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You know you're bored when (yet more PC)
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You know you're bored when you are reading U.S. Patents online, but I wanted to read Frank's and get more info on the history of PCs. Ya know, I'm not anti-PC, I just like riding non-PC equipped bikes. Anyway, very interesting stuff:

http://patft.uspto.gov/...&RS=PN/5,860,329

One thing I wonder about is the following claim ,which if I am reading it right, states that if a rider unweights the opposing pedal he will increase the power to the wheel by 50%. Is this right? :

"Experiments measuring the amounts of these forces show them to be substantial. Using representative data (found in FIG. 1) the losses due to the failure to completely unweight the pedal on the recovery phase of the stroke can be calculated. Using this data, if one could simply eliminate these "negative" forces on the pedal during the upstroke (see FIG. 2) the power throughput to the wheel would be increased 50%. Therefore, while the traditional power transfer system is simple and, generally, considered to be reasonably efficient, substantial internal losses are present. "
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Re: You know you're bored when (yet more PC) [Gary in SD] [ In reply to ]
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Blah, Blah, Blah...Gary, your PC obsession is really starting to sound like a lot of sour grapes.

Haim

-------------------------------------------------------
"Sometimes you need to think INSIDE the box!" -- ME
"Why squirrel hate me?"
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Re: You know you're bored when (yet more PC) [Haim] [ In reply to ]
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Results would be even more interesting if experiments were done when riding out of the saddle,
there is a very noticeable increase in power when the
pedal is unweighted in the out of saddle position.
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Re: You know you're bored when (yet more PC) [Haim] [ In reply to ]
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no, no, I find that the claims here can be applied to non-PC equipped bikes as well if the rider unweights the opposing pedal, thats all
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Re: You know you're bored when (yet more PC) [perfection] [ In reply to ]
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wow, for once I agree with perf! :-)) gotta be the new year :-)

indeed, out of the saddle, there is a clear jump in power with the PC. to power up short hills on the PC is a lot of fun (except when you start on them and miss the stroke once in a while, ending smashing your cojo.es on a very comfortable seat SLR 135g)...

btw, anyone here using one? I am the only one catching his bibs on the nose of the seat?
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Re: You know you're bored when (yet more PC) [Gary in SD] [ In reply to ]
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Gary,

Sorry if I misconstrued the intent of your post.

Haim

-------------------------------------------------------
"Sometimes you need to think INSIDE the box!" -- ME
"Why squirrel hate me?"
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Re: You know you're bored when (yet more PC) [Gary in SD] [ In reply to ]
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Gary,

This is very simple to prove to yourself. Sum up the tangential forces shown around the circle then sum up only the positive ones and see the difference. The power increase will be the same if you can do it on regular cranks. But, there lies the rub, learning how to do it on regular cranks.

Frank

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Frank,
An original Ironman and the Inventor of PowerCranks
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Re: You know you're bored when (yet more PC) [Francois] [ In reply to ]
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I am starting to understand the training benefits of PC's. However, I still don't understand how pc's could be faster by themselves, like why you would want to race with them. Isn't there any momentem benefit of of nonPC bikes recovery stroke that is non-existant in PC's.

Please advise.
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Re: You know you're bored when (yet more PC) [Frank Day] [ In reply to ]
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Thanks Frank,

I noticed that "unweight" was the key word used in the patent description. Does this basically mean that just unweighting the pedal, without applying and positive upwards force to lift the pedal, will result in the 50% increase in power?

If a user is trained on PC's to pull up just enough to unweight the opposing pedal during the recovery stroke, will this user actually increase overall power to the drive wheel simply by NOT applying any positive or negative power?

This would allow more effort to be focused on the downstroke, would it not?

Have you ran into this?

Thanks
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Re: You know you're bored when (yet more PC) [Buzzy] [ In reply to ]
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There is no "momentum" benefit from regular cranks. the reason people are starting to race on them is the PC's prohibit the rider from back sliding to old pedaling coordination when they get tired, keeping the power up the last half of the race, (which is, probably, the most important half). So until the brain is completely retrained (which, it looks like, may take years), one should be faster on PC's than on regular cranks once one has the base endurance and skills down.

Frank

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Frank,
An original Ironman and the Inventor of PowerCranks
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Re: You know you're bored when (yet more PC) [Buzzy] [ In reply to ]
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PCs by themselves are not faster. the feedback makes you faster.

if when you swim, you have automatic feedback from a device/coach/mirror etc... on your technique, then you swim faster because better technique means faster times.

on the bike the same principle apply, but the device providing automatic feedback does exist: PCs.
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That is correct ... [ In reply to ]
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using the data in tose charts (others may be more or less efficient) simply unweighting the recovery part of the stroke and changing nothing else will result in about a 50% power increase. Now people don't see that right away because lots of other things change also, the big one being cadence. The issue of how much one can actually learn to pull up on the backstroke is the limiter as to how much one can improve. It is why I estimate that the long-term potential of the PC's is a doubling of the power one can achieve without them (which would require pulling up at about 30% of the power that one pushes down using the forces in the diagram). Only time will tell what the full potential is.

The big advance of the PC's is not that they allow you to "be more focused on the downstroke" but that they improve overall efficiency and effort through the entirety of the stroke.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks
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Re: That is correct ... [Frank Day] [ In reply to ]
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Round pedalers and anklers can apply tangential force throughout the

entire 360 degrees when at the lower cadences but because so many

changes in direction of power application during one revolution of the

crank, it becomes impossible when the cadence rises to 90 and above.

Only when tangential force is applied in the same direction at all times

can one be successful in this objective because muscles need to be in the same power application mode at all times.

To do this one concentrates not on applying continuous tangential

force to the chainwheel but instead one has to attempt to apply

imaginary continuous tangential to one of the pedal axles at all times

and as the pedals are continually moving, the overall result is continuous power to the chainwheel, which was Anquetil's secret and

that was why the toes down technique was used.
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Re: That is correct ... [Frank Day] [ In reply to ]
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[reply] ...simply unweighting the recovery part of the stroke and changing nothing else will result in about a 50% power increase.... The issue of how much one can actually learn to pull up on the backstroke is the limiter as to how much one can improve...

I once worked out the average pedal force in a riding scenario, and found it surprisingly small. When compared with the forces due to mass and inertia of the rising leg, it is in the same order of magnitude. I find a 50% improvement believable.

as ordinary cranks? (I can visualise training to lift by using special heavy pedals or ankle weights, but I imagine that would not be too popular an idea.)
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Re: That is correct ... [pedaller] [ In reply to ]
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Oops, chopped a sentence there. The question was whether PCs help train to actually apply force on the upstroke. It seems that beyond unweighting, they function as ordinary cranks.
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Re: That is correct ... [pedaller] [ In reply to ]
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I would agree that the PC's can function as ordinary
cranks but they are also supposed to help a rider to
perfect his entire stroke by forcing him push forward
and down and then pull back and up, but this is
impossible at the higher cadences or is it ?
A question for anyone who has used PC's , how does
the workout operate at cadences between 100 and 150. If they are teaching the perfect stroke, they
should have no problem spinning at 150 rpm.
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Re: That is correct ... [perfection] [ In reply to ]
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perfection says :

"A question for anyone who has used PC's , how does
the workout operate at cadences between 100 and 150. If they are teaching the perfect stroke, they
should have no problem spinning at 150 rpm."

say what ? it is my experience that super high cadences are quite difficult with PC's. if we rely on old lore about spinning this would seem to be distressing. but PC's do not rely upon old lore. PC's demonstrate to the user very clearly that in order to spin like a madman the user must abandon positive forward pressure over much of the pedal stroke. i can spin pretty darn fast and smooth - but PC's have shown me very clearly that in doing so on a conventional crank all i am REALLY doing is relaxing my recovering leg and whipping it around with my driving one. based on clear observation i would now much rather be able to ride a couple minutes at 100 rpm on PC's than 10 minutes at 150 rpm on a convential crank, where my "spin" is really cheating my stroke. the statemnt should be:

"if you think you have developed an effective spin you should be able to duplicate it on PC's - if you can't you are deceiving yourself."

i believe most all riders - especially ones firmly attached to the idea that they already have a wicked spin (as did i) - are to some degree deceiving themselves about their pedal stroke.
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Re: That is correct ... [t-t-n] [ In reply to ]
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ttn wrote: "i believe most all riders - especially ones firmly attached to the idea that they already have a wicked spin (as did i) - are to some degree deceiving themselves about their pedal stroke. "

I could spin at 130 while on rollers Pre-PC. Once I got PC's though, I found out that my smooth spin was due to my right leg moderating the whole stroke. It was smoothing out my left leg's unwillingness (or inability) to get out of the way and get over the top.

I'm only 2 weeks in on PC's, but, I'm almost up to my normal road speed...although not up to normal distance, yet. I'm very happy with what PC's are teaching my legs about pedalling.



Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
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Re: That is correct ... [perfection] [ In reply to ]
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After a year & a half on the PCs, my cadence is virtually what it was before PCs. I have no problem riding at 100+ RPM for long rides. I have even done over 1 hour at 115. My max on PCs is about 135 - about the same as my max prePC.

When I first started on the PCs, my cadence went down to about 65. After 1 year, I could ride about 1 hour in the 90s.

It is a ton of work to increase your cadence, but it can be done.
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Re: That is correct ... [Goatboy] [ In reply to ]
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What I mean is can you get effective chain drive power to the chainwheel by the pulling up action
(excluding the unweighting effect), push forward
and pull back action when pedaling at 90 to 100 RPM. If not it is not eliminating the deadspot area
and making the stroke more efficient throughout its
entirety.
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Re: That is correct ... [perfection] [ In reply to ]
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If you are asking if the power is uniform the entire circumference of the pedal stroke - No, I am still stronger on the down stroke, as I (or anyone else) always will be.

If you are asking how much torque I apply in the different positions of the pedal stroke - I have no real way of measuring this.

If you are asking if I have eliminated dead spots - They are greatly reduced, but no one can completely eliminate them because the down stroke will always be stronger.

If you are asking if I can do 1 leg drills smoothly at 100+ rpm - I can do them on my rollers all day long & it feels smooth to me.

If you are asking if I get power in the top & bottom of the stroke - I believe that my biggest increases have come from these sections of the stroke, and if I want more power for something like accelerating over a hill that is the part of the stroke that I work.
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