Climbing and Sprinting technical talk

Tuloose

Guru
I call the technique I use to go fast on my Silvio "yanking and cranking".
I push hard on the pedals while alternately pulling back on the bars.
This can cause the bike to drift a little from side to side.
Maybe I am using Jim's technique without being aware of it?
By the end of a hard ride I notice some soreness in my hands and forearms.
I am only beginning to discover the capabilities of this amazing bike!
 

Balor

Zen MBB Master
First and foremost, excuse my poor English. Next, my experience with recumbents is limited to a RWD homemade recumbent I've bought this winter and tracked about 3.5 thousand kilometers this season, including a 400-km brevet with about 3k of climbing... (compare to my last year result on DF, and that is chinese carbon rigid niner running SuperMoto 2.35 tires) but I think I've pinpointed the REAL reason what makes recumbents less efficient when it comes to power output.
I'm a natural born maximizer, so my next 'homebuild' will be pretty damn well researched... I've sunk quite a few hours of feverish brainstorming and article-reading into it.
Warning, lots of 'further reading' via hyperlinks!

1. Pedaling angle:
Optimal angle seems to be about 105. More or less seem to diminish your ability to output power considerably... unfortunately, this position is not very aerodynamic, so some sacrifices will have to be made - like being able to 'lay flat' on flats and sit/stand up nearly vertically - on hills, where aerodynamics is not that important. It is possible on a DF bike, and Cruzbike cockpit configuration seems to support that as well (but it may be possible with RWD recumbent too).

2. Power transfer:
I think this is HUGE, and I've yet to see anyone mention that, so here it goes:
For every action, there is an equal and opposite reaction. Unlike gravity, that 'gives back as much as it takes', pushing against your own back (as in 'lower back, heh') tissues and seat padding introduces huge losses into the system, much moreso than 'frame stiffness losses' and the like, I bet my life on that.
Imagine taping large slabs of fatty meat wrapped in seat padding to your feet and trying to pedal! You may actually try to do it, but I don't think that would just be a waste of good food to prove that 'water is wet'. After all, road shoes with carbon-soles are supremely stiff for a reason.

When you counteract this force by pulling on the bars instead of pushing against the seat, you eliminate much of the inefficiency, because our bones and tendons are much more efficient when it comes to tension, unlike our tissues when it comes to compression, as in 'pulling on a rope' vs 'pushing against a sponge'. No contest.

Of course, some mechanical losses would STILL occur as compared to gravity that is 100% efficient, but this is a sacrifice we have to make.

3. Anatomy and cardiovascular system limits.

Since we are not evolved to apply power 'legs upwards', our cardiovascular system may not be up to the task. It is subject to personal variation, of course, and as this very insightful article states, some are affected more than others - as I, myself, found out to much of my chagrin. (Hence, I'll have to do with something akin to Silvio geometry, not Vendetta - less incline, less seat to BB vertical distance).

Anyway, our major veins and arteries that power the legs in the lower back region must suffer some impingement during pushing against your seat as well, hence the problem is further exacerbated (again, subject to variation in personal physiology and seat geometry).

Imagine this as you push down the gas pedal on your car, you pinch down a gas fuel hose that goes right beneath it, effectively limiting your fuel supply to the engine when you need it most! (At least when it comes to the internal iliac veins and arteries).
The dreaded 'numb toes' syndrome that strikes when you push the hardest could be indication of that too.
Effectiveness of 'bridging' must come from removing above mentioned impingements, but power transfer losses still apply, not to mention physical and mental effort of maintaining this position and adaption of ineffective (see 1.) nearly 180 degrees pedaling angle.

Again, this problem is avoided by a cockpit design that allows pulling on the bars instead of pushing against the seat, FWD or RWD notwithstanding (but, of course, FWD is more efficient when it comes to losses in drivetrain).

There is an alternative, of course - counteracting the push by pulling against the contact pedals, but we run full force into the limits of our physiology again, as described in these two articles:
The Myth of the Upstroke
Which Muscles are Really Used During the Pedal Stroke?

First one is especially insightful, because I fully experienced the symptoms described as I tried to 'pedal circles':

• Lower-back pain
• Tightness and pain in the hip
• Loss of power and efficiency
• A feeling of floating or disengagement on one or both legs
• In extreme cases – impingement in the iliac artery!

The 3rd comes directly from the latter - and since our arteries already experiencing impingement (because you can NEVER fully counteract our strongest and largest muscles with much smaller ones no matter how you train them, not to mention the weight we put on them while we lay down in our seat - that may be a problem in itself for heavier riders like I am, for instance) - this solution might be worse than the problem.

Conclusion:
Pulling on the bars instead of pushing against your back or trying to pedal circles avoids all these problems, and most widespread 'hamster' and 'avatar' bars are simply useless for that, and superman bars are only marginally more useful. And far as I understand, none of RWD cockpits are designed for that purpose.

Cruzbike cockpit with road bars (or bullhorns) you can pull against is optimal. My guess that you can emulate that cockpit with RWD design too, but it might interfere with steering, as well as add further complication to drivetrain and some loss of efficiency.

Unfortunately, I'm dirt poor and lack necessary equipment for proper measurement and testing, so I would not mind some R&D money Jim promised sent my way :D.
Anyway, to be serious, I really hope that my efforts and research would be useful, and if they do, I'd love to have Silvio frameset sent my way someday, because I sure as hell will never be able to afford it myself. :(
So far I'll have to manage with a one that is made from steel, lack suspension and likely weight about 40 pounds, but I need something for ultra-cycling that does not kill my butt, back and hands, and 'Cruzbike' seems to be a PERFECT design for the job.

EDIT:

I've spoke with a friend of mine, who happens to be an avid cyclist (not recumbent variety, though) MD and surgeon, so he is quite familiar with anatomy to put it mildly.
He said that, unless you already have some sort of pathology, impingement of veins from recument position is unlikely, impingement of arteries is even less likely, so disregard that.
What I meant as impingement of external veins is already known as 'recument butt', so disregard that too (but still, less pressure - more blood - more power, our glutes are largest muscles in the body).

Everything else stands, though.

As for real possibility of impingement, sciatic nerve is at real risk here, and it can produce similar negative results.
 
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bladderhead

Zen MBB Master
I like that upstroke article. I have been wondering about trying clipless, but he persuaded me to retain my famous patent heel-clips. I am not worrying about the upstroke any more. He seems to think people put their feet too far back on the pedals. I agree. I ride on my in-steps.
 

Balor

Zen MBB Master
I like that upstroke article. I have been wondering about trying clipless, but he persuaded me to retain my famous patent heel-clips. I am not worrying about the upstroke any more. He seems to think people put their feet too far back on the pedals. I agree. I ride on my in-steps.

Well, when it comes to track cycling with crazy RPMs - it is nigh impossible without some sort of retaining system to maintain those without having your feet fly off the pedals. So, it is quite functional from where it came from - namely, track cycling.
Also, clipless pedals come with stiff soles that provide better power delivery... though not that nice to walk upon.
But for road and mountain cycling - clipless does seem to be overrated.

But the 'elephant in the room' - namely, elimination of power delivery losses by removing 'pushing against backseat' out of the equation the the greatest factor by far, I can bet anything.
Also, yet an other very good example how recruitment of upper body contributes to power delivery:


Notice how he nearly ripped off the handlebars in the process (near the end of his trial).
If you try to do it on a vendetta, you can do it. Any other handlebar design - I bet it would be a recipe for disaster even if you manage it.
 

Balor

Zen MBB Master
You might be surprised by how much force I can exert on my raptobike handlebars. I have it setup with a fixed tiller and can really haul on it.

Well, this design seems adequate, but this is no Cruzbike cockpit... and you are no Fostermann, I bet :)
I think that "pistol grips" like ones used by Stanislav Bober might be a good alternative:

But one thing is for sure - tilting praying hamster bars (like I have) you cannot really pull against are a curse upon recumbent society.
By the way, notice how he pulls against them for a much more vertical 'sitting up' position. I guess you can do it too in a way.

Anyway, if you happen to posses a very bony a... back, stringy complexion and custom-made perfectly-fitted hardshell seat with no padding whatsoever (drilled with vent holes, for instance) - it may actually allow you to climb much better than someone with a very similar raw power output, pedalling style and, total weight - but fleshy back and padded seat.
It may explain while some manage to climb like a monkey, and others (like me, who is moderately overweight + ventisit comfort padding) simply crawls up any incline that is more than 1%.
 

DuncanWatson

Well-Known Member
I run a zotefoam pad on my Raptobike and no pad on my Velomobile. I am very excited as my Vendetta arrives on Friday. I have the day off and sun has been pencilled in for the weekend.
 

MrSteve

Zen MBB Master
Once you learn to dance with your FWD MBB uphill, you'll understand.

Meanwhile, here's an anecdote:
I was riding with a small group of local bicyclists and one of them was on a blinged-out Bacchetta on 700c wheels.
No, I can't remember exactly what model, sorry.
The rider was seated in a hard shell seat on a really thick expanded foam pad, if that tells you anything.
We were talking about his arthritis... so we are both old.
I was on my hot-rodded Sofrider.
We started climbing a long, slow, steep hill and I paced the Bacchetta... being a bit sociable and a lot curious.
I was in my normal gear -sort of mashing- and the Bacchetta guy was spinning in a low gear in the third ring.
It was fascinating, watching his back sink into his comfy foam back cushion in time with every pedal stroke.
My back was supported by the standard Cruzbike cushion, true, but the power was between the pedals
and the pocket of the seat (between the seat back and the seat pan.)
I was also using my upper body, while the Bacchetta rider was using only his legs.
At any time I wished, I could have left the Bacchetta behind, spinning up the hill.

At the crest of the hill, the Bacchetta sped away from me.
His advantages were everywhere other than uphill, where my bike held the decisive upper hand.

In fact, no recumbent has ever out climbed me on my Sofrider, not in all the seven years it's been on the road;
now I can handily out climb myself on my Vendetta.
 

VenRiderGuy

Well-Known Member
MrSteve,

I would love to see a video of you on your Sofrider and on your Vendetta as you, on your Vendetta, out climb yourself riding the Sofrider. Cruzbikes are outstanding I know, but I'm learning that Cruzbike riders are even more outstanding.:D:cool:

Take care.....
 

jond

Zen MBB Master
purple is a nice colour :) . cycling prowess in any terrain is a variable feast and a god given ability especially pure climbing. compare cadel evans to me...uhhh lets not okay. clipping into pedals has safety advantages and control benefits for myself. i also note that clipped in i can seemingly vary my pedal style to "rest" my legs from the previous pedal style incarnation. i feel like i can employ 3 types of pedal style as it were with each bringing a refreshed state and no this does not include mashing the pedals. when you add in the ability to shift up and back down the seat pedal style can be further changed adding to effort longevity and recuperation of muscle groups. of course this for all intents and purposes is still just pedaling purple and purely anecdotal. see lots of purple. yet on the trikes the feel is different for me and not quite so varied due to the greater fixed rider position. the df has a few options too stand or seated but is not the option i choose routinely for all it's drawbacks compared to a recumbent. i think the mbb actually assists my knees muscle groups torso core arms with the constant constant changes. perfect bike for me.
 

bladderhead

Zen MBB Master
If you wanted Bober-type, how difficult would it be to make short handlebars? How difficult would it be to fit the levers on? I had a lot of trouble with levers. What about knee clearance?
 

Balor

Zen MBB Master
If you wanted Bober-type, how difficult would it be to make short handlebars? How difficult would it be to fit the levers on? I had a lot of trouble with levers. What about knee clearance?

Shorter cranks are all the rage this days, and would help with knee clearance somewhat.
As for levers and shifters - his configuration is clearly seen on the video.
However, 'cruzbike' cockpit is definitely superior, and cannot be easily emulated on a fixed boom bike, because it would likely interfere with steering (since your legs do not pivot with the steering).
 

ReklinedRider

Zen MBB Master
If you wanted Bober-type, how difficult would it be to make short handlebars? How difficult would it be to fit the levers on? I had a lot of trouble with levers. What about knee clearance?

Take a look at the Amateur Aerodynamics thread and look at Jim Gerwing's handlebar evolution. Similar to Bober's (i think).
 
Let's pretend for a moment that we take a vendetta to the bottom of a hill and put a seat on that gives you support sitting up. Would that help with the hill?
If the answer is yes, why not a spring loaded seat base that can pop up and lock into place behind you on climbs and be unlocked to lay back when not climbing?
 

Balor

Zen MBB Master
Let's pretend for a moment that we take a vendetta to the bottom of a hill and put a seat on that gives you support sitting up. Would that help with the hill?
If the answer is yes, why not a spring loaded seat base that can pop up and lock into place behind you on climbs and be unlocked to lay back when not climbing?

Your seat to pedal distance will change too.

But enter Android, FS FWD MBB, made by Josef:
https://www.flickr.com/photos/55312338@N04/sets/72157625273891548/
http://velorizontal.bbfr.net/t12525-russian-full-suspension-fwd-mbb-recumbent-android

He claims that having a more vertical seat indeed makes climbing easier. But since this version has underseat steering, I doubt that it can be very efficiently utilized for pulling. (Also, it weights nearly 100 pounds, lol).
By the way, he later added 'on the fly adjust ability', but unfortunately this (along with this Zockra-inspired foldable MBB) recumbent was left in Ukraine when he moved to Russia and are unavailable right now, most unfortunately.

This new version is much lighter and faster, though lacking in adjustability.
http://velomobile.org/forum/viewtopic.php?f=108&t=12881
 
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Balor

Zen MBB Master
Also, it is not a matter of back support per se. Remember, to avoid power transfer losses you should not be using you seat back as support, preferably at all!
 
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