Road bike vs. recumbent comparison

[trplay]

(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.

Well, if you guys can't see that bike leaning you are blind. Look at the last section where I increase the power to climb. It actually takes a little bit of practice to ride the thing

 

[ed72]

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:

Where you claimed 25 mph on 180 watts and 50km/h on 247 watts?

I laughed at that by inspection.

 

[Balor]

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.

That's because I've tried that, actually, on a non-leaning trainer and it got VERY weird.
Fortunately, Neo is capable of leaning (test-rode it once, loved it but WAY out of my budget) hence is a perfect platform for such a test.

 

[Osiris]

Where you claimed 25 mph on 180 watts and 50km/h on 247 watts?

My communications with Kent were via e-mail; they didn't take place on any forum. Secondly, I don't measure speed in km/h, nor measure my power output at 31 mph, so I don't know where that came from. Have a look at some of Larry Oslund's videos if you want to know how efficient my M5 is. Larry's numbers compare very well to mine:

 

[Balor]

How on earth does it prove that moving the handlebars while pedaling produces more force than your legs alone are capable of producing?

You are equating force with WORK. You should not. And that's exactly kind of details where devil might be hiding.
Admittedly, I'm not mechanically inclined enough to fully grasp underlying mechanics, but I don't think it can be dismissed out of hand.

 

[ed72]

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."

I already did. You don't understand. It is more about the distribution of forces over time (over the stroke) and also over more muscle groups.

Let me try this. First, stop thinking of your bike like a nitro fueled drag car or 200 meter sprints. Think more in terms of FTP or under and the production of lactate and H+ ions that inhibit power output locally.

When performing work aerobically, spreading the forces out and operating amongst many muscle groups with each at optimal torque or force is more efficient and yields a higher aerobic output than concentrating the work on fewer muscle groups. You don't believe me. Fine. Explain why rowers have the highest VO2 max amongst all athletes....

It is obvious to me as Jim's simple torque demonstration.

You didn't believe Jim's on the bike power measurements nor did you believe the increase in torque measurement. What muscles creates the momentary torque.....I already wrote that in other post. What would be interesting is where in the pedal stroke is this torque applied on a V20 by an experience Cruz rider. I don't know but would be willing to bet that it is at top dead center or just after. I spent a few hours watching Larry pedal and from my experience, getting over the top of the stroke on a bent is harder and I think that is what my eye saw. Would you believe my peak power increased from 737 to 929 watts just with my new crank? Of course not. I could explain why til blue in the face and you would just argue. When I get to 1250+ watts, I'll take it back....but might need QXL rings on top of that to get there.

Your position that you make as much peak power as someone else standing as you sitting is a bit silly. Ever see a Tour de France field sprint with a single rider seated while sprinting??????????? Never. They get out of the saddle and while pushing down with one foot, their glutes, back, and lets just say arms engage in the opposite, rotary path. I love the slow motion videos showing the handlebars bending. What bends those bars? Wait, its the legs. Track is a different beast.

As far as your mechanical engineer racer friend, hearsay appeal to authority much?

How would you explain why cruz bikes climb short steep hills so well? I have read dozens and dozens of such accounts from riders who have many different bents. In fact, I have never heard the opposite. Take that fast bent of yours and the V20 to that pimple of a hill, Sugarloaf. You'll be faster (eventually) on the V20 especially that short 12-13% pitch towards the top. Talking about flat strava segments is useless because of changes in variables day to day or minute to minute but time up a hill usually tells the truth and takes a lot of variables out of mix. Watch your power meter and learn how to profit from the inherent advantage of the V20 or should say the same advantage as an upright.

 

[Balor]

How would you explain why cruz bikes climb short steep hills so well?

I should note that I've gained a massive benefit in hill climbing on my MBB bent (as heavy and even less aerodynamic than my first, RWD bent) without any boom swinging, because, just like Osiris said, I was way too wary to do any movements not related to steering on MBB.
I did pull on the bars a lot, but I certainly don't remember any boom swinging, plus my bars were *really* noodly (though it might actually help in a way not unlike Heine's planing but I'm far from sure).
That's is why, while I *do* find it plausible for exactly reasons you mention, I don't find it much likely that it was boom-swinging that made MBB so well-climbing for me - just icing on the cake, so to speak.
It cannot be transmission efficiency either - gain in speed was on order of 20%, not 5% as per Marco Ruga experiments.

Track is a different beast.

Would track sprinters lower their cadence and rock their bikes if they could shift their gears?
I'm not very interesting in cycling as sport per se, but I've heard that cycling teams sometimes feature a dedicated sprinter that is basically 'carried' all the way to the finish line and then 'unleashed' (to compete against a similar sprinter from an enemy team ).
Anyone heard such teams employing world-class track sprinters and does their technique differ?

 

[ed72]

My communications with Kent were via e-mail; they didn't take place on any forum. Secondly, I don't measure speed in km/h, nor measure my power output at 31 mph, so I don't know where that came from. Have a look at some of Larry Oslund's videos if you want to know how efficient my M5 is. Larry's numbers compare very well to mine:

I made no mention of Kent Polk e-mail.

I said I laughed at your assertion of needing 180 watts for 25 mph.......super low imputed CdA of 0.153 while 30 mph (wrote 50...sorry) imputes an off the charts, crazy 0.127 CdA. 1) Does not add up 2) these speed/power values are off the charts. 3)Larry has spent considerable time optimizing and his aero drag is higher. This leads me to believe you use Strava segments to report performance. In any case, not reliable data because of even slight wind and very slight elevation changes that do not register on your Garmin will skew the speed/power ration significantly. If you want to measure aero, Chung method or steady power on out and back course on calm day is not bad. Correcting for atmospherics (temp, RH, pressure) and total weight is essential. Some days are fast, some are slow.

Aren't these your numbers...
Riding solo at 30 mph: 247-250 watts
Riding solo at 27 mph: 210 watts
Riding solo at 25 mph: 180 watts
Riding solo at 23 mph: 140-150 watts

The lowest CdA for an upright that I have read was like 0.181 but 0.21-0.22 is top shelf. Larry is probably slipperyer than I but I am still figuring it out. He needed 194 watts for 25.4 mph on a track, which would put his CdA up around 0.171 although I had to make a few assumptions on RHO knowing it was a bad day for speed.....cool and not much moisture in the air (dry) and Crr being on the track should be 0.0035 compared to most decent roads that are closer to 0.005. You do realize 247 watts for 30 mph is actually a touch better CdA than Aurélien Bonneteau's CdA for the hour record? 194 watts for 25.4 mph is pretty slick but doable, isn't it? Maybe 0.165 ish.....did not figure it out. Ballpark

Let me put it a different way, if your FTP is 276 watts or thereabouts (I forget.....you wrote it), you should have no problem doing a 3:20 century with those aerodynamics. 3:30 would be a piece of cake. Just work on endurance a little. WRT Larry's videos....I think I watched them all...

CdA measurements are fickle. Maybe you calculated wrong. I was doing Chung tests today. The results were not conclusive due to 3-4 mph wind across, this is barely detectable air flow. I was testing my 2-Spoke vs. the Flo Carbon 60. 2-Spoke was better but the magnitude....needs more trials. I've tested and tested lots of stuff but the results are not so conclusive for small gains. It takes lots of runs and then real world testing because air is never clean and wind tunnel data or Chung data is just the start as far as I am concerned.

Yes, I think you pulled those numbers out of the nether.

 

[ed72]

There is always a sprinter on the team. They ride the wheels of team members known as the rouleurs, big guys who can lay down big power and speed for 4-6 minutes. 20km from the finish, one after another the team riders and maybe the Lieutenent will protect the sprinter carrying him close. Then, it is mayhem. Here are some Peter Sagan sprint finishes. If you saw closeups in slow motion, the bars, stem, fork, and front wheels would be distorting under the power.

I just find it absurb to think the upper body does not provide power say going up a steep short climb on a V20. Maybe someday my freaking pain will go away and my gimpy arm will let me try one. I could be wrong.

 

[Balor]

Larry has spent considerable time optimizing and his aero drag is higher.

I recall his hour effort was on 300 watts for 50 kmh average (on his lowracer, of course)

By the way, Ed, have you seen any 'streetliners' on PBP?
Like those of Tetz foamshells or Rotator Coyte?

I mean, Steve (Speedy) claims to do sub 2 hour metric century on 200 watts (quite believable if you look at racing speeds of similar bents).

 

[Osiris]

I already did. You don't understand. It is more about the distribution of forces over time (over the stroke) and also over more muscle groups.

Let me try this. First, stop thinking of your bike like a nitro fueled drag car or 200 meter sprints. Think more in terms of FTP or under and the production of lactate and H+ ions that inhibit power output locally.

When performing work aerobically, spreading the forces out and operating amongst many muscle groups with each at optimal torque or force is more efficient and yields a higher aerobic output than concentrating the work on fewer muscle groups. You don't believe me. Fine. Explain why rowers have the highest VO2 max amongst all athletes....

It's perfectly obvious to anyone that spreading out the load across more muscle groups allows you to do more work. I used the example of twin cranksets to illustrate that point, remember? I'm not going to spend time to once again respond to claims that I never made. It is utterly pointless to devote more and more time to arguing over which conceptual model you or I or Balor think best represents what's taking place when wagging the handlebars while pedaling. We now have a fellow who has built exactly the setup I proposed over a year ago. You don't seem to have any objections to it, so I suggest we wait and see what his results are. I have no reason to suspect bias will skew his results, but that's something I cannot say about Jim's results. Even Jim concedes that.

What would be interesting is where in the pedal stroke is this torque applied on a V20 by an experience Cruz rider.

Yes, that's exactly what I said in one of my responses to Balor. While my own test showed no difference when wagging the bars, the fact is that this movement has to be carefully timed to coincide with the pedal strokes to work. I haven't yet acquired the experience to be sure I was performing the movements correctly, so I don't count my negative experience as a refutation to Jim's (and other's) claim. As I've said before, I don't have any predetermined beliefs as to whether or not it will work. My arguments have been directed against the alleged "proofs" for it, which I think are terribly flawed.

Would you believe my peak power increased from 737 to 929 watts just with my new crank? Of course not.

Correct. Nor would I expect you to simply accept my word when I make an extravagant claim. I adhere to the principle that extraordinary claims require extraordinary evidence, and an unsupported claim is no evidence at all.

Your position that you make as much peak power as someone else standing as you sitting is a bit silly.

My goodness, you do have an amazing talent for misunderstanding. I never once said that I make as much power sitting as someone else does standing. What I said was that I made more power in a seated position than I could standing, whereas the other fellow made the more power standing than he could in a seated position.

Track is a different beast.

Oh? And why is that exactly? Why is it that Olympic sprinters perform best seated?

As far as your mechanical engineer racer friend, hearsay appeal to authority much?

I wasn't making an argument. I was merely reflecting on the fact almost no one thought that Jim's weighted string demonstration proved what he thought it did.

How would you explain why cruz bikes climb short steep hills so well?

I don't feel the need to explain something that I've never witnessed. I'm one of only two Cruzbike owners in my area now, so I've never seen any evidence that Cruzbikes climb short steep hills better than other bents. That certainly hasn't been my experience on the V20, but as I said earlier, I don't have the requisite technique yet to test it. There was another V20 rider named Blake who occasionally came on our group rides. It was his bike that got me interested in the V20, but I always climbed hills faster than he did on both my CA2 and M5, neither of which are known for being particularly good climbers. That comparison proves nothing however, because it could simply be due to different levels of fitness. Unfortunately Blake's V20 was destroyed in a car accident, and he now rides a trike. The only other Cruzbike rider I'm aware of is Ben Tomblin, but he lives far away so it's not likely we'll ever ride together. He's a seasoned racer, so I might just drop him a line and see where he stands on the subject of handlebar wagging.

I have read dozens and dozens of such accounts from riders who have many different bents. In fact, I have never heard the opposite.

Then you definitely need to talk to Kent Polk. He doesn't think much at all of Cruzbikes. According to him, Cruzbike's claim to having built a superior hill climber is easily refuted by what he's seen in races. I don't have his e-mail on the subject any longer, but I got the distinct impression that he thought the claim was a case of deliberate fraud.

Take that fast bent of yours and the V20 to that pimple of a hill, Sugarloaf. You'll be faster (eventually) on the V20 especially that short 12-13% pitch towards the top.

There is a much steeper hill that I stumbled across by accident. It's not nearly as long as Sugarloaf and definitely not as well known, but I think Strava lists its average slope as 17%. It was so steep that my front wheel actually lost traction, but I somehow managed to muscle my way to the top in the big gear. Next time I'll try to remember that the V20 also has a smaller ring! It would be the ideal hill to test the bar wagging theory on, assuming I could pedal smoothly enough to maintain traction.

 

[RojoRacing]

Then you definitely need to talk to Kent Polk. He doesn't think much at all of Cruzbikes. According to him, Cruzbike's claim to having built a superior hill climber is easily refuted by what he's seen in races. I don't have his e-mail on the subject any longer, but I got the distinct impression that he thought the claim was a case of deliberate fraud.

Totally, how could someone ever claim a bent could climb better then any other bent in extreme mountain races when there only ever one bent in those extreme mountain races. I mean beating a bunch of elite DF racers in such races proves nothing related to their claim the Cruzbike climbs better then other types of bents :lol

 

[ak-tux]

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.

....

There is a nice comparative article with power mesaurments by Marco Ruga where he compares a DF, his carbon MBB (aka ReV), A cruzbike Silvio MBB, a Bachetta Aero(RWD), and a Traix Phantom RWD recumbent performance.
It's quite interesting to read. (You may need google translate):

https://biciclettereclinate.blogspot.com/2018/03/test-comparativo-fra-reclinate-parte-1.html

An older article(no power measurements):
https://biciclettereclinate.blogspot.com/2017/10/geometria-ideale-per-la-salita.html

 

[Balor]

Totally, how could someone ever claim a bent could climb better then any other bent in extreme mountain races when there only ever one bent in those extreme mountain races. I mean beating a bunch of elite DF racers in such races proves nothing related to their claim the Cruzbike climbs better then other types of bents :lol

If you put 250 lbs, ~20% BF of *me* on Vendetta and I start claiming local KOMs like this:
https://www.strava.com/segments/4471749

It would totally prove something (likely, existence of magic )

Yet there is no magic out here, unfortunately, and while I am indeed much faster uphill on an MBB bent than MYSELF on RWD bent (when it comes to 'burst climbing' at the very least) and of course would be even faster on a Vendetta, your comment, while intended to be 'tongue in cheek' I presume, is absolutely, totally true in all respects, because 'everything is not being equal' and *you* didn't ride a stiff, light RWD bent like M5 CHR (or, say, a Carbent) over same mountains. Neither did I, for that matter, but I'm 100% sure that I'll never be as fast uphill on a bent with high BB, even if it is made by indestructible and lighter than air Unobtanium. It just does not work for me - about 4 inches seems an absolute limit before I start getting numb feet and it progressively gets worse from there, and power drop during climbing likely start way before that.

Technically, a bent that allows for DF-like power delivery (Marco Ruga's bents comes to mind indeed) AND efficiency AND weight would indeed be faster even during pure uphills on all but the absolutely steepest (10+%) inclines, but even you admit that being in a one fixed position makes sustained climbs harder at the very least due to inability to 'spread the load' by varying positions.

 

[Osiris]

Totally, how could someone ever claim a bent could climb better then any other bent in extreme mountain races when there only ever one bent in those extreme mountain races. I mean beating a bunch of elite DF racers in such races proves nothing related to their claim the Cruzbike climbs better then other types of bents :lol

That's exactly right. But I can practically guarantee that someone else reading what you've written above would come to precisely the opposite conclusion.

 

[Osiris]

There is a nice comparative article with power mesaurments by Marco Ruga where he compares a DF, his carbon MBB (aka ReV), A cruzbike Silvio MBB, a Bachetta Aero(RWD), and a Traix Phantom RWD recumbent performance.
It's quite interesting to read. (You may need google translate):

https://biciclettereclinate.blogspot.com/2018/03/test-comparativo-fra-reclinate-parte-1.html

An older article(no power measurements):
https://biciclettereclinate.blogspot.com/2017/10/geometria-ideale-per-la-salita.html

VERY interesting articles. Thanks for posting them.

 

[trplay]

Well , well a great litle trolling post by non-Cruzbike riding folks on a Cruzbike forum rehashing a stale debate using already posted ancient links. You gotta ask. Do you have anything new? Wait, I have one! Does anyone know the Cruzbike success record for the elite climbing Hoo-Doo race compared to other recumbents? I wonder why there is such a discrepancy ? Maybe it's not only do we Cruzbikers look cooler on our bikes but the Cruzbike genetic climbing pool is superior. Would love to see some of those Cruzbike skeptics with the fancy stats give the Hoo-Doo a go.

 

[Balor]

Maybe it's not only do we Cruzbikers look cooler on our bikes but the Cruzbike genetic climbing pool is superior.

In a way, it might be a selection bias indeed. It is not like Rojoracing was known to be a poor, slow climber (and descender ) way before his recumbent foray.
I find MBB bents work great for me as far as comfort and power delivery is concerned, but my climbing exploits will not impress anyone even if you give me a Vendetta and pump it's tubes full of helium or something .

The fact that Rojo can generate VERY close power number on DF and on a Bent is much more interesting.

By the way, Osiris, how do YOU compared you power numbers between Vendetta and your DF/other bents, climbing and level ground?

 

[Osiris]

By the way, Osiris, how do YOU compared you power numbers between Vendetta and your DF/other bents, climbing and level ground?

Power numbers between my 3 bents seems to be about the same. On the DF, I can produce much more power, especially at the top end, where it's in the neighborhood of 200 watts more. My experiments last week suggest that the higher cadence I can achieve on DF's accounts for most of that difference, though.

 

[LMT]

Give it a rest please Balor.