Road bike vs. recumbent comparison

[Osiris]

Now there, a failed replication does not equal falsification and you know that.

Actually, it does prove that. That's how the principle of falsification works. What you are claiming is that trplays experiment did not replicate what happens when applying the bar wagging technique. You want us to believe that because trplay didn't get the result you thought he would, this must mean that he didn't perform the experiment correctly. What's your evidence of that?

Absence of evidence is not evidence of absence.

This is one of those examples of "folk wisdom" that people commonly endorse without understanding what they're actually saying. At best, it only applies to unfalsifiable claims. An unfalsifiable claim is one which cannot, even in theory, be disproved. For example, how would you disprove the claim: "Somewhere in the universe there are unicorns"? Plainly, you can't. The fact that we have no evidence that unicorns exist any place we've looked doesn't mean that unicorns don't exist in some other place we haven't looked. But if someone were to claim instead that: "There are unicorns in Scotland", then our failure to find any unicorns in Scotland would indeed falsify the claim.

The claim about handlebar wagging resulting in a greater power output is not unfalsifiable. It has been tested and falsified. The only objection left to you is to say that the test was somehow invalid, but you haven't given us any reason to conclude that.

I kind of afraid of testing boom swinging on my FS MBB "all the way" because wallmart bike pivots are known for developing play without subjecting them to huge twisting loads even, but what I do *seems* efficient and give me a bit of extra power.

The important word here is "seems". You think it works, but you have no hard evidence of that. Not long ago, I had a disagreement with another local bent rider who assured me that pulling back on the handlebars of her Bacchetta produced extra power. She insisted that she would not have been able to climb very steep hills if she hadn't been using this technique. She seemed so sure of this that I decided to test it on my own Bacchetta. Sure enough, pulling back on the handlebars does produce the sensation that you're putting out more power, but are you really? Not according to my power meter. No matter how many times I repeated the experiment, there was no measurable difference at all between pulling and not pulling on the handlebars. I pointed this out to her, but she was so convinced that her belief was true that nothing I said was going to convince her otherwise. But as luck would have it, she and I happen to use the same style of pedals, so it was a simple matter to put my Garmin Vector power meter on her Bacchetta and let her see for herself. You can guess the result: the increase in power she thought was there proved to be completely illusory. This is why I don't believe dubious claims not backed up by hard evidence. It's not that I think the people making these claims are consciously lying; it's just that I've seen time and time again that it takes almost no effort for people to convince themselves of something that just isn't true.

 

[Balor]

What's your evidence of that?

Because there is WAY too much variables in the mix. Humans are not engines that produce equal amounts of power for a given press of a gas pedal.
Again, for *me*, the principle is sound, though not everyone does it even it DF bikes where it should work *much* better than on Cruzbikes due to leverage.

Would you consider one case of someone *claiming* that they produce more power by boom-waggling to be a conclusive proof? No way, you'd say something about placebo effect and whatnot. You'll be right, too.
We need much more data before the issue would be completely settled.

This is why I don't believe dubious claims not backed up by hard evidence.

My point exactly. One data point is not evidence.

 

[Osiris]

Because there is WAY too much variables in the mix. Humans are not engines that produce equal amounts of power for a given press of a gas pedal.

But I asked you what evidence you had that trplay didn't perform the experiment correctly. You didn't answer that. You now opine that his negative result can be attributed to some unspecified variables. You have no evidence for that either.
Let's remember what the claim being tested actually is. Ed72 estimated that waggling the handlebars would net anywhere from a 15-20% power gain. Jim's test shows the power gains to be far higher than even Ed72 surmised. These are not "minor" gains. If there was any truth to them, it would be instantly recognizable on a power meter. Yet even someone as admittedly biased as trplay, despite several attempts, could not find ANY difference in power production. That's not something you can explain away without making additional assumptions. And for those assumptions to have any weight, you need to provide evidence that they're true. So essentially what you want to do is to write a check on an account in which you've made no deposit.

Would you consider one case of someone *claiming* that they produce more power by boom-waggling to be a conclusive proof? No way, you'd say something about placebo effect and whatnot. You'll be right, too.

That's actually not what I'd say. First, I would take a close look at how the experiment had been performed to determine whether the methodology is valid. Then I'd ask myself whether the person performing the test may have a clear bias toward obtaining a certain result. Then I'd look at what the difference actually amounted to and see what could be gleaned from that. If the difference was very small, I'd probably conclude that the case had not been adequately proved. If the difference was unusually large, say in the neighborhood of hundreds of watts, then I would find those numbers highly suspicious. trplay's report raised none of these concerns, whereas Jim's raised all of them.

My point exactly. One data point is not evidence.

If by "data point" you mean test, then of course one test is evidence. It may not be evidence sufficient to convince someone determined to believe otherwise, but it is nonetheless evidence. And the less likely it is that the result may have been contaminated by unanticipated variables, the stronger it is as evidence. Contrary to what you've said, some claims are so easy to test that all it requires is one test to conclusively disprove them.

 

[Balor]

Contrary to what you've said, some claims are so easy to test that all it requires is one test to conclusively disprove them.

Unfortunately, that is NOT one of them. Again, we are talking biomechanics here - if you think that ANYTHING regarding it is simple, you are, frankly, wrong. So long as we don't have a comprehensive model of what is going on when you pedal on a bent down to most basic components, there is always room for 'unanticipated variables'.

For *ME*, one test (the 'string' test you were so quick to dismiss) was enough to prove that there MAY be some merit to those claims, because dynamically changing seat to pedal distance during pedalling might have profound effects (that is basically opposite of having, say, a flexy seat back - and I dare you to say that it does not matter at all!).

Currently, I'm taking a position of a militant agnostic - I don't know, and neither are you . I am really not vested in any side of the debate - I'm devoted more to MBBs in general than Cruzbikes in particular (though I find them the best of currently mass-produced designs to be sure... not there is much, to be fair), and just like for you, the gains are of the more obvious sort - short, stiff and easy to maintain drivetrain, no heel strike and particularly ability to have low BB and large front wheel.

We do need more data - and that should come in form of a at least several experienced Vendetta riders doing several hill repeats while trying and not trying to wag the boom as much as possible, with HR, speed and power being monitored. Some homebuilders with no particular stake in either outcome can be recruited as well for instance - but it has to be 'cruzbike clones', because Flevos and Pythons will not work at all for obvious reasons, and French designs are not much better.
Like I said, my MBBs (one with shortest boom in particular) should actually be better at it, but I don't have PM yet and even climbing/sprinting PRs don't show much because my power output is, unfortunately, highly inconsistent... but I'll try that eventually.

 

[Osiris]

Unfortunately, that is NOT one of them. Again, we are talking biomechanics here - if you think that ANYTHING regarding it is simple, you are, frankly, wrong.

I didn't suggest that the biomechanics of climbing on a Cruzbike are simple. I was merely correcting you when you declared that, "one data point is not evidence". It absolutely IS evidence. Perhaps you're just confusing the word "evidence" with the word "proof". They're not the same thing.

So long as we don't have a comprehensive model of what is going on when you pedal on a bent down to most basic components, there is always room for 'unanticipated variables'.

But you can't tell me which of these 'unanticipated variables' invalidates trplay's negative result. All you're doing is trying to muddy the waters to avoid the conclusion you don't like. Why do I think that? Because you weren't even slightly critical of Jim Parker's experiment, when you should have been. All your criticism has been directed at trplay's experiment, which was a far better and more believable one than Jim's.

For *ME*, one test (the 'string' test you were so quick to dismiss) was enough to prove that there MAY be some merit to those claims, because dynamically changing seat to pedal distance during pedalling might have profound effects.

Yes, like a loss in power due to pedal steer. Did you ever consider that? Whenever you pedal a MBB, some of that energy is wasted in the form of unwanted boom movement. You can try to counteract that by tugging on the opposite handlebar, but you will never be able to eliminate ALL boom movement. Some pedaling power will necessarily be lost, just as it is due to a flexible seat or your own example of tissue hysteresis.

Currently, I'm taking a position of a militant agnostic - I don't know, and neither are you . I am really not vested in any side of the debate.

Of course you are. You're already made clear your unshakable certainty that handlebar wagging increases power output: "Boom swinging, however, MUST work, but I'm simply unsure on extent of this effect, especially on Cruzbike with long boom and short tiller." Your own words indicate that you are not an agnostic Balor; you are a true believer.

We do need more data - and that should come in form of a at least several experienced Vendetta riders doing several hill repeats while trying and not trying to wag the boom as much as possible, with HR, speed and power being monitored.

More experiments would certainly be welcome, although I think doing them on a swiveling trainer like trplay did is a better testing methodology. It allows the test subject to concentrate much better on what he's doing, and it is immune to inconsistencies due to different road surfaces, traffic conditions, and anything else that might distract the test subject.

 

[Balor]

It absolutely IS evidence. Perhaps you're just confusing the word "evidence" with the word "proof". They're not the same thing.

Hmm, ok, you are right here. But so long as we are talking semantics, it has nothing to do with definite 'falsification' either.

. Why do I think that? Because you weren't even slightly critical of Jim Parker's experiment, when you should have been.

Your own words indicate that you are not an agnostic Balor; you are a true believer.

I've been quite critical of 'bar pulling' before for exactly same reasons that you are. But now maybe, just maybe, I understand the underlying principles better than you do? There is a difference between knowledge and belief.

Yes, like a loss in power due to pedal steer. Did you ever consider that? Whenever you pedal a MBB, some of that energy is wasted in the form of unwanted boom movement. You can try to counteract that by tugging on the opposite handlebar, but you will never be able to eliminate ALL boom movement. Some pedaling power will necessarily be lost, just as it is due to a flexible seat or your own example of tissue hysteresis.

And I think you simply don't understand it, because what you say is absolutely wrong. First, you absolutely can. Next, your 'boom swinging', just like I said (and you ignored) is opposite to 'boom waggling' or seat (or flesh for that matter) flexing that happen on other bents. At the very least, you can *compensate* for that flex (boom, flesh and seat combined), and at most - actually decrease your seat-to-pedal distance instead of vice versa!
Come to think of it, that might be the main culprit of my losses, not *hysteresis* per se - and those losses are basically a percentage of power stroke wasted in flesh/seat/padding flex... but I need to wrap my head around that one myself.

More experiments would certainly be welcome, although I think doing them on a swiveling trainer like trplay did is a better testing methodology. It allows the test subject to concentrate much better on what he's doing, and it is immune to inconsistencies due to different road surfaces, traffic conditions, and anything else that might distract the test subject.

That is true, though using a trainer might add some confounding variables of it's own into the mix (for instance, like I said I've actually tried that and it is REALLY awkward - though my trainer had no tilting functionality) and asking a lot of people to replicate his setup is unrealistic.

 

[Osiris]

Hmm, ok, you are right here. But so long as we are talking semantics, it has nothing to do with definite 'falsification' either.

The word 'falsify' doesn't refer only to conclusive disproof. Notice the words it's synonymous with:
synonyms: disprove, refute, debunk, negate, negative, invalidate, contradict, controvert, confound, demolish, discredit

I've been quite critical of 'bar pulling' before for exactly same reasons that you are.

If you are certain that bar pulling "MUST" work, then you are anything but agnostic about it. I've never once seen you express any doubts as to whether bar pulling works, only the certainty that it does.

And I think you simply don't understand it, because what you say is absolutely wrong. First, you absolutely can. Next, your 'boom swinging', just like I said (and you ignored) is opposite to 'boom waggling' or seat (or flesh for that matter) flexing that happen on other bents. At the very least, you can *compensate* for that flex

What you're talking about is actually a case of over-compensating for pedal steer. Even if it were possible to apply precisely the amount of force necessary to prevent the boom from moving in response to pedals steer, which no one can do consistently, if at all, you are using upper body muscles to do it. You are expending energy that you wouldn't need to expend when riding a bent with a fixed boom. Why do you think racing recumbents have the stiffest frames? Because stiff frames result in the least amount of energy lost through unwanted flexing.

That is true, though using a trainer might add some confounding variables of it's own into the mix (for instance, like I said I've actually tried that and it is REALLY awkward - though my trainer had no tilting functionality) and asking a lot of people to replicate his setup is unrealistic.

If getting more test subjects is the only consideration, then doing a road test will accomplish that. But if getting a result free of a number of contaminating variables you're likely to encounter on the road is the object, then the swiveling trainer would be preferable. The problem will be overcoming people's unwillingness to accept negative results. No matter how many tests are performed, the Cruzbike faithful who are certain that handlebar pulling works will always insist that the test just wasn't done properly.

 

[benphyr]

Is there a way to block certain threads and/or posters from showing up in one's "new posts"?

I love to read the kind of awesome help-each-other-out type posts that make the tribe great without getting bogged down wading though this sparring.

The topic is great, it has just become seriously bogged down in continuous negative criticism.

I agree that I disagree with the atmosphere this thread has become.

 

[Gary123]

Second that

 

[Don1]

well. i went on a ride on my df (it was sad) after 9months of exculsive mmb riding. found a route that is trying that i hsd done recently... 42km 700m climbing. first thing i noticed was how high i was and a fear the i'd go over the bars at any moment.lol.

anyways. moving along found on the false flats i was 25bpm heart rate higher and 12kmh slower. come to the hills and df shows off being 7kg lighter. pick a gear and power surges to the road. on mmb due to weight too far back spins the whèels bout 2kmr slower up hill. down hill the df is crruently faster since it feels natural compared to still finding confidence on the mmb, that'll change. through traffic i found it easier to navigate with mrrors than constantly contorting your head on a df. the garmin is very loud and up coming cars are more noticeable over wind noise on mmb. i get waves and thumbs up on a mmb, conpletely oblivious on df. chafing on the inner thighs was unusual exprience on the df anyway after everything else started hurting that didnt bother too much. oh 22.9 av on df 22.7 on mmb (due to slow down hill confidence. i enjoyed the weight to power of the df now i want the same on mmb.... no3 on the drawing board.

 

[ak-tux]

well. i went on a ride on my df ...

... anyways. moving along found on the false flats i was 25bpm heart rate higher and 12kmh slower. come to the hills and df shows off being 7kg lighter.

.. ..oh 22.9 av on df 22.7 on mmb (due to slow down hill confidence. i enjoyed the weight to power of the df now i want the same on mmb.... no3 on the drawing board.

+1
Once the MBB is perfectly dialed in, the only difference, to me, really (with the exception of traction on extreme grades) is the weight in favour of the DF. My DIY MBB, out performs my DF on rolling terrains even if my DF is lighter by 6Kgs!

 

[Balor]

I agree that I disagree with the atmosphere this thread has become.

You don't have to be OCD to enjoy it, but it helps (~c). I kind of do, and I'm sure Osiris is having a blast . You cannot have truth without argument with conflicting theories, and I daresay what we have is pretty civil (though admittedly a bit less than I'd like). I can totally understand his POV, but I do like to keep my mind a bit more open so long as there is not enough conclusive evidence either way.

The word 'falsify' doesn't refer only to conclusive disproof.

English not being my primary language (entirely self-taught to boot) I can mix words, so please bear with me (with me being a Russian, it also will make me feel more at home ).

If you are certain that bar pulling "MUST" work, then you are anything but agnostic about it. I've never once seen you express any doubts as to whether bar pulling works, only the certainty that it does.

Let's put it this way. *mere* bar pulling 'works' in a way that it provides alternative to bracing against the seat. Whether you derive any benefit will greatly depend on how seat-bracing works for you. I can totally see that for a lot of people, bar pulling will actually be less effective, but my case is pretty severe.

What you're talking about is actually a case of over-compensating for pedal steer.

Yes, that is EXACTLY what 'boom swinging' is about in technique.

You are expending energy that you wouldn't need to expend when riding a bent with a fixed boom. Why do you think racing recumbents have the stiffest frames? Because stiff frames result in the least amount of energy lost through unwanted flexing.

Of course, you are getting less *efficiency* (watt per calorie) with boom-swinging (or bar-pulling), I do not deny that. But you are getting more power *to the pedals*. Just like with standing sprints to victory SOME riders do on DF, so is with boom swinging - cannot be maintained for long, but allows higher max power at the cost of mechanical efficiency.

Very fast cadences (alternative method) are not dissimilar in that way - you are getting a huge drop in mechanical efficiency due to internal friction in your own muscles contracting with very fast speeds.

Basically, unless you sign under Heine 'planing' theories (and them being applicable to a bent in particular), you must either agree that either stiff frames don't matter, or boom swinging work, because boom swinging is basically having a frame with more than 100% stiffness, and if you lose power with a frame that is not 100% stiff, you ARE getting extra power with boom swinging.
Of course, having a frame that is, say, 99% stiff vs 90% stiff on a fixed boom bent will result in some 'free' gains in power, and 'boom swing overdrive' require upper body involvement.
Yet, for sprint efforts where you can run into huge oxygen debt with impunity it WILL work... that also work with 'hill surfing', where you sprint up the hill followed by coasting downhill. That is why Ed is so interested in Vendetta performance - PBP is full of rolling hills and a LOT of time might be gained by perfecting the technique.

 

[Osiris]

English not being my primary language (entirely self-taught to boot) I can mix words, so please bear with me (with me being a Russian, it also will make me feel more at home ).

Don't worry about it. English is actually my fourth language. I tried to teach myself Russian long ago, but found it much, much too difficult.

Of course, you are getting less *efficiency* (watt per calorie) with boom-swinging (or bar-pulling), I do not deny that. But you are getting more power *to the pedals*.

I'll remind you again that this is just your opinion. You have no objective evidence for it. The only objective evidence from a reliable source so far was supplied by trplay, and his results show that waggling the bars accomplished nothing (other than wasting energy). If you want to convince me that waggling the handlebars does what you think it does, you'll have to do a lot better than just repeating the same claim over and over again. You will have to demonstrate that trplay's result was either false or inconclusive. Then you'll have to present the results of another test (or series of tests) that support your thesis. You haven't done either of those things.

boom swinging is basically having a frame with more than 100% stiffness, and if you lose power with a frame that is not 100% stiff, you ARE getting extra power with boom swinging.

Again, that's just your belief, unsupported by objective evidence. Furthermore, there is a difference between conserving energy by making the frame as stiff as possible and using your muscles to compensate for the lack of stiffness. In the former case you are not expending any energy; in the latter case you are.

Yet, for sprint efforts where you can run into huge oxygen debt with impunity it WILL work...

Let's pretend that this is actually true, and ask a common sense question. If an MBB worked as you think it does, then why are custom designers like John Morciglio and Thomas Ohlinger, both of whom have designed and built MBB recumbents, using fixed boom recumbents to set world sprint records? They can build and race anything they want, so why not capitalize on the extra power you say MBB's are capable of producing to win sprint races? Surely it would be in their interest and their customer's interests to do so, right?

 

[Balor]

I'll remind you again that this is just your opinion.

You don't need to, I know that already. My only "strong" claim is that, unlike 'mere' bar-pulling, boom-swinging or 'pedal feedback overcompensation' seems like a method of actually delivering upper body power into the cranks that can really WORK. I'm just asking for more data whether magnitude of this effect is measureable. It might not and I'm ready to accept that.

The only objective evidence from a reliable source so far was supplied by trplay, and his results show that waggling the bars accomplished nothing (other than wasting energy)

... and you didn't ask for power meter data, discussed testing procedures, etc - his results agreed with your assumptions and you were quick to latch to them as 'objective evidence from a reliable source'. Bias blind spot much?
After all, we already have data from Jim and while I agree that he has vested interests outright dismissing him without any consideration is tantamount of calling him a fraud.

If an MBB worked as you think it does, then why are custom designers like John Morciglio and Thomas Ohlinger, both of whom have designed and built MBB recumbents, using fixed boom recumbents to set all the world sprint records? They can build and race anything they want, so why not capitalize on the extra power you say MBB's are capable of producing to win sprint races?

Because, sans fairings (and I'm currently up to my ears in CFD addressing this very problem) MBB formfactor with it's need for wider bars (and the wider - the better for sprinting they would be!) is not entirely conducive to superior aerodynamics and unless those are uphill sprints, even Chris Hoy will not outsprint an elderly gentleman in a nearly 3x heavier Milan velomobile, and I'm not even talking about streamliners like Eta, and you *know* that, so why do you even ask?

 

[Balor]

Heh, talking of testing magnitude and 'bad aerodynamics'

How about attaching a set of MTB DH bars to Vendetta (so long as it is on the trainer) and trying 'boom swinging' using those?
If any effect would be unmeasureable than, I'll be ready to admit that 'boom swinging', at least on Vendetta, is only 'placebo effect'.

I'll want a video in action, though, if only for the sight of it!

 

[Osiris]

Back to the subject of comparing a DF to a recumbent. Last weekend I continued performing some tests to see if I could determine in which circumstances my DF has a significant performance advantage over my V20 (or any other bent I've owned). The DF allows me to produce much more peak power than I can on any bent; about 200 watts more. The disadvantage of course is that the DF is a dog when it comes to aerodynamic efficiency. It's like dragging a parachute behind me, so all that extra power doesn't translate into anything useful, except on extremely steep climbs where aerodynamics is negligible.

There are a couple of long uphill segments that I use for testing purposes, but the slope on both is pretty gentle (about 1-2%). My PR on one of them is something in the neighborhood of 26 mph average on my M5. My best on the V20 has been around 25 mph average. What I usually do instead of paying attention to speed is to see how long I can hold a certain wattage. I usually aim for 300W, which gets me most of the way to the top before exhaustion sets in. On the DF, I was absolutely crushing my usual wattage numbers last Sunday. I started with something like 600W and almost made it all the way to the top of the hill without going below 300W. But even with a much higher power output, my speed was nowhere near what I can manage on a bent. Since it took me significantly longer to get to the top, it meant that I was also expending more energy to cover the same distance just fighting gravity. There's just no getting around the fact that DF's are terrible designs when it comes to efficiency. It's very disheartening to have to work so hard for so little, but it does make me appreciate my bents so much more when I ride them.

 

[ed72]

You don't have to be OCD to enjoy it, but it helps (~c). I kind of do, and I'm sure Osiris is having a blast . You cannot have truth without argument with conflicting theories, and I daresay what we have is pretty civil (though admittedly a bit less than I'd like). I can totally understand his POV, but I do like to keep my mind a bit more open so long as there is not enough conclusive evidence either way.


English not being my primary language (entirely self-taught to boot) I can mix words, so please bear with me (with me being a Russian, it also will make me feel more at home ).



Let's put it this way. *mere* bar pulling 'works' in a way that it provides alternative to bracing against the seat. Whether you derive any benefit will greatly depend on how seat-bracing works for you. I can totally see that for a lot of people, bar pulling will actually be less effective, but my case is pretty severe.



Yes, that is EXACTLY what 'boom swinging' is about in technique.



Of course, you are getting less *efficiency* (watt per calorie) with boom-swinging (or bar-pulling), I do not deny that. But you are getting more power *to the pedals*. Just like with standing sprints to victory SOME riders do on DF, so is with boom swinging - cannot be maintained for long, but allows higher max power at the cost of mechanical efficiency.

Very fast cadences (alternative method) are not dissimilar in that way - you are getting a huge drop in mechanical efficiency due to internal friction in your own muscles contracting with very fast speeds.

Basically, unless you sign under Heine 'planing' theories (and them being applicable to a bent in particular), you must either agree that either stiff frames don't matter, or boom swinging work, because boom swinging is basically having a frame with more than 100% stiffness, and if you lose power with a frame that is not 100% stiff, you ARE getting extra power with boom swinging.
Of course, having a frame that is, say, 99% stiff vs 90% stiff on a fixed boom bent will result in some 'free' gains in power, and 'boom swing overdrive' require upper body involvement.
Yet, for sprint efforts where you can run into huge oxygen debt with impunity it WILL work... that also work with 'hill surfing', where you sprint up the hill followed by coasting downhill. That is why Ed is so interested in Vendetta performance - PBP is full of rolling hills and a LOT of time might be gained by perfecting the technique.

Exactly.

I had planned to go under 50 hours at 60 years old on my DF, that was before my medical issues popped up.

I still want to go as fast as possible. Maybe under 56:40 time.

Did anyone look at the Pantani video.

Anytime a DF racer wants to accelerate, they get out of the saddle and engage the upper body. For me it is second nature to get out of the saddle when approaching a switchback in the Alps or other high mountains. At the corner the effective gradient is very high and the extra power is needed.

When I did the UMCA National race with Larry, Jim, and Will, there were a lot of corners. All three had a significant advantage on me coming out of them. This is not theory. It is direct observation. As I noted earlier, I've done some criterium racing on DFs and keeping up out of corners wasn't much of a problem. Maybe my guesstimate of 15-20% was high.

Sorry to interrupt your fun.

 

[Osiris]

You don't need to, I know that already. My only "strong" claim is that, unlike 'mere' bar-pulling, boom-swinging or 'pedal feedback overcompensation' seems like a method of actually delivering upper body power into the cranks that can really WORK. I'm just asking for more data whether magnitude of this effect is measureable. It might not and I'm ready to accept that.

Well, I suspect I'll be waiting a very long time, but let me know when you've got something.

... and you didn't ask for power meter data, discussed testing procedures, etc - his results agreed with your assumptions and you were quick to latch to them as 'objective evidence from a reliable source'. Bias blind spot much?
After all, we already have data from Jim and while I agree that he has vested interests outright dismissing him without any consideration is tantamount of calling him a fraud.

First of all, power meter data is irrelevant because trplay himself said that the numbers were the same in both cases. So it wouldn't matter whether he was putting out 300 watts or 600 watts in his experiments; the fact remains that he saw no difference when applying the handlebar waggling technique. As for the testing procedure, you've already seen the setup he used in his video. What more do you need to know? As for trplay's reliability, have you read his blog? He makes no effort to conceal his pro Cruzbike bias. He even mentioned it when posting his results. When someone as clearly biased as he is to see a positive result doesn't get one despite his bias, I have even more reason to trust his results than if the test had been performed by a disinterested party. Jim admits that as a company owner, he has not just a personal bias in the outcome, but a financial stake as well. That's one reason for me to be suspicious. The second reason for my suspicion comes from looking at his numbers. Did you see them? Did you notice how unnaturally low his power outputs were when he wasn't using the bar waggling technique? There is no reason someone as large as Jim and as well trained as he is on a bent would produce such low numbers. It doesn't make any sense. Not unless he was doing precisely what he suggested, namely, that he was "conciously or unconciously" biasing the test results. So no, I didn't dismiss his test without any consideration. In fact, I considered the matter much more carefully than it would appear you did.

Because, sans fairings (and I'm currently up to my ears in CFD addressing this very problem) MBB formfactor with it's need for wider bars (and the wider - the better for sprinting they would be!) is not entirely conducive to superior aerodynamics and unless those are uphill sprints, even Chris Hoy will not outsprint an elderly gentleman in a nearly 3x heavier Milan velomobile, and I'm not even talking about streamliners like Eta, and you *know* that, so why do you even ask?

Well, we may at last have a point of agreement. An MBB just isn't a suitable design for sprint racing, even if you think you can get significantly more power out of one. I'm sure one of the Cruzbike faithful will be along any minute to disagree...

 

[Balor]

There is no reason someone as large as Jim and as well trained as he is on a bent would produce such low numbers. It doesn't make any sense.

Well, I don't know. It made no sense to me why I'm 2x times slower on (RWD) bent either! Again, so long as we are talking biomechanics, few things are simple and straightforward (and work equally for everyone!).

You cannot deny that LWB bents like tour easy are absolute aerodynamic pigs (weight and size wise, too), but a lot of people love them.
Remember my link about Fred Markham's results using socked Javeling?
Well, I think I'm onto something here, stay tuned .

 

[ed72]

Balor.....just make a nose cone.

For the record, I thought Jim's power levels during the demonstration were quite reasonable for road racing purposes.

How many degrees of freedom are associated with pedaling a bike, the biomechanics are very complicated.

Until I switched to the Rotor RS4X crankset, my legs (especially the left) would have extreme localized soreness and pain after a ride. This is not normal. One should be able to hammer all day long and not have such pain. It was obviously a biomechnical issue that I had never had on an upright. Switching the crankset now allows me to ride as hard as I want without those local quad pains. The first 10-15 degrees over the top of the stroke are now without resistance. In a similar way, a DF rider slight moves the pelvis and ankles the foot when pedaling over the top of the stroke. The advantage is rotational, not translational. There are a lot of moving parts and it is not so simple as words. I think I mentioned Ed Sassler (Harvard cycling coach) earlier and his pedaling approach to climbing. Most forum warriors wouldn't believe it would help. I diligently applied what he was in his educational videos and gained a fairly significant increase (more than 10%) in climbing power.