I am astonished that people like you continue to believe that common beliefs about frame materials and their intrinsic effect upon ride are the result of insufficient data.

well if you were just testing the frame material you would just need to see what material dampens vibrations better.
http://www.sheldonbrown.com/frame-materials.html
after reading this i have come to the conclusion that it comes down to geometry and not material, although some materials may help, it would not be substantial enough to change your mind. the geometry would more likely cause the "feel"
and yes, i am an arm chair engineer because i quit my Mechanical Engineering degree. But sheldon browns page makes alot of sense.

O.K. Now close the circle. You have your frequency data from a few hundred bicycles riden for a few hunderd miles. Explain how you take that data and through analysis determine the ride comfort of materials.

Obviously, it's impossible to "determine the ride comfort of materials". At best, one could only hope to see patterns of vibrations that different frames exhibit.

I'm a "ride quality" skeptic. So if I had data from a few hundred bikes ridden from a few hundred miles, and if I saw that bikes with material A tended to have a characteristic vibration spectrum, and bikes with material C tended to have a different, but distinct vibration spectrum, that would at least prove to me that there is a significant difference between A and C... something I suspect is not true.

It might be possible, with another study, to equate vibration data to comfort. The only way I could think of doing this would be some kind of blind frame test - disguised and instrumented frames. After the rider rides for a few hundred miles, he rates the ride quality of the frame without knowing its brand or material. Then, the scientist can attempt to correlate the data to the subjective ride quality...

If you're doing blind frame tests, you could skip the instrumentation, but then you'd miss out on an opportunity to learn something.

There is no logic behind the debate.

Your accelerometers will just prefer whippy frames.

People always compare bikes with different wheels and tires, and claim a difference.

Give 100 men a sugar pill shaped like a blue diamond, ...30 of them will get a woody.

But that is exactly the subject of this discussion. In fact, it was proposed that it would be "easy" and "simple."

Is this a 'yes' or a 'no' to my question?

Only if the rider comments prefer whippy frames as well. The accelerometers would be a measuring device, not judge and jury. The qualitative part of the study would still be based on a rider's preference.

Keep in mind, I've stated that measuring the exact influence of material alone would be a waste of time. Measuring the influence of ride quality based on frame design as a whole would be a relatively straight-forward project and certainly less complicated than the exact same job on a motorcycle or car. Having said that, motorcycles and cars undergo this type of testing regularly.

I've said a lot of similar things to what Sheldon wrote earlier in this thread. The metallic materials that are commonly used to build bikes have essentially no damping qualities. I'm skeptical on the actual damping properties of carbon fiber, but for the time being let's leave it out of the equation.

Geometry plays a huge role in ride quality. That's exactly the point. Things like seat and head tube angles are primary players. How far do we go with the geometric influence, though? I would argue that the geometry of each individual tube is important and the material that is chosen has a large influence on tubing geometry. How these components work together as a single cohesive piece is key to understanding what produces the best ride qualities. Taking measurements to quantify what is preferred is a logical progression of this thinking.

This still means it comes down to opinion, not science.
People have a broad range of ride preferences, and I'm not convinced there are as many differences as people think.

Put the same accelerometers on a single frame, you may have a way to rate tires and wheels.

why use outside items in the experiment at all? if you want to test the frame material, then you should use only the frame.
setup a jig that holds a frame on a vibration table and take your measreuements and then simply plug in the next frame when your done.

pretty simple test if all you want to do is get vibration results.

Part 1: There is an area of study that is the subjective responses of the human body to vibratory motion. Define it as opinion or science if you want. That's a separate debate. You essentially end up with a graph of vibration frequency vs. vibration amplitude. People tolerate more amplitude if the frequency is lower, and less amplitude as the frequency increases. There are several levels of response that vary from 'perceptbile' to 'disagreeable' to 'intolerable'.

It is entirely possible that the ride preferences due to frame design are small to the point of vanishing. I've ridden bikes that would make me question your hypothesis, but I'm willing to accept it as a starting point. If that is the case, then it is worth finding out. At that point a manufacturer knows they can build the frame any way they want to and worry about optimizing other aspects of the design while not having to sacrifice ride quality.

Part 2: Instrumenting a frame and testing a variety of tires and/or wheels would also be an interesting project, and completely worthwhile to a manufacturer IMO. So if that is a worth study, why is it such a stretch to leave the wheels/tires constant and swap frames?

Have a look.

http://www.youtube.com/watch?v=LmoEc...eature=related

It's exactly what's going on here. You couldn't do it in a jig. it would have to have the rider on it (for proper weight) and have the wheels and tires on it, because they're a big part of the equation. Having said that, it's a completely valid approach.

Ultimately, though, it might be more expensive to take this approach.

I think whoever taught you guys statistics and the scientific method should be tarred and feathered, and run out of town on rails. :eek:

You're forgiven if you slept through that part of the class. It's understandable...

Your remedial homework before next class is to define the following terms: independent variable, dependent variable, reliability and validity

For extra credit, compare and contrast "statistically significant differences" and "meaningful differences" in measurements.

;)

I don't know if this is pointed towards me, but I agree with you. We just haven't gotten to this point in the conversation.

The conversation should have STARTED with this notion: is it possible to quantify the differences in materials characteristics such that we could predict differences in perceived ride quality? The answer is "no", btw.

Instead, this topic started with an arrogant insult to all of bf, an ironic slam on all the "opinions" and "lack of data", and then followed by a painful mangling of well-established investigatory methods in the pursuit of a gilded lily.

God, I love this place! :D

FWIW, I doubt there are trained professional "bicycle butts" who evaluate differences in frame materials. I think bike designers and builders consider materials available to them (and what would sell), and make what they like, check it out with their friends, run it by a pro bike rider of three, then hand it over to the marketing dept., in some order or another. Or to put it another way, "this ain't rocket surgery!" :thumb:

My guess is that they go for a certain handling characteristic, which can be predicted to a pretty high level, then they let the team riders try it out, make a few changes, and you have a bike.

The version released to the paying public is just a modified version based on production costs and what "bling" is big at the moment.

accelerometers or strain gauges?

Lol, you're looking for the Metrigear Vector thread...

Well, how kind of you to bestow your greatness upon us. It's a shame you didn't show up 5 pages ago and put this little question to rest earlier.


So, using a layman's approach to accomplish the same goal in a completely unscientific manner should somehow be preferred? You realize, of course, that there's more scientific approaches to coffee bean roasting than what you propose.

Interesting read:

http://web.mit.edu/2.tha/www/ppt/Bike-ISEA.pdf

http://cozybeehive.blogspot.com/2008...s-by-vlus.html

comments?

Good read! :thumb:

I'll accept a certain amount of snarkiness in return, no probem! ;) I wasn't criticizing you, really the OP's whole first post. He was miffed about the lack of "scientific analysis" yet has nothing to offer except more opinion.

Sure, plenty of research involves operationalizing difficult to quantify variables, which is all you have when you're trying to assess (and predict) "ride quality". That's why more rigorous methodology is essential in research design, to make sure you're close to measuring what you say you are.

I like your reference, btw, about the coffee bean roasting. Just like with bike design, you can easily quantify and control many elements of the roasting process. Just don't confuse that with making good coffee.

It's an order of magnitude more difficult to find reliable and valid measures of "good coffee". Just like with bikes, give a hundred people the same cup of coffee, and you're going to get a very wide range of responses when you ask them how they like it.

Bike designers and builders are obviously in the ball park with what they make, so they must be on to something with the materials they use and how they use them. I just don't think anyone can build a bike that pleases everyone who rides it. This suggests that, in the end, it's still subjective and impossible to predict with any certainty what will create a "good ride".

/rambling

You do know that there are professional tasters that work for coffee companies, though, right? There opinions dictate what gets produced and how it's produced. Same deal with tea. Lipton, for instance, is very scientific in their approach and their taster's opinion is also backed up by chemical analysis of the final product. It's not unlike what we've proposed here.

While I agree that it would be completely impossible to create a bike that would be all things to all people, I don't think that would ever be the goal. The goal would be to produce the bike that would be most likely to be purchased by the market segment you're going for. Ride characteristics would be one part of appealing to that market segment.

Did you check out the links? It's at least good food for thought. Maybe something to read over a good coffee or tea.

interesting how the use of vocabulary expands when trying to show superior mental power over one another.

i like to speak like an idiot cause its easier to get my point across.

basically who cares what its made out of. ride what feels comfortable to you. take into account what people recommend, but make sure you put your derriere on the bike.

there are differences in a materials ability to dissipate vibration, but nothing you could honestly feel.

but of course someone will come along and try to trump my post, with fancy words. so i will end on this, its all about the wheels.

And wheelbase and fork rake have nothing to do with it? (were those words too fancy?)

haha. your smart. no they weren't too fancy but your lack of reading any of my previous posts shows that your just trying to start crap.
I will sum it up for you, i posted... for a frame, it comes down to geometry, not material choice.
i believe that wheels are more important than any of that when it comes to changing the way a bike feels over anything else you can do. if you disagree with that, well do some R&D. Its easy to jump into a thread and talk it up. just look a page or two back and you will see i posted exactly what you said also.

Research Protocol:
1) Literature review.
...

thanks, that post helped