Originally Posted by Campag4life

Conflate much? Because I posted a link showing CFD which is used as an analytical tool commonly across industry? That's silly.

Not precisely sure how R Chung's model crunches CdA but pretty sure this value is 'backed out' of the algorithm due to measurable variables like Power, speed and time and other model assumptions. The problem is, there is error in each variable which is cumulative and because of variables like wind and rolling resistance, the error in these numbers obfuscates true contribution to any change in CdA...say in riding position or bike frame shape or benefit of skin suit or helmet shape etc. This is only my opinion. R Chung's model iterates this error out...or tries to, to create a more 'honest' CdA value. The tool may or may not have value. There are a couple of guys here that loosely understand how the model works like Dave and wphamilton because of their education. I am sure most that use it don't have R Chung's math background and if he is a PhD in math I don't either.

Maybe time to summarize this thread. There really shouldn't be any advice from guys with no experience with R Chung's model, the guys here who watch a video and decree its the greatest revelation since sliced bread. That pretty much eliminates about 3/4's of the bickering in this thread. I believe its OK to ask about it or maybe even suggest why it may not be accurate like I have even though that may not be fair either...but because of my training, I am skeptical at least. There has been stalwart support for R Chung's model which I believe is without foundation because those passing judgement probably don't have graduate level training in science and math. So all the poseurs here which are the usual cast of characters who are looking to be critical of others for some need for oneupmanship when people question the model, that is simply absurd. It is OK to question it. A lack of succinct explanation of how it works by its creator of course brings into question its veracity which of course promotes more questions. I believe the reason and again could be wrong that R Chung isn't more forthcoming or more succinct is because this would bring out more opposition because the predicate of how his algorithm works would be further challenged. You know...the part where R Chung says...he 'takes on data sets which known holes in the data' that other scientists won't touch. This is a fundamental disagreement between scientists. This is because R Chung makes assumptions which many believe to be too fraught with error. In other words, what he is trying to do with his algorithm is bogus or minute changes in CdA that he is trying to glean with his model are lost in error. He makes his model work by filling in the blanks of uncertainty...but problem is, there is too much noise in his data set. Only my opinion. Maybe if change in CdA is blatant enough...error is subordinate to magnitude of real change. As an example a rider going around a flat windless course changes his torso angle in 1 degree increments while maintaining the same steady state watt output.. Most know the rider accounts for about 80% of CdA. The error in R Chung's model may not pick up a 1 degree change in riding position. Or, change in speed maybe lost in measurement and normalization of watt output or windage change. It may, but may not. But, his model may pick up a change of 10 degree torso angle because now magnitude of CdA has changed enough to be recognized by the model. But this level of blatant change isn't what a racer is looking for. A racer is looking for extremely fine increments of change.

So what is a good racer really chasing? A needle in a haystack basically. A very small increment of change due to years of developing their skills. I have asked the fastest rider in my town when out on a group ride, what makes you faster? What do you work on? He said and I believe this to be dead accurate, that riding a bike fast is an equation. He tries to optimize everything contributing to speed and of course because he is so fast, he does a lot of things very well. He really understands his craft. Most successful racers do. They know what makes them fast. Aero is fast of course. I just believe that arriving at CdA the way R Chung does has questionable value. Hard to prove either way. I place much more veracity in wind tunnel testing because the environment is much more controlled thereby eliminating other variables which solve for CdA implicitly....by interpolation or extrapolation. Yes the argument is...if one isn't available, costs too much etc. My response is, if you can't afford a bike computer, putting your finger in the air to measure wind speed as a predictor of bike speed isn't very accurate either.

Originally Posted by redlude97

how cute, you've finally caught up to the rest of us. Explain again how you can hold a power to 1/4 watt and your response to this model is to use your own loop with a timer gets better results again? We all bow down to your nonracer greatness

Originally Posted by asgelle

Originally Posted by Abe_Froman

I think an important question that you should ask yourself is, "why are you here?" Is it to answer the one or 2 technical questions of the 1 or 2 people that know just a bit about the technical aspects of your work? Because all your other responses seem far closer to trolling than anything else.

Originally Posted by surak

I think an important question that you should ask yourself is, "why are you here?" Is it to ask one or 2 basic questions that have been repeatedly answered in this thread? Because all your other responses seem far closer to trolling than anything else.