Road bike vs. recumbent comparison

[Osiris]

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.

How did you arrive at these numbers?

 

[Osiris]

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 .

I'd be interested to know also, but it would be almost impossible to tell without some piece of equipment. I imagine it would also vary according to speed. Interestingly, Rojoracing, who is probably the most successful Cruzbike racer and climber ever, says he doesn't use the handlebar wagging technique at all.

 

[Balor]

266 newtons (60 pounds) * 0.0254 (1 inch in m) * 80 (cadence) / 60 (seconds) * 2 (swings per revolution) = ~18 watts

A bit more, like 70 pounds actually, right.

 

[Balor]

I'd be interested to know also, but it would be almost impossible to tell without some piece of equipment. I imagine it would also vary according to speed. Interestingly, Rojoracing, who is probably the most successful Cruzbike racer and climber ever, says he doesn't use the handlebar wagging technique at all.

Maybe he should? And besides, not all DF racers do it - not all of them are at Lance level. And besides, your legs can eat up all your respiratory capacity - unless they are totally shot.

So, what matters here is anaerobic capacity of your upper body.

 

[Balor]

I think a gold cross country skiing medalist (or, say, a rower) may make for a excellent 'boom swinger' test subject .

 

[Osiris]

Maybe he should?

I'm sure he would if he determined that it does anything useful. I wouldn't presume to speak on his behalf, but it occurred to me early on that he has more than anyone to gain from this technique IF it worked. I'll leave you to draw the conclusion from the fact that he doesn't.

 

[Balor]

I'm sure he would if he determined that it does anything useful. I wouldn't presume to speak on his behalf, but it occurred to me early on that he has more than anyone to gain from this technique IF it worked. I'll leave you to draw the conclusion from the fact that he doesn't.

Yea, I draw conclusion that you appeal to authority

 

[Balor]

Anyway, I was NOT doing any bar swinging for 3 years of MBB experience. Admittedly, my bars were damn noodly, and it might certainly contribute. It is a skill, and not exactly intuitive one at that. Now that I've tried, 'I am a believer' - and not just because it *seems* to work, but because there is a solid theoretical basis for it. I intend to perfect this skill to the best of my ability.
I've also witnessed how much explosive power some people get from bar-swinging on DFs firsthand (enduro racer with 800mm bars easily outsprinting road racers that must be at the very least as strong as he is... and he rocked the bike like a crazy man). Still, I am doing very rarely even on DF. Why? Likely due to balance of upper and lower body power.

 

[trplay]

Anyway, it would be really interesting to hear experiences of experienced Cruzbikers ... but I think we scared them all away .

Its called over fishing the pond. The video below pretty much sums up this thread.

 

[DavidCH]

Perhaps someone following this thread can tell me the secret to spin at 150 rpm ... I just keep on bouncing out of the saddle.

 

[Balor]

Cadence drills, short cranks and, most importantly, carefully choosing one's parents.
(Ok, maybe not the latter unless you want to match the guys on video. Former two will suffice for 150 to be sure).

 

[ed72]

This is really a third order effect going on here.

j = da/dt

 

[trplay]

Jerk physics

 

[cranky cyclist]

I just don't know what the point of this thread is! I ride a cruzbike and I go up hills almost as fast as with a DF.

 

[DavidCH]

I wonder when the thread gets frozen..? Perhaps this is the last message.

 

[ed72]

I wonder when the thread gets frozen..? Perhaps this is the last message.

Is the movement a simple wiggle or a waggle or is it more complex.

Is the key just a movement or is it more of an impulse much like a good Karate chop and does this action help get the pedal over the top of the stroke.

The way to measure is not eyeballing a power meter. One really should look at W' in joules when climbing a real hill of 3-5 minutes in duration. If W' is higher on the MBB, it supports Jim's results as I am sure it would.

 

[trplay]

Is the movement a simple wiggle or a waggle or is it more complex.

Is the key just a movement or is it more of an impulse much like a good Karate chop and does this action help get the pedal over the top of the stroke.

yes more medium slow or perhaps karate chop like depending on the speed. If you look close in the Maria climbing video you'll see she is actually almost tracking straight along the fog line not zig zagging. She zig zags when cars are approaching from both ways which is something most of us will do when climbing hard and see danger coming. That is entirely different.

 

[paco1961]

Just wondering how long you two would go at it. Very entertaining.

To a non physics/engineering guy it seems that swinging a DF back and forth during a climb would take the arc of the crank arms along a significantly longer path than is reasonably possible w a little CB boom wag. And it seems like that arc is what creates any possible advantage. Or has the tree guy completely missed the point?

 

[Balor]

Everything being *equal*, longer path means more work. Higher cadence as well... provided you are limited by amount of *force* you can produce.
But like Osiris mentioned, there are practicable limits as to how hard you can apply upper body power.

On the other hand, he might simply be not too stable on Vendetta and swinging the boom too hard leads to overcorrections due to flop and steering inertia! I haven't thought about that, and it explains his 'all over the road' comment really well!
Since my boom is much shorter, I have zero flop and much more trail force, I can swing the boom with much greater speed and force and retain enough control over the process.
Much more experienced Vendetta riders can use the dreaded leg steering (that I cannot manage) for those purposes.

All in all, Osiris, I'm sorry, but the problem *so far* indeed seems to be lack of technique on your part, and I've listed exact reasons why. Yea, my bent is better for that indeed, but given enough experience I bet you would manage that as well - you'll have to swing the boom harder and faster to get a 'statistically measurable' effect.
I've described what numbers what you should look for. Since you have a stronger upper body than I do (not hard to, really), once you'll get comfortable with MBB platform enough I bet you'll see some benefit - which is not HUGE, definitely not hundreds, but tens of watts to be sure.

 

[Balor]

P.S.
"Backswing" of the boom, while may not directly contribution to propulsion, might have 'oval chainring' effect and further contribute to *more effective* leg power delivery and efficiency. That's a theoretical, but a certainly valid point if you ask me.