Road bike vs. recumbent comparison

[McWheels]

I know it's a DF, but it's one most people could probably find at the local Y or gym. 5k on a WattBike. If you're getting in at 7 minutes then it seems to be a rough 300W average. Notwithstanding 'bent legs' [familiarity with position] might it be a useful benchmark to argue around?

 

[Osiris]

Read as much or as little as one would like into the quote above and post here. Some have already gone beyond its meaning. My goal was to ride at a consistent cadence 60/90/105 rpm , monitor the wattage then start the push pull keeping the cadence the same and see what happens. Here's what happens. Heart rate, cadence, power increases. Trying to keep my pedal stroke consistent was basically not doable. I slow down the rpm and you get a huge power drop and then a huge spike when you try to bring it up. I simply cant pedal keeping a steady cadence or wattage to get any meaningful numbers. When Connie tried it was the same yo- yo effect.

Is it possible for you to start the test with the handlebars already moving and just maintain the same cadence?

 

[trplay]

Sure, but I don't think you understand the push pull magic. One doesn't simply wiggle the bars and hold on as the bike takes off like a jet. It's a synchronization of cadence, speed, gradient , pull, sort of thing. If I started with that rythmic motion on the trainer and then stopped bar movement I am "beyond" confident the cadence and heart rate would drop along with a big power drop. To keep the cadence level would mean more power which means a spike in the numbers and a yo-yo effect which is exactly the current problem. Maybe using erg mode may help? Although I don't quite understand erg mode.

 

[ed72]

Tim Turner is below average in size and weight, but his physical conditioning is stellar. It would be more useful to compare apples to apples, don't you think? Jim is a large guy at 6'-2". That's two inches taller than I am, and I suspect he weighs in the neighborhood of 190-200 lbs. That's what Kent Polk weighs at the same height. Big guys make lots of power, even if their power to weight ratio isn't that impressive. A larger than average male younger than I am who trains regularly and participates in races should be able to put out significantly more power than I do, yet Jim's numbers don't even come close to mine. How do you explain that? By suggesting that every power meter I've ever used is off by several hundred watts? By suggesting that I'm a genetically gifted cyclist? Neither of those is even plausible, much less true. The only other explanations are that Jim's power meter is malfunctioning, or, as he himself suggested, that his bias contaminated the test results. I suspect the latter, because even someone as admittedly biased as trplay failed to find any evidence backing up Jim's test results. That's a fact I notice you've studiously ignored.



Yes, perhaps a bit less emotion and more clear thinking would be useful.



A "relatively modest 727 watts"? So what you consider "relatively modest" is already 231 watts higher than Jim's test result? Think that over for a second. You are confirming what I said about Jim's numbers being unnaturally low. If we factor in your advanced age compared to his, things look even worse for the case you're trying to make.

I am nearly 6'4' and 225 pounds. During my competitive hockey playing days thru college and beyond, I had a top notch sprint. I would also say I rarely lost a heads up sprint within my racing class. So, I am a fast twitch guy living in a slowtwitch world although after decades, my composition has undoubtedly shifted. What I confirmed was that I had trouble making getting beyond 500 watts and into 600 watts for many, many, many months. I trained specifically to increase my sprinting. Hard stuff for months one end......like Tabata intervals and much worse, the kind that make you puke your guts out. I did this grueling training 2-3 times per week. I had other reasons but won't go into it here. This is what I confirmed....my peak power was similar to Jim's values until I specifically trained to increase it. I could share my e-mails with XERT's software guys (but won't) because their mFTP algo also had problems with MY unnaturally low peak power. So, I again do not agree with your bolded and underlined statement. I am not confirming your incorrect supposition.

Did you review Jim's race history files? Do those power levels match his statements? Did you see any sprints higher than 500+ watts? Racing tends to bring out top performances. Did you look? You missed one possibility, you are wrong. The data is there.

You like to twist people's words to fit your notions and jump to conclusions based upon lack of knowledge. Remember your assertion that Larry O could not have done 25 mph on 194 watts because you needed 94 more watts on a faster bike? So yes, you are annoying now as you were when you basically called BS on Larry's century record on 194 watts and the real irony are your claims with no power data to substantiate.

I think I missed your congratulations to him but you did manage to intimate that it wasn't so fast and also to suggest equipment changes to get him faster. LOL

BTW.....when I started out, I could not come close to 25 mph on 194 watts (if I could make that much power) but thru lots and lots of Chung field testing, my CdA dropped from 0.200 (or a touch higher) down to a very, very low number learning a ton along the way and I do not care to share lest I suffer the wrath of people like you. 100 miles in 3:55 minutes is a firm data point, it would have been very easy for you to have reviewed his data files just in the same way you could do so with Jim's data. I provided you with the link to do so. I guess it is more fun for you to just jump to false conclusions. People like me try to educate you. You continually show a lack of knowledge, which is fine but when people give real data and real facts, to suggest something unnatural is occurring is shall we say, "yucky" ....you are pulling the same business in this thread. You do realize you derailed with the same issue over there on this same pulling adding more power. Having raced against three Cruz bikes, I believe there is an advantage in the 3-5 minute range that is akin to getting out of the saddle on an upright. I saw it. I believe it. You are real good at keyboard racing.

I am done.

http://www.bentrideronline.com/messageboard/showpost.php?p=1357627&postcount=70

http://www.bentrideronline.com/messageboard/showpost.php?p=1357828&postcount=95

 

[Osiris]

Sure, but I don't think you understand the push pull magic. One doesn't simply wiggle the bars and hold on as the bike takes off like a jet. It's a synchronization of cadence, speed, gradient , pull, sort of thing.

Of course. The principle behind it has been explained many times. The idea is that pulling the handlebars to the left while simultaneously pushing on the right pedal adds power to the pedal stroke by recruiting upper body muscles. I don't think the analysis is correct, but days of arguing over whether the theory does or does not make sense has not moved the discussion forward. A test would answer the question even without the accompanying theory, which is why I was looking forward to your experiment.

If I started with that rythmic motion on the trainer and then stopped bar movement I am "beyond" confident the cadence and heart rate would drop along with a big power drop. To keep the cadence level would mean more power which means a spike in the numbers and a yo-yo effect which is exactly the current problem.

I'm not sure I understand what you're saying here. Maybe it will come to me after one or two beers.

 

[Osiris]

I am nearly 6'4' and 225 pounds. During my competitive hockey playing days thru college and beyond, I had a top notch sprint. I would also say I rarely lost a heads up sprint within my racing class. So, I am a fast twitch guy living in a slowtwitch world although after decades, my composition has undoubtedly shifted. What I confirmed was that I had trouble making getting beyond 500 watts and into 600 watts for many, many, many months.

Then I'm completely confounded by your numbers. You have seen the video of my .6 mile sprint with the power numbers clearly displayed on screen. Nothing I've seen anywhere suggests that these numbers are high for someone my size, but you persist in thinking otherwise. I don't know what else to say that I haven't already said, and I have no interest in tilling the same soil over and over again. The rest of your post is just more self serving drivel which answers none of the points I raised.

I am done.

Fantastic. There should be nothing preventing you from keeping your promise not to post in any of my threads then, right?

 

[trplay]

A test would answer the question even without the accompanying theory,
I'm not sure I understand what you're saying here. Maybe it will come to me after one or two beers.

LOL, I've read your posts, dude you'll need more than a few beers. Moonshine might do the trick. Just saying. Meanwhile: Why don't you come up with an experiment. Hail, its been a couple of years of the same reguregietated keyboard talk and no real stuff. The time you 've spent posting the same things on this board could have been used instead on a part time job. Heavens, this alone would have provided you enough expendable cash to buy a whole fleet of Cruzbikes for testing.

 

[jond]

You're a bit late to the party. I'm not going to recapitulate all the postings that you seem to have missed, but another member named "trplay" tested this theory several days ago on his specially designed trainer. His conclusion was this: "As biased as I am for wanting the push-pull gadget to show a grand jump in power it just isn't happening. Maybe, just maybe a slight increase in power but its to small to differentiate between a legitimate increase or just our inconsistencies in pedal stroke."

I’m always in the kitchen at parties too. Hey you callin me a jonnie come lately. You don’t know my wife do you.

Lol it’s an interesting argument but I’m convinced.

Yes most cycling upper bodies of those committed are hardly powerful compared to their engine legs. So the addition is always small as part of the whole.

But then tell me what are my arms chest doing then if they are not adding to the forward impetus.

I have two trikes and a challenge hurricane bent.

The vendetta is the easiest to make power followed by catrike 700 then challenge then greenspeed gto. The df if included comes second. Of the bents it follows B.B. height. Just my observation with power

 

[Osiris]

I’m always in the kitchen at parties too. Hey you callin me a jonnie come lately. You don’t know my wife do you.

Lol it’s an interesting argument but I’m convinced.

Yeah? Well... I'm not.

Here's the thing. As most people already know, I own a V20, and of the three bents I have, it's the one I spend 95% of my time riding. I've explained many times why I prefer it to my M5 and M1, and even the CA2 I traded for it, so I won't go into that again. My point is that I have all the motivation in the world to want the claim about handlebar wagging and the extra power it confers to be true. I like speed, so any technique that will help me go faster would benefit me. But I'm not persuaded by bad arguments and bad evidence. I know the theory behind this claim, but I don't think it makes sense. I've tried twice to test the theory empirically, but on both occasions I couldn't make it work for all the reasons trplay gave. So until and unless I see some sort of objective evidence that wagging the handlebars adds power, I have no grounds to believe it does. Until then, the skeptical position is the only rational position I can take.

But then tell me what are my arms chest doing then if they are not adding to the forward impetus.

They're moving the handlebars. You can move your upper body in all sorts of ways without adding power to your pedal strokes as a result, so the mere fact that your arms are doing something doesn't lead to the conclusion that they're doing something useful.

The vendetta is the easiest to make power followed by catrike 700 then challenge then greenspeed gto. The df if included comes second. Of the bents it follows B.B. height. Just my observation with power

Since you've apparently mastered the art of wagging the handlebars while riding, perhaps you can perform the sort of test I had in mind. Pick a power level that you know you can sustain for a given time, using only your legs (no arm movement). Do a few runs that way to ensure that you're getting consistent power numbers. Later on when you're fully rested, repeat the same experiment while wagging the handlebars in the manner you're used to. If there are any resultant power gains, you should be able to sustain the same wattage for a significantly longer time, or produce more power for the same amount of time. Performing experiments like this is rather tedious because it takes many repetitions to ensure consistent and believable results, but I can't see another way to do it.

 

[jond]

Experiment heck I’ve got 40 000 klm plus on the vendetta. With a power meter I don’t need to experiment. I’ve already done it confirmed it and see it.

To rest my legs I swing the boom .

At a full tilt sprint we all pull push the boom.

try it at modest power and heck it’s like you are hardly pedalling. You don’t need anything except a hub based power meter. Try 180 watts bring in arms and feel it for yourself.

My arms move the boom against my feet . Forward impetus . Again I say what are my arms doing if not imparting forward impetus. It’s logical. I can trace the bottom bracket movement with my legs or arms or both. If I was more powerfully built from the waist up no doubt I would generate more power . It’s a moving mix of input dependant on requirements or desire.

Let’s agree on the bike we both like and enjoy as a marvellous opportunity to cycle fast off the shelf.

What seems logical to me may not to you .I accept you do not accept the same and that’s that.

Enjoy. I’m going for a ride to give my arms legs a comfortable workout something I can’t do effectively on my fixed boom trikes and bike without serious risk of breakage and inefficient body movement.

 

[Balor]

So until and unless I see some sort of objective evidence that wagging the handlebars adds power, I have no grounds to believe it does. Until then, the skeptical position is the only rational position I can take.

Sorry to resurrect this already well-beaten horse, but I've took some time to actually analyse my DF pedalling patterns while handlebar rocking.
It is more subtle than one thinks.

You (or, at least, I), basically, pedal by extending your leg up to point of maximum crank levelerage, than FIX your leg in a half-bent position and swing your bike INTO your leg using upper body power. You CG stays fixed, but the pedal swings into your leg, producing power without your legs muscle actually contracting.

Really doable only at fairly low cadence and, like I said, on DF you get much more levelerage (upward pedal displacement).

To get most out of it you need short boom, long tiller, wide bars and wide Q-factor.

 

[Balor]

A small tidbit about power of HPV racers:

Warren of recumbents.com, a REALLY large (if skinny) guy.

http://www.recumbents.com/wisil/barracuda/cda/default.htm


The HPV Simulator shows that the bike above would go about 36 MPH under ideal conditions on a flat course at sea level with a consistent 200 watts to push it. That's a almost exactly what I average on the 1/2 mile oval tracks or smaller I race on, but I am not generating 200 watts for the entire race. With a slight downhill slope like at Battle Mountain, and at 4500 feet, the simulator shows it would take about 600 watts to go 64 MPH, which corresponds to my performances at the event fairly well but I know I did not generate 600 watts for the entire speed run

So, that kind of correlate with FTPs of about 200 norm for HPV racers, and sprint power limited to 600-ish regions.
Admittedly, he is more of a builder than a pure racing type, but 'pure racing types' are not drawn to HPVs in the first place.

 

[Osiris]

Sorry to resurrect this already well-beaten horse, but I've took some time to actually analyse my DF pedalling patterns while handlebar rocking.
It is more subtle than one thinks.

You (or, at least, I), basically, pedal by extending your leg up to point of maximum crank levelerage, than FIX your leg in a half-bent position and swing your bike INTO your leg using upper body power. You CG stays fixed, but the pedal swings into your leg, producing power without your legs muscle actually contracting.

I accept that this may be the way you pedal a bicycle, but I've never heard of anyone else doing what you describe. The "best" pedaling technique, we're told, is to pedal smoothly around a circle, trying to avoid lopsided surges in power output. Fixing your leg in place at some point in the pedal stroke is the opposite of that.

To get most out of it you need short boom, long tiller, wide bars and wide Q-factor.

I did another series of experiments yesterday, trying to pedal uphill while wagging the handlebars. One problem became immediately clear, that I've mentioned before. Assuming that the handlebar wagging technique works as advertised, it should be obvious that it's effects diminish the less you move the handlebars. But this is just where the problem arises. It takes only a tiny bit of handlebar movement to cause a significant change in your direction of travel, so when I tried wagging the handlebars at my normal speed of travel, I nearly ran off the road. When I reduced the amount of handlebar movement to a minimum, I was still zig-zagging back and forth, which is a dangerous situation and makes it difficult to perform the technique consistently and correctly. To perform this technique safely you would either have to travel at a very slow pace, or limit the handlebar movement to such a degree that it becomes useless. This is why I was hoping trplay's experiment on the trainer would produce more substantive results, because on a trainer you can move the handlebars pretty far without the risk of crashing or running off the road.

 

[Balor]

Fixing your leg in place at some point in the pedal stroke is the opposite of that.

Well, "if it seems stupid, but it works - it is not stupid". This way you CAN add upper body power into leg power, and I hope you see it now.
As for how effective it is on a bent like Vendetta - I don't know, I don't have one and my current bents were not designed for that in mind.

This is why I was hoping trplay's experiment on the trainer would produce more substantive results, because on a trainer you can move the handlebars pretty far without the risk of crashing or running off the road.

The best way to do it would be do it while sitting up, and leaning your bike AND body in tandem to counteract positive slip angle with negative camber thrust while maintaining balance with your body. That's how I do it on my MBB (while climbing) and it *seems* effective, but I don't claim any definite advantage and my boom and front portion are kind of flexy for that (mild steel, small diameter tubing).

 

[Osiris]

Well, "if it seems stupid, but it works - it is not stupid". This way you CAN add upper body power into leg power, and I hope you see it now.
As for how effective it is on a bent like Vendetta - I don't know, I don't have one and my current bents were not designed for that in mind.

If you hold your leg still at some point in the pedal stroke, it is perfectly possible to produce power (albeit a tiny amount) just by pulling on the handlebars. This was adequately demonstrated by the weighted strings experiment in one of Jim's videos. But if you recall, the criticisms were that this "static" test does not accurately model what happens in a "dymamic" situation in which you do not fix your leg at any point, but pedal continuously. If you look closely at the video of Maria climbing while wagging the handlebars, you'll see that her pedal stroke is seamless throughout.

The best way to do it would be do it while sitting up, and leaning your bike AND body in tandem to counteract positive slip angle with negative camber thrust while maintaining balance with your body. That's how I do it on my MBB (while climbing) and it *seems* effective, but I don't claim any definite advantage and my boom and front portion are kind of flexy for that (mild steel, small diameter tubing).

Unfortunately sitting up isn't possible on the Vendetta, and without being able to disconnect your torso from the seat, you can't balance the bike by shifting your weight.

 

[Balor]

If you hold your leg still at some point in the pedal stroke, it is perfectly possible to produce power (albeit a tiny amount) just by pulling on the handlebars. This was adequately demonstrated by the weighted strings experiment in one of Jim's videos. But if you recall, the criticisms were that this "static" test does not accurately model what happens in a "dymamic" situation in which you do not fix your leg at any point, but pedal continuously. If you look closely at the video of Maria climbing while wagging the handlebars, you'll see that her pedal stroke is seamless throughout.

When you do it simultaneously, the effect is combination of arm and leg power (just like stated 'on the tin'), not preservation of leg power like I do myself as it seems. I, myself, do find outputting maximum power while spinning like you do.

Unfortunately sitting up isn't possible on the Vendetta, and without being able to disconnect your torso from the seat, you can't balance the bike by shifting your weight.

Quite possible if you install short cranks - I can attest that even 140mm cranks do not affect my power (in fact, I seem faster!), but you might want to change your gearing accordingly by installing smaller chainrings upfront or, better yet, larger on the back - makes transmission more efficient. My nearly 300 lbs on rather steep hils with 34 x 27 and short cranks mixed badly - I've ridden up all the inclines huffing and puffing like proverbial Little Engine, but got some knee pains. Fortunately, they went away quickly.

It also allows you to hit much higher cadences (for a bent, at least) - I have a combination of 26" 40mm front tire, 140mm cranks, 50T front ring and 12T min cog.
I've been doing 'cadence drills' of late and I've hit 72kmh while pedalling furiously on my latest long ride while doing 'hill surfing'.
https://www.strava.com/activities/1858652697
(Unfortunately Strava averages data, but I remember the number quite vividly)
Gear calculator suggests cadence of 144. Not particularly impressive by upright standards, but totally fast enough for me!

Oh, and you will need to switch bars to those with no drop. In my case it allows me to have MTB transmission which is, while less aero, is much cheaper than road dual controls.

With something like Sram wireless or X-shifter, you can have a VERY aero setup this way, though I suggest some 'bar ends' (aerodynamically shaped) for climbing.
I may go with that some day, but will see whether my nose cone project will result in as much a benefit as I presume first - than cockpit aerodynamics will simply not matter one bit.

 

[Osiris]

When you do it simultaneously, the effect is combination of arm and leg power (just like stated 'on the tin')

I've already explained why I don't think this can work. I have nothing to add to what I said before, so I'll just cut and paste a previous explanation:

Suppose you are pushing against the pedal with your right foot, applying 50 lbs of pressure. When you pull the handlebar to the left, you are in effect bringing the right pedal towards you and thereby adding more resistance that your leg muscles have to overcome in order to keep the pedal moving. Let's just say that swinging the handlebars to the left adds 10 lbs of force at the pedal. This means that to maintain the same cadence, your right leg now has to put 60 of pressure on the pedal. How is that any different than just pedaling harder without moving the handlebars?

Think about it this way. Suppose you're climbing a very steep grade and that you are already pushing as hard on the pedals as you can just to keep the bike moving. Let's say you're applying 100 lbs of pressure to each pedal using only your leg muscles. You can't push on the pedals any harder than that, so now you try swinging the handlebars to add more power. What happens? Swinging the handlebars pulls the pedals toward you, adding say 10 lbs of additional force at the pedal. That means your legs will now have to generate 110 lbs to keep the pedals turning. But if they can't produce more than 100 lbs of pedal pressure, then obviously they can't produce 110 lbs of pedal pressure. So swinging the handlebars doesn't get the desired result.

Quite possible if you install short cranks - I can attest that even 140mm cranks do not affect my power (in fact, I seem faster!), but you might want to change your gearing accordingly by installing smaller chainrings upfront or, better yet, larger on the back - makes transmission more efficient. My nearly 300 lbs on rather steep hils with 34 x 27 and short cranks mixed badly - I've ridden up all the inclines huffing and puffing like proverbial Little Engine, but got some knee pains. Fortunately, they went away quickly.

But crank length has nothing to do with my inability to sit up on the Vendetta. What prevents me from raising my torso any significant distance off the seat is the handlebars hitting me in the chest.

 

[Balor]

Think about it this way. Suppose you're climbing a very steep grade and that you are already pushing as hard on the pedals as you can just to keep the bike moving. Let's say you're applying 100 lbs of pressure to each pedal using only your leg muscles. You can't push on the pedals any harder than that, so now you try swinging the handlebars to add more power. What happens? Swinging the handlebars pulls the pedals toward you, adding say 10 lbs of additional force at the pedal. That means your legs will now have to generate 110 lbs to keep the pedals turning. But if they can't produce more than 100 lbs of pedal pressure, then obviously they can't produce 110 lbs of pedal pressure. So swinging the handlebars doesn't get the desired result.

And I'll repeat that work is not simply pressure (force), (you can stand on pedals all day producing pressure, but will do no actual work) but force times displacement. What we are doing here is not adding more force (though we can do that as well by pulling ON the bars, just not swinging the bike), but manipulating the *displacement*.
If you think agree that swinging the pedal into your leg adds arm power into leg power if you fix the leg, why don't you see that effect is cumulative for swinging the bike AND extending the leg?

But crank length has nothing to do with my inability to sit up on the Vendetta. What prevents me from raising my torso any significant distance off the seat is the handlebars hitting me in the chest.

It was already addressed multiple times here - you need bars with drop for your legs to clear your bars at maximum bend angle AND have your legs extended enough for good handling and aero.
For each 1cm of cranks shortening, you move the boom 1cm outwards to maintain seat to pedals distance AND your legs get less bent, gaining you 1cm on 'backswing'.

Hence, if you shortern 170mm cranks to 140, you gain 6cm leg-bar clearance, will be able to switch to bars with no drop and push the boom those 6cm in. I'm not exactly sure how comfortable to sit up Vendetta would still be (my bent is not THAT reclined and my bb is MUCH lower), but that should help a lot.
Plus, short cranks result in much more aerodynamic profile, because your feet don't go too far up and down in relatively clean air above and below your torso. I'm not exactly sure about their other supposed benefits, but less shearing load on the knees seems legit. Still, this is a matter of biomechanical fit and what works for one may not work for an other.
Just make sure you stick with it for a few hundred miles.
I hated them at first, but any drastic alteration in your pedalling dynamics cost you power. In my case it was pretty transient and it allow me to have a much better 'spin'.

EDIT:
Clarified some confusion.

 

[Osiris]

And I'll repeat that work is not simply pressure (force), (you can stand on pedals all day producing pressure, but will do no actual work) but force times displacement. What we are doing here is not adding more force (though we can do that as well by pulling ON the bars, just not swinging the bike), but manipulating the *displacement*.

You're using technical distinctions which I'm not using. The terms "force" and "pressure" in my post mean the same thing.

If you think agree that swinging the pedal into your leg adds arm power into leg power if you fix the leg, why don't you see that effect is cumulative for swinging the bike AND extending the leg?

Because of something I came to understand about physiology when I was weight lifting. It's a well known fact to sports scientists that a muscle can resist more weight than it can move. For example, your bicep muscle may not have the strength to curl more than a 50 lb weight, but it can support more than a 50 lb weight. The force a muscle can generate in a static contraction is always greater than the force it can generate in a dynamic contraction. So what that means is that while your leg may be able to resist more than say, 200 lbs, it can not apply more than 200 lbs in order to turn the pedal.

It was already addressed multiple times here - you need bars with drop for your legs to clear your bars at maximum bend angle AND have your legs extended enough for good handling and aero.
For each 1cm of cranks shortening, you move the boom 1cm outwards to maintain seat to pedals distance AND your legs get less bent, gaining you 1cm on 'backswing'.

Hence, if you shortern 170mm cranks to 140, you gain 6cm leg-bar clearance, will be able to switch to bars with no drop and push the boom those 6cm in. I'm not exactly sure how comfortable to sit up Vendetta would still be (my bent is not THAT reclined and my bb is MUCH lower), but that should help a lot.

I haven't been able to find even 150 mm cranks, let alone 140 mm. Where are you finding cranks that short?

 

[Balor]

The force a muscle can generate in a static contraction is always greater than the force it can generate in a dynamic contraction. So what that means is that while your leg may be able to resist more than say, 200 lbs, it can not apply more than 200 lbs in order to turn the pedal.

But yet again, you don't move the leg as much to make a *full turn* of the pedals if you swinging the bike into your leg as well. Hence, the workload *IS* shared.
Anyway, I don't grasp all the implications myself, but you must admit that you can, at least, *spread* the load over your legs and arms by doing either bike rocking or boom swinging (but to a smaller extent in the latter). And it can also be pretty big in effect and be a distinct advantage! (I really need to model how much this effect differs between an MBB bent like Vendetta and DF though sometime... should not be too hard in CAD)

I haven't been able to find even 150 mm cranks, let alone 140 mm. Where are you finding cranks that short?

You can either have them shortened for a modest fee at any decent bike shop, or buy some BMX race cranks, they go as short as about 120 and very cheap to boot (ebay). Most of them are square taper and not hollow-forged though (forget carbon), but what you lose in weight (as - gain ... and not much due to shortening) you gain in aero tenfold if you ask me... does your Vendetta still need external cups for fixing the chainstays though?
Some of them do use external cups - much pricier though. I've bought a set of 140mm BMX race myself AND had 170mm MTB cranks shortened by about 22mm as well.