Road bike vs. recumbent comparison
- Thread starter Osiris
- Start date
- Status
Balor
Zen MBB Master
Why exactly rocking a road bike is different from boom swinging? In both cases your handlebars are NOT connected to your cranks and you only manipulate your distance to pedals via them.
Yet DF races do it. *I* do it on DF, and I think it gives me more power. I do it *instinctively*, too. Have you ever done it yourself?
Just to be clear, my recent power and data posts pertained to Rotor RS4x crankset, which uses round rings. The elliptical rotor is generated by a two axis rotation in the crankset itself, complex, heavy, and ugly but I am 100% convinced it makes more power. Off the top of my head, I measured 7.8% more power on 5 minutes and 5% more FTP. This increase is a bit less than a University in Spain measured and also the professor from Italy (I posted the links to those studies) but those data were from ride 1 and ride 2. I suspect I make even more power now based upon chopping 3 minutes off prior PB climb (13 minutes down to 10). I also posted a link showing the anticipated benefit by degree of ovality, which also depends upon cadence. It is no surprise to me that nearly round Q rings would show no power benefit (it would be very small and hard to measure)
I can't ride a MBB due to health issues but what made me a believer in the extra power conferred by the design was racing with Larry O., Jim, and Will P. Coming out of the corners, the three of them had a significant power advantage on me. Could be me or it could be the platform. I just know I never had trouble holding wheels coming out of corners in Crits on a road bike. Larry had the most upper body interaction; it looked like he was wrastling an alligator. Jim was smooth and razor straight. I could see significant upper body engagement when Will came out of the corners (and left me in the dust). I also know what Jim and Larry's numbers are (they post a lot of data) and surely I could be wrong as I have many times in life, but I think the proper upper body interaction on the cruz bikes over hard anaerobic efforts gives an improvement in power over what I ride. Steady state efforts? No benefit in my estimation. but, where are races won? 5-8 minute efforts are key.
I can't ride a MBB due to health issues but what made me a believer in the extra power conferred by the design was racing with Larry O., Jim, and Will P. Coming out of the corners, the three of them had a significant power advantage on me. Could be me or it could be the platform. I just know I never had trouble holding wheels coming out of corners in Crits on a road bike. Larry had the most upper body interaction; it looked like he was wrastling an alligator. Jim was smooth and razor straight. I could see significant upper body engagement when Will came out of the corners (and left me in the dust). I also know what Jim and Larry's numbers are (they post a lot of data) and surely I could be wrong as I have many times in life, but I think the proper upper body interaction on the cruz bikes over hard anaerobic efforts gives an improvement in power over what I ride. Steady state efforts? No benefit in my estimation. but, where are races won? 5-8 minute efforts are key.
Last edited:
Osiris
Zen MBB Master
Of course I have. Years ago I was "competing" with an aspiring racer in one of my training classes to see which one of us could produce the greatest max power. I produced the most power when seated, pedaling at a high cadence, whereas he produced the most power when standing on the pedals and pedaling at a slower cadence. We couldn't figure out why one technique worked better for him and another worked better for me, but there was no arguing with the results. Speaking of results, his max power was produced while on a stationary trainer, which prevented any side to side rocking motion, so the idea that he got those high numbers by rocking the bike is obviously not the case.
When you pedal standing up and put as much power as you can into your pedal strokes, it's virtually impossible to keep the bike from rocking from side to side. You and Ed seem to think that the rocking motion itself is what's responsible for the added power, whereas I would say that it's just an unavoidable consequence of placing hugely uneven amounts of pressure on one side of the bike and then on the other. Obviously the reason this doesn't happen when pushing as hard on a recumbent or when seated on a DF, is because the rest of your body is connected to the bike/bent in such a way as to prevent it. You yourself observed that Olympic sprinters don't rock the bike at all, and yet their sport is all about generating the most power out of every pedal stroke. If rocking the bike from side to side resulted in higher power outputs, there is little doubt that Olympic sprinters would have found a way to put that to use.
ak-tux
Zen MBB Master
I think rocking a DF from side to side during hard efforts allows one to enlist different muscle groups while, in alternating manner, resting others. It also allows the rider to brace themselves against the handlebars and pull while pushing the pedals, especially when off the saddle.
In essence, the swinging boom on an MBB recumbent allows a similar action but on a more horizontal plane. The swinging of the boom may be less extreme and less obvious ( than on a DF ) but it's definitely there. (If you place a camera on the handlebars and record your shoulder motion when climbing you will see it.) One needs to brace against the handlebars when generating high torque on the pedals on an MBB bicycle. For lower torque values, one can ride hands free and stabilse with the torso agaiints the seat.
Take a look at my shoulders in my video at about 5:17
In essence, the swinging boom on an MBB recumbent allows a similar action but on a more horizontal plane. The swinging of the boom may be less extreme and less obvious ( than on a DF ) but it's definitely there. (If you place a camera on the handlebars and record your shoulder motion when climbing you will see it.) One needs to brace against the handlebars when generating high torque on the pedals on an MBB bicycle. For lower torque values, one can ride hands free and stabilse with the torso agaiints the seat.
Take a look at my shoulders in my video at about 5:17
Osiris
Zen MBB Master
Not that I'm aware of, but an easy way to test the efficacy of sideways rocking as a factor in power production would be to compare a given racer's max power obtained on a trainer with the max power numbers obtained on the road. If he's standing on the pedals in both cases, then the answer should be clear.
Looks like the proposed fixed vs freely moving boom test has already been conducted
https://cruzbike.com/forum/threads/...oom-recumbent-bicycle-power-production.11644/
https://cruzbike.com/forum/threads/...oom-recumbent-bicycle-power-production.11644/
Balor, I don't believe 90% or more of what I read WRT bent forums simply because the posters do not use power meters and if they do, they almost never employ a control let alone correct or even appreciate differences in environmental conditions and their impact. It is often said power decreases with a lower angle on the seat. 100% not true in my case and I have the power data to prove it. Most poster just say stuff like....I breath harder with the lower seat and I was huffing and puffing up the road to my house or my average speed on my 20 mile loop was 1 minute less. Useless.
Check out this blog post, I wholeheartedly agree with what the author wrote. I think there was a 50 page mess over there on this topic and the only two riders who knew half a damn no longer post there. I gave a link to Steve Hogg who in my opinion is one of the top fitters worldwide. I spent my first 9 months of benthood focused on the damned legs with very little effect. 3-4 months on breathing has been an absolute eye opener. There is research out there on lung function by different body positions. I have a couple secrets that got me massive aerobic power improvements jsut from how I breath but since it is N = 1, I don't want to ridiculed.
http://www.fietsersafstappen.nl/english/focus-breathe-how-to-climb-fast-with-a-recumbent/
Osiris
Zen MBB Master
Which "different muscle groups" are you referring to?
Perhaps I'm misunderstanding you, but we may be talking about different things here. All your video shows is that your shoulders are moving as you pedal. That's to be expected. When you pedal a MBB, you have to pull on the handlebars to counteract pedal steer, and that pulling action causes your shoulders to move. My shoulders move in just the same way as yours when riding my Vendetta. In fact, they move even when I'm riding bents with a fixed boom.
The video in this cruz blog post proves to me at least what I believe.....the counter pulling of the upper body creates more power (torque thru various levers)
QED
https://cruzbike.com/blog/2017/03/18/upper-body-aids-propulsion-on-a-cruzbike-bicycle/
QED
https://cruzbike.com/blog/2017/03/18/upper-body-aids-propulsion-on-a-cruzbike-bicycle/
Osiris
Zen MBB Master
Interesting. And kudos to Jim for saving me the trouble of having to point this out:
"2) Only one subject was tested, and that subject (me, the author) is also an owner of Cruzbike, Inc., and therefore may have consciously or unconsciously biased the intensity of his efforts"
This underscores my point about the need for consistent and repeatable test results achieved by an unbiased test subject.
Taking a close look at the results, Jim's numbers are very odd. Jim is a bigger, younger guy than I am, and has done loads of training and racing, whereas I only ride once or twice on weekends. Why then are his numbers so much lower than mine? 492 watts for 5 seconds? That's about half what I'm capable of. It's only when we get down to the 1 minute interval that his numbers begin to look like mine, but at the 2 & 5 minute intervals (249W & 217W, respectively) there's a huge difference again. My last 8 minute interval on the trainer resulted in an average of 312 watts. After a long rest, I performed another 8 minute test and averaged slightly under 300 watts. Even my FTP of 278W is much higher than Jim's five minute interval. What gives?
I could not make more than 525 watts Peak Power for a long time on my bent and even with a lot of power work on hills and 10x1 intervals, I can't come close to your peak power numbers.
What gives? Is that a serious question?
You make a lot more power across the board. Or your power meter needs calibrated. Is there another possibility?
I know for sure his numbers reported are about right based upon racing with him and his reaction to some tests although I am pretty sure they are a little higher than when he did these tests but not in your power meter's league
What gives? Is that a serious question?
You make a lot more power across the board. Or your power meter needs calibrated. Is there another possibility?
I know for sure his numbers reported are about right based upon racing with him and his reaction to some tests although I am pretty sure they are a little higher than when he did these tests but not in your power meter's league
Balor
Zen MBB Master
I've read this article long ago in beginning of my 'adaptation' period and it, frankly, it made zero sense to me for reasons I've described above.
Again, let me show:
DF, a Chinese niner with 2.35" tires, 600mm bars and stubby aerobars I use mostly for downhills and headwinds because long-term use of those make my back hurt a lot:
My weight - about 90 kg, 12 kg bike + stuff
https://www.strava.com/activities/147943553
My weight is up to 100 kg, 20 kg RWD cromoly steel bent (plenty stiff, built like a tank, Marathon supreme 2.0 tires - should roll similarly if not better) + stuff:
https://www.strava.com/activities/275932010
I've spend winter on a trainer plus already completed one 200 km brevet before with rather pathetic results as well:
https://www.strava.com/activities/264455640
And let me restate - lack of breath was certainly NOT a problem! Yea, that's a lot of extra weight, but even given relatively hilly (by our standards) track it simply cannot account for such massive drop in average speed and I certainly tried as hard as I could.
I eventually got faster and faster, but it took a move to MBB bent to get anywhere near my MTB performance, and I'm still a bit short of my road bike performance on short distances (didn't do long distance on road bike, back problems).
Still, I'd be very interested if you share what you've found about breathing on a bent in particular, cause I, indeed, very limited by my breath on my current bent *now*. But it took nearly 4 years!
I guess attacking the 'why bents don't climb' problem from different angles is nessesary.
I'm most concerned about bracing and need for *rigid* bracing that my body does not really provide unless you go out of your way with greatly changed pedalling style, and impared blood flow to the legs with high BB. (Plus 'controability' issue and I think I already solved that one)
Osiris rises interesting points about cadence.
You about how bracing and body position also affect your ability to breathe effectively, that is pretty important for anything but 5-second power brackets (which actually suffer the most on a bent).
Marco Ruga has interesting study about transmission efficiency on MBB vs RWD.
ALL of those must be considered and put together to create a more or less comprehensive model of a bent that maximises aerodynamics, comfort, transmission efficiency and power delivery across all power brackets - and how they interact so one can maximise one or the other without significant impact on other parameters.
Osiris
Zen MBB Master
Just to be sure we're talking about the same thing, my Garmin is set for 5 second averaging, and my best result so far is 1150 watts. That's the number I'm comparing to Jim's 5 second average, which seems ridiculously low for someone like him.
I have three power meters. All are different versions the Garmin Vector. All three produce numbers that are very close on the various test segments I ride. I've watched Larry's videos and compared power numbers to see if I could beat him in a race. He uses the same Vector 2 pedals I have, and his numbers are nearly a match for mine. About a year ago, I also compared my power numbers at various speeds on the M5 to Kent Polk's results. His M5 is practically identical to mine, right down to the Railgun seat and full disk wheel in back, so I wasn't surprised to see that our results matched pretty closely. The only significant difference was at 30 mph, where I was putting out less power than he was, although he said differences in road surface could account for it. So given all that, I would say there's little or no possibility that my power data is wrong.
Take a look at this video. This was my last ride on the CA2 before I traded it for the V20. Bear in mind that I hadn't intended to go for the KOM, so I was already a bit tired by the time I reached this segment. If I'd been fresh, my numbers would definitely have been higher. Max power was 780 watts, and my average power during the 1:05 interval was just shy of 500 watts:
You are making a time to distance argument. I agree. I am working on all of these performance aspects in preparation of crushing it next August on PBP.
Here is where you and I fundamentally disagree. When someone like Tim Turner supports such an article, I take serious note rather than a dismissive tone. I have increased FTP over 25% primarily with focus on breathing, breathing exercises, and position on the bike. You and Aerolus want proper studies. Scientific studies.
Honest question. Have either of you ever funded such studies in any field or have you reviewed and approved such protocols or results? There just is not that kind of money in this industry.
Jim's hung weight and torque measurement is sufficient for me on the other matter at hand.
trplay
Zen MBB Master
Here's a video using the trainer while monitoring the cadence, heart rate, power, and incline as it happens on Zwift. As depicted in the video you can easily switch from no hands to hands, push-pull to pull-push. The Neo is suppose to be one of the most accurate smart trainers out there. This should work if you can maintain a constant rpm or wattage. Easier said than done but ball park is doable. I'll see if I can talk Connie into playing to see if the results change since the bike is fit for her.
Osiris
Zen MBB Master
They do tend to be more convincing than unsupported claims, yes.
It doesn't take money to come up with credible experimental results to test this particular claim. We're not looking for the Higgs-Bosson particle. All you need is a power meter. How much money do you think it cost Jim to perform those intervals on his trainer and on the road? Nothing. How much money did it cost the fellow to mount his trainer to a rolling platform? A few dollars? I don't think we need a loan from Bill Gates to get to the bottom of this.
Except that the hung weights experiment is completely useless. It tells us what should be obvious without even performing the test; namely, that pulling the pedal back against resistance produces a measurable force. How on earth does it prove that moving the handlebars while pedaling produces more force than your legs alone are capable of producing? I'm still waiting for someone to provide me with an explanation. When Jim first posted that silly experiment, it provoked quite a bit of laughter on other bike forums. One retired racer who also happens to be a mechanical engineer replied that, "He [Jim] doesn't understand anything about mechanics."
Osiris
Zen MBB Master
Excellent. I'm looking forward to seeing the results. When I first proposed this test, someone (Balor?) objected that unless the bike is capable of leaning from side to side, it won't accurately duplicate the mechanics involved in riding. He's right, but I can't see how it's inability to lean would invalidate the experiment.
- Status
