Difference between Rotor Cranks and Powercranks - explained

Triathlon Forum
1

After many questions, I decided to write this very brief explaination of the difference between Rotor Cranks and Powercranks. I believe that it is fair and balanced, as I see benefits to both systems:

What is the difference between Rotor Cranks and Powercranks?

http://www.rotorcranksusa.com/images/newrs4.jpg

How Rotor Cranks work - and the benefits:

Rotor Cranks work by increasing the force required on the drive side crankarm which propels the non-drive crank are past the 12 o’clock point … also known as the dead spot. This happens 180 times a minute in a 90RPM ride. Or 38,400 times an hour. The cyclist is now “permanently pushing” the cranks as there is no gap between when the legs take over push/recover duties, otherwise known as the dead spot. This elimination of the dead spot allows the rider to produce more wattage at his/her lactate threshold. The extra wattage is converted to speed in the amount of 2-3 minutes per 40k.

http://www.sportdiagnosen.de/modules/sections/images/powercranksstart.jpg

How Powercranks work - and the benefits:

PowerCranks teach your neurologic system to unconsciously “pedal in circles.” By pedaling in circles, more of the energy you are now expending actually gets to the wheel. For the same overall effort, the more efficiently you pedal, the faster you go. So the cyclist gets more efficient use of the muscles he/she has already trained and, as noted above, the ability to incorporate new muscle mass into the now unused portions of the pedal stroke. Powercranks are based on “pulling” up on the pedal stroke using the weaker hip flexor muscles. Unlike normal cranks, each crank arm spins independently of one another.

Difference between Rotor Cranks and Powercranks:

Rotor Cranks eliminate the dead spot, allowing for “permanent push” to the pedals, making legs efficient at what they do best: pushing. This allows for lowered lactate levels and increased wattage at LT, which translates directly to the 2-3 minute per 40k speed increase. They are scientifically proven to reduce lactate levels, reduce cardiac effort, and improve the health of a cyclists knees by eliminating the dead spot.

Powercranks gives you an immediate feedback system as to when you start to pedal improperly so you can retrain your neurological system to fire your muscles in a different coordination changing the pedaling dynamic to improve pedaling efficiency. They are great for developing a smooth and efficient spin and are a much better alternative than one-leg pedaling drills. They improve the strength of hip flexor muscles which benefit running and “lifting the leg”.

2

Gary,

I write this with trepidation because I don’t want to get into a RotorCranks vs PowerCranks debate.

A couple of points. Rotors DO NOT eiiminate the dead spot if the dead spot is defined as negative force on any of the cranks at any point of the circle. They do, however, modify the dynamic of the “dead spot”.

This is how I see the difference between the two products.

RotorCranks try to maximize the output of the engine that the rider already possesses, regardless of whether the engine is regular cranks or PowerCranks trained.

PowerCranks improves the engine beyond what can be done training on regular cranks or RotorCranks. In addition, the engine “improvements” carry over to running also.

I think the difference is that simple.

3

Another difference: Powercrank training WILL HELP your efficiency when you are riding regular cranks. Rotorcrank training will NOT help your efficiency when you are riding regular cranks.

Being a triathlete, and therefore seeking run improvement along with biking split improvement, PowerCranks are a no-brainer if you are talking about the benefits of one over the other. I don’t think anyone has suggested that Rotorcranking will help the run at all.

However, I really see a use for both systems…PowerCrank training to increase efficiency by incorporating more muscle and improved neuromuscular timing to produce power and/or eliminate the “drag” or “negative pressure” (or whatever term makes sense that describes the force required by the extensors to lift the leg/pedal/crank of the rising leg in a “non-trained” pedal stroke), and Rotorcrank training to get the most benefit possible from those already hard-working extensors.

It would be interesting to be able to do both. Right now, I’m having trouble making enough time to PC…and, like I said before, if I only have time (and money) to do one, I’d pick PC’s for triathletes. Time Trialists may disagree, if for no other reason but the biking results of Rotorcranking seem to be quicker coming compared to biking results of PCing…but, there’s always the run in triathlons, and run benefits of PCing are quicker coming than the biking benefits of Rotorcranks.

4

Seems to me, based upon these opinions that the way to go is train on PC’s and race on RC’s.

5

Gary:

You can probably except a summons and complaint from Fox News for using their trademarked slogan “Fair and Balanced”

Oh wait… they lost that lawsuit. Nevermind

6

Of course, you’d still have to train on RC’s, too…just probably not nearly as much time as on PC’s.

I rode PC’s 90-95% of the time and had no problems going back to regular cranks for my races. In retrospect, I wish I would have raced one very hilly race on my PC’s…those of you that train on them probably know what I’m talking about…you really get up the hill faster. I just couldn’t trust myself to not tire my hip flexors out on the long flat sections where there is no rest.

Although I don’t know how much time you’d need to spend training on RC’s in order to race on them…Gary’s got a good guess. The big question is the effect on the run…I don’t think RCs would hurt the run…but, I don’t know. If RC’s don’t hurt the run, but simply help efficiency on the ride…it’s a good strategy to race on them.

However, overall, for triathletes, PC training scores big on the run benefit alone. The biking split benefits are good, too, but take just a little longer to realize.

7

Should Rotor Cranks be UCI legal?

Here are the pertinent UCI regulations -

"SECTION 2: BICYCLES
Preamble

Bicycles shall comply with the spirit and principle of cycling as a sport. The spirit suggests that cyclists compete in competitions on an equal footing. The principle asserts the primacy of man over machine."

"Propulsion

1.3.008 The bicycle shall be propelled solely, through a lower bracket, by the legs moving in a circular movement."

As Gary has made clear, the rotor cranks are a device (machine) designed to overcome the most difficult part of pedalling a bicycle. Does this violate the man over machine principle?

It might also be argued that rotor cranks enable the legs to move in other than a circular motion? At least they definitely aid the legs in moving in a circular motion.

Currently Rotor Cranks are UCI legal, but have they ever been ridden in a major race, such that they would cause UCI review?

Would you consider it fair, if Lance loses the Tour Time Trial to a rider using Rotor Cranks?

The intent of Powercranks is totally different than Rotor Cranks. As stated they are a training device to help you ride a regular bike faster.

I don’t know if Powercranks have received UCI approval.
Frank thinks some people will actually be faster with the Powercranks as they enforce maintaining a more efficient circular pedal stroke. By forcing the legs to move in complete circles they adhere to the UCI principles. They also do not aid the legs in moving thru the circle in any way.
As Frank emphasizes, the purpose is to build a better engine, and you are the engine.

Is the idea of racing to see how fast we can go or to see how fast we can make our engine? With wheels, bars, frames etc, this isn’t such a simple question.

But by helping the legs get thru the hard part of pedalling are the Rotor Cranks different from the aid received from aerodynamic wheels?

My intent isn’t to so much to slam Rotor Cranks as to get into a discussion about the goals of training and competing.
Here I think there is a difference between the average age grouper and pros.

Pros need to win to make money. Most of us are really only competing against ourselves.

If you ride 2-3 minutes faster with Rotor Cranks, (which I am not doubting), would you have the satisfaction of knowing you made yourself a better athlete? Does it matter to you?

8

Should Rotor Cranks be UCI legal?

Here are the pertinent UCI regulations -

"SECTION 2: BICYCLES
Preamble

Bicycles shall comply with the spirit and principle of cycling as a sport. The spirit suggests that cyclists compete in competitions on an equal footing. The principle asserts the primacy of man over machine."

"Propulsion

1.3.008 The bicycle shall be propelled solely, through a lower bracket, by the legs moving in a circular movement."

As Gary has made clear, the rotor cranks are a device (machine) designed to overcome the most difficult part of pedalling a bicycle. Does this violate the man over machine principle?

It might also be argued that rotor cranks enable the legs to move in other than a circular motion? At least they definitely aid the legs in moving in a circular motion. No, the pedaling is exactly circular, what changes is the force applied to the pedals theroughout the pedal rotation - more is applied on the downstroke and less on the upstroke.

Currently Rotor Cranks are UCI legal, but have they ever been ridden in a major race, such that they would cause UCI review? Yeah, the Giro and Vuelta last year, and this year as planned, and the Olympics in Athens for 04
Would you consider it fair, if Lance loses the Tour Time Trial to a rider using Rotor Cranks? Absolutely, as fair as if Lance won a time trial because of his custom “one off” aero Giro helmet or custom aerobars.

The intent of Powercranks is totally different than Rotor Cranks. As stated they are a training device to help you ride a regular bike faster.

I don’t know if Powercranks have received UCI approval.
Frank thinks some people will actually be faster with the Powercranks as they enforce maintaining a more efficient circular pedal stroke. By forcing the legs to move in complete circles they adhere to the UCI principles. They also do not aid the legs in moving thru the circle in any way.
As Frank emphasizes, the purpose is to build a better engine, and you are the engine.

Is the idea of racing to see how fast we can go or to see how fast we can make our engine? With wheels, bars, frames etc, this isn’t such a simple question.

But by helping the legs get thru the hard part of pedalling are the Rotor Cranks different from the aid received from aerodynamic wheels? Yes, much as the derailleur has helped cyclists, and aerobars, Rotor Cranks make the rider more efficient.
My intent isn’t to so much to slam Rotor Cranks as to get into a discussion about the goals of training and competing.
Here I think there is a difference between the average age grouper and pros.

Pros need to win to make money. Most of us are really only competing against ourselves.

9

Maybe I don’t understand, the Rotor Crank mechnism but I thought that you wouldn’t so much increase the force on the downstroke but rather the mechanism of the cranks eliminates some of the force needed to pull the pedal up. This enables more of the downstroke force to propel you forward.

The cranks don’t enable you too actually exert greater force, you need to get stronger for this to happen. They enable the application of more force.

So a mechanical device is enabling you to apply greater force.

While the Rotor Cranks aid and create mashers, does their effectiveness actually undermine the proponents of mashing and support Frank’s advocacy of circular pedalling? The less force needed from the downstroke to push the other pedal up, enables greater forward force to be applied on the downstroke.
Powercranks teach you to do this without the aid of a mechanical device.

10

i am definitely of the opinion that if RC’s start turning up with a noticeble regularity and visibilty at big-time uci events they will be banned.

some skinny-a$$ spanish dude beats jan and lance while RC-ing and what do you suppose the story will be? the cranks, and the mechanics of the cranks. no way in hell will uci sit by and watch something as - sorry gary - obviously, or at least - impressionably gimicky as RC’s take center stage over the athlete.

verbruggen banned non diamond frames for less reason, saying " bicycles should look like bicycles, not like aeroplanes".

how do the rube goldberg-esque loking RC’s compare to that? RC’s, if they actually do what they say, are their own worst enemy insofar as big-time pro use is concerned. nevermind the rules, they will simply write a new one regarding the mechanics ( or lack thereof )of mechanical leverage aides within the crankset, or somesuch. easy.

mind you, i am not saying this would be the right thing to do, or a good thing to do, or anything of the sort. i am predicting this is what they WILL do, should RC grab any significant cycling headline. of this i have zero doubt.

11

well, that is not exactly true. as a matter of fact i outright liied up there. :slight_smile: i find them distasteful. with them, you are no longer actually bicycling, imho. may as well be lying down in a recumbant, pulling on some stupid arm levers or something.

it is, admittedly, a fine line. and, they appear to be a good idea, well executed. but, they also go over the line of what to me constitutes pedalling a bicycle. time will tell if others feel the same way. but, i truly cannot see cycling’s governing bodies letting these thing determine race results, or even appearing to do so. the sooner they are banned, the better insofar as pro/elite level competition is concerned.

whether or not some local schmoe wants to use them to win the podunkville tuesday nite tt … whatever. but, if they get banned at the higher levels i do think the appeal of that will diminish.

one man’s opinion, obviously. :slight_smile:

did i say “sorry, gary” yet?

12
  1. Is the Rotor System authorized for official competitions?
    The Rotor System was authorized by the UCI (International Cycling Union)** for professional road bike competition in October, 2000**. The Rotor System fulfils the criteria presented in the UCI rule:

Art 1.3.010 UCI: “The bicycle should be propelled solely, through a chainset, by the legs moving in a circular movement”.

In Triathlon competition, use of the Rotor System is permitted:
a) Olympic Distance: ITU reference to the decisions of the UCI.
b) Long Distance: There are no types of restrictions on materials used.

Authorization for use of the Rotor System in Mountain Bike competition was obtained in 1998 and these athletes continue to use the Rotor System with success.

**You see, the UCI is fully aware that Rotor Cranks exist, they have tried them out in tests and given them their full blessing. Rotor Cranks are not magic, just more efficient, such is a dreailleur. Like the derailleur, it allows the cyclist to apply power how and where needed. **

The UCI is nothing to be concerned about,

Did the UCI ban Mavic Mektronics, radios, electronic shifting, or SwiftSkin suits? No.

Don’t be paranoid!

14

Kraig,

While wandering about your site after wondering about the possibilites of combining Red Brand shoes with either PC’s or RC’s I came across your power vs cadence chart,which I found interesting.

http://www.biketechreview.com/power/ptsampling.htm

Power was maximum at a cadence somewhere between 60 and 70 and dropped off above 70. This seems in accordance with most of the studies and would support my reasoning behind why RC’s work (lower effective cadence (pedal speed) during power phase). Any comments?

15

gary.

uci ALSO used to allow spinacchi, non-diamond frames, little cables holding you to the front on the bike, paddle-style seats, etc. they changed their minds.

the current line is something like: if the new innovation proves to safely add to the sport, it will continue to be allowed" pretty vague.

as a guy with a vested interest in seeing them succeed i can see how you would think they are similar to the deraileur. but, think again - the deralleur ADDS to cycling, in that the rider can ride more terrain. mektronic added, in that it just did an existing thing a little differntly. etc.

RC introduces a wholly new mechanical leverage into the basic action of pedalling a bicycle. there is ample target for a new rule to address ( and ban) them thru their own uniqueness. there is ample precendent. provided they actually do what you claim, i really think it only a matter of time.

i’ll say again - some second rate guy wins criterium internationale on these and they will be gone. even a first rate guy - just no way uci is gonna let these things take the stage. for God’s sake, if you want the hour record you have to ride a merckx - like bicycle. do you really think the guys who came up with THAT are gonna have races won on a leverage device crankset ?? no freaking way.

16

Frank,

Good comparison… but, one question. Both products make claims to knee injury avoidance capacity. What is the bio-mechanics to this issue? I have been waivering between buying one or the other based on knee injury prevention qualities. Is there a difference? Or, do both work on the same “injury prevention” biomechanical reasoning?

Joe Moya

17

I don’t have a clue why RC’s would make the fewer knee injury claims, especially since they do the exact opposite of what the PC’s do that cause us to make our claims.

PowerCranks makes that claim for several reasons.

  1. In cycling, they reduce the stresses on the knees by spreading the power out over a larger portion of the stroke. This would be helpful for those with chondromalacia or other knee problems where increased pressure or force aggravates the problem.

  2. In runners, knee injuries have been shown to be associated with muscle imbalances. PC’s correct those imbalances and, therefore, should reduce knee injuries. (This is unproven but is a reasonable anticipated result).

  3. PC’s are now being used in some rehabilitation centers in preference to regular cranks to improve knee rehabilitation.

18

Thanks for 3mins of skepticism and 1min of ROTFLOL :-)))
.

19

Joe, I can’t attest to rotorcrank’s effects on knee pain. I can tell you that after I was instructed to lower my cadence to get a faster time trial time (I really WAS faster at a cadence of 80-83 instead of 95-100…something I could hardly believe until I saw the results over and over), it had the bad side effect of knee pain. Therefore I saved my lower rpm riding for the time trial only. Getting on PC’s, I dreaded the return of knee pain, because I had to drop my cadence so much lower…but, lo and behold…it never returned. Never had so much as a twinge at cadences as low as 65 and pushing hard.

20

<<there is ample target for a new rule to address ( and ban) them thru their own uniqueness. there is ample precendent. provided they actually do what you claim, i really think it only a matter of time.

i’ll say again - some second rate guy wins criterium internationale on these and they will be gone.>>

You are probably right, but it will most likely be because Shimano and Campagnolo will exert their (i’m guessing) considerable influence with the UCI if they are not able to create a comparable product.

Haim