Road bike vs. recumbent comparison

[Osiris]

I've been looking closely at the power data from this morning's ride on the V20, and something very interesting showed up. Much of today's ride was devoted to experimenting with handlebar wagging to see if I could extract any extra power using this method. The first results were negative. These consisted of 10 hill repeats on a short but very steep segment. The first run was done without wagging the handlebars, the second run was done while wagging the handlebars, and so on until I had completed five climbs using each technique. Nothing indicated any power increase. In all the runs, my power output fluctuated between 260-290 watts, and on the whole looked pretty much identical. I have in the past expressed my doubts that this sort of test would be of any use in revealing modest power gains, so I performed another test on a much longer (.70 mile) climb. I've ridden this segment 411 times according to Strava, so I have a ton of power/speed data to compare today's result to, and this is why today's numbers are so interesting. What my Strava results show is that I was faster on that segment today than I have been at any time since November of 2014! That 3rd place finish was a statistical anomaly because I was fully rested then, whereas in every other case the climb was done near the end of a 2 hour ride, when I'm already exhausted. I certainly didn't feel fresh today, especially after all those hill repeats, so this result is all the more surprising. Today's climb was done at an average speed of 17.4 mph. The next fastest average speeds, going back to 2014, were: 16.2, 16.2, 16.1, 15.9, in that order. An improvement of over 1 mph average over my best previous results is hard to ignore. This stretch of trail is surrounded by heavy tree growth, so wind (had there been any) would not have affected the results. I don't do any sort of training, so an improvement in leg strength or aerobic capacity isn't a likely culprit. Many more tests will need to be done to see if this was a fluke or actual evidence that handlebar wagging contributes to power output, but it's the first hint I've seen suggesting that it might.

 

[Balor]

Well, spreading the load between muscles can help both explosive power AND longer term power, but I presume, unless your upper body is in comparative shape to your legs (and you must be pretty damn ripped for that to be so, much moreso than a typical cyclist) - disbalance in leg and body power (especially since arm mechanical advantage on Vendetta is pretty small) can prevent you from having meaningful results at very high power.

I'm not an exception to a 'cyclist body' (unless you count all that fat), but arms of, say, Maria Parker are pretty well-toned.

 

[Osiris]

Well, spreading the load between muscles can help both explosive power AND longer term power, but I presume, unless your upper body is in comparative shape to your legs (and you must be pretty damn ripped for that to be so, much moreso than a typical cyclist) - disbalance in leg and body power (especially since arm mechanical advantage on Vendetta is pretty small) can prevent you from having meaningful results at very high power.

I'm not an exception to a 'cyclist body' (unless you count all that fat), but arms of, say, Maria Parker are pretty well-toned.

I can't speak for all Cruzbikes, but the Vendetta's steering geometry actually requires very little force at the handlebars to counterbalance the force being applied to the pedals. My arms aren't the least bit tired from today's experimenting. I can yank the handlebars harder than I can push against the pedals, but doing that causes the bent to veer all over the trail. Keeping the front end under control when pedaling hard requires very little side to side movement, but unfortunately that also limits whatever mechanical advantage wagging the handlebars is alleged to offer.

 

[Gary123]

Now I'm a believer. When I really work the arms I consistently get 1-2mph increase on hills that I've done many many times.

 

[Balor]

I can't speak for all Cruzbikes, but the Vendetta's steering geometry actually requires very little force at the handlebars to counterbalance the force being applied to the pedals. My arms aren't the least bit tired from today's experimenting. I can yank the handlebars harder than I can push against the pedals, but doing that causes the bent to veer all over the trail. Keeping the front end under control when pedaling hard requires very little side to side movement, but unfortunately that also limits whatever mechanical advantage wagging the handlebars is alleged to offer.

That is exactly why if you are NOT getting tired when doing bar swinging, you are doing it wrong. If you cannot swing the bars far - you must substitute it with speed and power. If you are not doing it fast enough, you are getting equivalent of "spinning out", but with arms, not with legs.

 

[Osiris]

That is exactly why if you are NOT getting tired when doing bar swinging, you are doing it wrong. If you cannot swing the bars far - you must substitute it with speed and power. If you are not doing it fast enough, you are getting equivalent of "spinning out", but with arms, not with legs.

I'm swinging the handlebars at least as far as demonstrated in Jim's instructional video. More, when climbing at very slow speeds. Have you ridden a Cruzbike V20 at all? Unless you have, you don't have any idea how much handlebar movement is practical on one at any given speed and cadence.

 

[Gary123]

I've ridden the v2.1 for about 2 years. I recently went back to the original seat for more aero position and picked up about a half mph av. Not sure its worth it but I'll try it for a while to see if I can get comfortable with seat and homemade headrest.

 

[Balor]

Well, I did 200 km ride today... and here is an other test method that totally worked for me: get your legs wasted (100 kms of head wind does that), and THAN try boom swinging, for climbing and accelerations.
I can say that it absolutely, totally works - doing boom swinging makes those climbs and sprints *possible* when you otherwise simply couldn't!
Difference in peception of effort (and attained power) is simply enormous this way. I think a was still slower than fresh, and without PM data this is inconclusive, but I can say that it *totally* works at least in this case, and while the offert is not free and I've got a nasty back spasm in the process - I think it can totally win you a race sprint to finish - even if you don't get to output "more" power, but apply different (and relatively fresh) mucle groups.

 

[Osiris]

Well, I did 200 km ride today... and here is an other test method that totally worked for me: get your legs wasted (100 kms of head wind does that), and THAN try boom swinging, for climbing and accelerations.
I can say that it absolutely, totally works - doing boom swinging makes those climbs and sprints *possible* when you otherwise simply couldn't!
Difference in peception of effort (and attained power) is simply enormous this way. I think a was still slower than fresh, and without PM data this is inconclusive, but I can say that it *totally* works at least in this case, and while the offert is not free and I've got a nasty back spasm in the process - I think it can totally win you a race sprint to finish - even if you don't get to output "more" power, but apply different (and relatively fresh) mucle groups.

As you say, without PM data you don't have much to go on. Seat of the pants impressions are notoriously wrong, especially when contaminated by bias. I did exactly the test you describe yesterday by first exhausting my legs by racing up a hill until I could barely manage 250 watts. Then I tried swinging the handlebars while keeping a close eye on my power meter. The result? No change in power output.

The other problem as I've mentioned before, is that the geometry of your home built recumbent bears no resemblance to a Cruzbike, so we can't conclude that what's true of your bent is true of every other MBB. When you swing your handlebars 2 cm to the left, how much does that shorten the distance between the BB and the rider's hip joint? How far can you realistically swing your handlebars without causing serious steering problems? At what cadence does synchronizing your arm and leg movements become a practical impossibility?

 

[Balor]

Then I tried swinging the handlebars while keeping a close eye on my power meter.

Wrong!

especially when contaminated by bias

If you think you don't have a bias blind spot, you have a particularly nasty case of a bias blind spot, you know .

Anyway, this is not just 'seat of the pants'. Like I said, the difference was simply enormous, between 15 kmh crawl and 25 kmh rather lively sprint. It was NOT free - I had to breathe really hard afterwards to get out of oxygen debt, but results are extremely repeatable. You don't need a power meter for that.
Unfortunately, I'm limited by my hands and back - I get back spasms when I try pulling too much, and my hands (forearms) still hurt the day after, and back a bit. Maybe I should hit the gym...

And if yours do not, you might be doing it wrong after all - and it is not a matter of how FAR you swing the bars, but what the FORCE you apply, and at what speed. After all, if you spin the pedals a bit slower than your current gear ratio dictates, you'll get no resistance and contribute no power, you'll be just free-wheeling despite all the movement. Same applies to boom swinging, that's what I mean by 'if you fail to move the boom fast enough'. Technique DOES make or break it, this is not so simple.

And here is diagram of my bike from the CAD:

Boom straight ahead:

Bars moved one inch to the left:

How does it compare to your model?

EDIT: Corrected wrong measurement.

 

[Osiris]

If you think you don't have a bias blind spot, you have a particularly nasty case of a bias blind spot, you know .

Power meters don't have a bias. I'm running my tests using hard data because my power meter doesn't care what I believe or don't believe. If it shows that swinging the handlebars produces more power, then there will be no denying it. And should that be the case, my results as a skeptic will have much more credibility than countless uncorroborated personal testimonies, right?

Anyway, this is not just 'seat of the pants'. Like I said, the difference was simply enormous, between 15 kmh crawl and 25 kmh rather lively sprint. It was NOT free - I had to breathe really hard afterwards to get out of oxygen debt, but results are extremely repeatable. You don't need a power meter for that.

And yet when I performed the same test, it showed no increase in speed or power. If your only response is to speculate that I must have been doing it improperly, then I'm equally free to speculate that you were just pedaling harder without realizing it.

And if yours do not, you might be doing it wrong after all - and it is not a matter of how FAR you swing the bars, but what the FORCE you apply, and at what speed.

It obviously does matter how far you swing the handlebars. The whole premise of the handlebar swinging technique is that it brings the pedal toward you, so how far it brings the pedal toward you determines how much of an effect it has. If the change in distance is zero, then the result is zero power added. The amount of force certainly matters, but this force has to be proportionate to the amount of force being applied to the pedals by your leg muscles. If it isn't, your arm and leg movements won't be in sync, and the result will be a front end wobble and a loss in efficiency, to say nothing of safety.

How does it compare to your model?

I've listed all my measurements in a previous post. I would need to go back to that post to compare them with yours, but if I'm interpreting your diagram correctly, it looks like moving the handlebars 1 inch to the left only shortens the distance to your right hip joint by a mere 5 mm. Is that correct? And is that 1" a fair estimation of how far you move the handlebars when riding?

 

[Balor]

If it shows that swinging the handlebars produces more power, then there will be no denying it. And should that be the case, my results as a skeptic will have much more credibility than countless uncorroborated personal testimonies, right?

No, because you have a personal stake at being *right*. Don't deny it, everyone does it - it simply makes you a human .

Proper protocols involve some sort of blinding, and if you stare at your power meter, you might very well subconsciously limit your power output. You must *not* look at PM at all, only analyse the data afterwards, and I've already said that. Notice that you actually DID notice an effect when those conditions were met. And it is *much* easier to limit your output than push harder than you possibly can! I think we had agreed on that.

If your only response is to speculate that I must have been doing it improperly, then I'm equally free to speculate that you were just pedaling harder without realizing it.

And you might be right, *maybe* that was just a particularly strong case of placebo effect. Or it has nothing to do with boom swinging per se, but other factors like, say, change in bracing and pelvis movement or whatever. Hence, I didn't say that it was 'conclusive', but effect obviously apparent to *me*. And it is not 10-20 watts - more like a couple of hundred!

Yet I was working my upper body *really* hard, and all that power must have went *somewhere*! Just like you said, you really don't need much arm power to resist pedal torque, and my bent is not exception - this aspect of MBB bikes is severely overstated (unlike wheel flop and steering inertia aspects that hardly get mentioned).

When you do boom swinging, don't you feel a *ton* of resistance at the bars? You should, because my arm leverage is much greater than of Vendetta and I'm still working my arms off, it must be much harder on Vendetta.

I've listed all my measurements in a previous post. I would need to go back to that post to compare them with yours, but if I'm interpreting your diagram correctly, it looks like moving the handlebars 1 inch to the left only shortens the distance to your right hip joint by a mere 5 mm. Is that correct? And is that 1" a fair estimation of how far you move the handlebars when riding?

No, you didn't mention the resulting angle. Post a comparison screenshot like I did.

And I *think* I swing my bars father than that, and I *think* I 'pre-swing' them like on DF as well. You just asked for a an inch of displacement (actually, 2cm in retrospect ).
It is really hard to judge when you are working really hard though! I'll need something like a helmet-mounted camera I guess...

This stuff is not really accessible to my conscious processes - 'muscle memory', basically.

 

[Balor]

I think you can even calculate power from displacement and force, assuming that power goes into transmission (and it *must*, because the principle is quite sound mechanically - unlike, say, merely pulling on the bars on a fixed boom bike).
Point is, how can one measure force at the bars? I don't think there are any power meter grips out there .
There were some 'instrumentalised' bikes, I think at Delft, that did just that - had torque sensors at the headset.

 

[Balor]

Hmm. Let's assume I'm hauling about 300 newtons (it feels like that at least) per about 4 cm (again, seems like a realistic estimation), at ~90 RPM (remember, I have short cranks, my cadence is rather high when climbing)
It should result at about 300 * 0.04 = 12 joules per each swing, and 3 swings per each second... 36 watts.
Even assuming *all* this power goes into transmission, there is no way I can account for extra power unless other factors are involved, or I'm wildly underestimating my efforts (unlikely, my upper body is not strong).

So, you are right that I was stomping the pedals harder AS WELL, but something around 30 watts is totally realistic even for me.

 

[Osiris]

No, because you have a personal stake at being *right*. Don't deny it, everyone does it - it simply makes you a human .

The point I was making is that if the result is the opposite of what I expected it to be, then you can be certain that it wasn't the result of confirmation bias.

Proper protocols involve some sort of blinding, and if you stare at your power meter, you might very well subconsciously limit your power output.

That's certainly possible, but there's another side to it that you're not considering. If I didn't look at my power meter, I couldn't be sure that I wasn't doing something that would invalidate the results, like changing my cadence the moment I begin wagging the handlebars. Cadence has a significant impact on power production, and if I didn't ensure that it remained the same, the test would be worthless. Another thing I need to pay attention to is any changes in slope, and that too is indicated on my GPS readout. So if I were to perform these experiments without looking at my readouts, as you're suggesting, then the results will not be reliable.

You must *not* look at PM at all, only analyse the data afterwards, and I've already said that. Notice that you actually DID notice an effect when those conditions were met.

There hasn't been one test that I've performed without keeping a close eye on my data readouts.

And you might be right, *maybe* that was just a particularly strong case of placebo effect. Or it has nothing to do with boom swinging per se, but other factors like, say, change in bracing and pelvis movement or whatever.

There is a theory I've been kicking around that comes from my weight lifting days. I have no idea whether this has any role to play in the current debate, but I'll mention it anyway. When I was at my strongest and couldn't increase the weight I was able to lift in the squat, I read an article on the subject by Tom Platz, a famous body builder of the 1980's who was best known for his leg development. Platz explained that you can trick your body/mind into doing something you thought was impossible. He mentioned that when performing the squat, you should stop thinking in terms of lifting the weight up, and imagine instead that you're pushing your feet down through the floor. I thought this was nonsense at first, but it actually worked. I don't know why it worked, but I imagine it has something to do with activating certain neural pathways that weren't active previously. Could something like this be happening when you activate your upper body muscles? Maybe.

Hence, I didn't say that it was 'conclusive', but effect obviously apparent to *me*. And it is not 10-20 watts - more like a couple of hundred!

Yes, but a difference that great only gives me more reason to be suspicious. Even Jim's highly optimistic claims of a 30% power increase comes nowhere near what you're reporting.

When you do boom swinging, don't you feel a *ton* of resistance at the bars? You should, because my arm leverage is much greater than of Vendetta and I'm still working my arms off, it must be much harder on Vendetta.

I have a pretty strong upper body, so it doesn't strike me as all that much. If I had to guess, I'd say that pulling the handlebars to one side feels like 30-40 lbs. when putting out 300 watts.

No, you didn't mention the resulting angle. Post a comparison screenshot like I did.

The angle isn't what matters; the change in distance from your hip joint to the BB does. In my case, turning the handlebars 2" to the left shortened the distance by 3/4". When actually riding the bike, I can't move the handlebars that far without causing the bent to lurch from side to side. If I had to guess, I would say that 1" is more realistic. If you look at Jim's instructional video, you'll see that the amount of side to side handlebar movement isn't that great.

And I *think* I swing my bars father than that, and I *think* I 'pre-swing' them like on DF as well. You just asked for a an inch of displacement (actually, 2cm in retrospect ).
It is really hard to judge when you are working really hard though! I'll need something like a helmet-mounted camera I guess...

I've been thinking of some device I could build to measure the amount of deflection, but I haven't come up with anything so far. A helmet mounted camera might be the best thing, but I don't have one.

 

[Osiris]

Hmm. Let's assume I'm hauling about 300 newtons (it feels like that at least) per about 4 cm (again, seems like a realistic estimation), at ~90 RPM (remember, I have short cranks, my cadence is rather high when climbing)
It should result at about 300 * 0.04 = 12 joules per each swing, and 3 swings per each second... 36 watts.
Even assuming *all* this power goes into transmission, there is no way I can account for extra power unless other factors are involved, or I'm wildly underestimating my efforts (unlikely, my upper body is not strong).

So, you are right that I was stomping the pedals harder AS WELL, but something around 30 watts is totally realistic even for me.

30 watts is pretty easy to make for an adult male. In fact, it's hard for me to keep my power fluctuations within 20-30 watts just pedaling normally.

 

[Balor]

The angle isn't what matters; the change in distance from your hip joint to the BB does.

Oh, it most certainly does. I can swing the BARS much farther than you without causing too much steering deflection, and that *work* is conserved when it comes to BB to hip distance moment - I get less displacement, but much higher *force*. That is what leverage is about!

I have a pretty strong upper body, so it doesn't strike me as all that much. If I had to guess, I'd say that pulling the handlebars to one side feels like 30-40 lbs. when putting out 300 watts.

That's when you just correct for pedal torque or when you 'overswing'? 30-40 lbs is totally not much.

Let's assume 1" movement climbing at 60 RPM at force of 177 newtons... 9 watts. (Again, assuming all work going into transmission)

30 watts is pretty easy to make for an adult male. In fact, it's hard for me to keep my power fluctuations within 20-30 watts just pedaling normally.

Small wonder you failed to notice any difference!

On the other hand, I can totally feel my 40mm OD *steel* boom flex a bit when I do boom swinging, and I use not just my arms, but my entire upper body (like I said, I got a nasty back spasm and my back just only now stopped hurting from overexertion) - and I'm nott THAT much of a weakling to get that from mere ~40 lbs of force. My bent weights more than that and haul it around with without too much fuss.

You really need to work harder with your upper body. The power does not come from ether!

 

[Osiris]

Oh, it most certainly does. I can swing the BARS much farther than you without causing too much steering deflection, and that *work* is conserved when it comes to BB to hip distance moment - I get less displacement, but much higher *force*. That is what leverage is about!

I mentioned earlier that the force you generate by swinging the handlebars has to be proportionate to the amount of force you're generating with your legs. If not, you get a wobbly front end and wasted energy. In my case, a speed of ~17 mph at a cadence of ~70-80 rpm seems to produce the best results.

You really need to work harder with your upper body. The power does not come from ether!

As I said, there are practical limits to this technique. I can and have pulled much harder at slow speeds up a steep hill, but doing that at medium to high speeds causes a dangerous weave. It's especially problematic if you have to switch gears and suddenly find that your arm movements are no longer in sync with your pedaling.

 

[Balor]

Well, than perfect your technique and come back?
Unless I fundamentally misunderstand something, it should be much *easier* for you to pull much harder than I do on Vendetta, but it is vice versa, and this is not
right at all.

Just disregard boom displacement and concentrate on bar displacement, cadence and *force*. To get mere 20 watts of upper body contribution at 80 RPM you need to swing your bars with force of about 60 lbs for an inch per each pedal stroke, for instance.

 

[Balor]

Anyway, it would be really interesting to hear experiences of experienced Cruzbikers and how far/hard they do boom swinging... but I think we scared them all away .