it (heat, pressure, etc), it can have virtually infinite variability in properties.

3) My aluminum w/ carbon seat stays bike was buzzy. My CF is a buttery smooth mountain-goat. That's all that mattered to me when I dropped >$3K on the new sex.

You can become an engineer without learning finite elements, just as you can practice as an engineer without performing any finite element analysis.

Solving finite element models "by hand" ? I hope they at least let you use a slide rule.

True, but it's nice to know how to do it before you let the computer do it for you, otherwise we're glorified drafters. :p

I never had to do FEA as an engineer either... most of my stuff was thermo (semiconductors). Now I'm a bureaucrat. :cry:

I actually have a slide rule, but lost it somewhere.

you paid 3k for sex?
in 2000 i was using mechanical desktop 4.0 when i first started mech. engineering degree. but 9-11 changed a few things and joined the mil.
came back last year to finish the degree...totally and completely different. so much so that i switched majors cause i didn't like it anymore.
anyway who cares whats better. people who believe carbon is better will ride carbon...i will. if you dont believe its better ride what you think is better.

What... uhhh... I get paid!

I started in 2000 too, but joined the AFROTC. I got a scholarship right before 9/11, commissioned in 2004. From 2000 to 2004 (when I graduated), the program changed so much that if I hadn't entered the school of engineering in 2001, the curriculum would have been completely different by 2002.

finally had a chance to read this thread start to finish... btw what was it about again?

He got off cheap.

Let that person be you...you're nominated. Fellow engineer here. I find this discussion somewhat entertaining...including the premise from the OP. Major bike manufactures have their bikes modeled in CAD and likely perform both static and dynamic virtual testing which they correlate with test fixtured frames they strain gage. The magic isn't in the testing be it virtual or functional. The magic is correlating this data to what a human being deems from poor to excellent...in other words correlating quantifiable data with qualitative perception. This all can be done with same boundary conditions, i.e. wheels, tires seat etc as each is a spring with its own forcing function. No doubt manufactures have more data than they know how to interprete. Aluminum is a great frame material if the bike has either a shock, carbon stays and fork or tires wider than 28mm lol.

Yeah, I have to admit I was being overly dramatic. It's hard not to resist sometimes.

PS Paramount owner's club represent!

http://img340.imageshack.us/img340/5715/hfive.gif

I wonder how many Specialized engineers are reading this thread, chuckling lightly, slowly rolling a Zerts insert between their fingers.