Wondering what the difference between power cranks and rotor cranks are? Theory behind them, how they function, how they compare to one another ect. Thanks Norm.
The difference between Rotor Cranks and Powercranks
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 10,800 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 point. This elimination of the dead point allows the rider to produce more wattage and lower his/her lactate threshold. The extra wattage is converted to speed in the amount of 2-3 minutes per 40k.
The dead point of conventional pedalling is the void that occurs when the pedals are vertically positioned (one at the top and the other at the bottom), which is a moment at which neither leg can transmit any power.
The dead point limits the cyclist’s performance, causes tendonitis and injuries to the knee, as well as discontinuity in the traction. Rotor System provides the definitive solution to this inefficiency, which is typical of conventional pedalling, by definitively eliminating dead points.
Rotor makes the cranks independent in such a way that they are not aligned at a fixed 180º, but rather the angle between them varies during the cycle in such a way that one pedal never coincides with the one below, thus avoiding power vacuums. Such an effect is achieved by the use of independent cranks that are synchronised by means of an exocentric axel and two rods, which vary the development during the cycle and adapt to the muscle power of the legs at all times. By eliminating the dead point, Rotor optimises the effort of the cyclist and reduces the risk of injury, providing a notable increase in performance and more comfortable and healthy pedalling.
The Benefits provided by Rotor System By eliminating the dead point, the Rotor system maximizes performance, as shown by scientific studies carried out by prestigious international universities. The results demonstrate that Rotor achieves a real increase in power of up to 16% (equivalent to an average advantage of 2-3 minutes in an hour), as well as a reduction in lactic acid and cardiac effort.
a) Reduction of lactates: Rotor reduces the concentration of lactates in the blood thanks to greater muscular efficiency, thus reducing fatigue.
b) Reduction of cardiac effort: Consequently, as a result of the reduction of lactates in the blood, cardiovascular demand is less.
c) Reduces knees injuries: Conventional pedalling subjects the knee to great articulatory stress when the leg is pushing on the upper dead point. By eliminating the dead point, Rotor reduces the typical knee injuries of the cyclist, due to less stress on the knee tendon. Thanks to the variation of the development during the cycle, the push is more progressive and the articulatory stress is more uniform.
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 point, 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 output, which translates directly to the 2-3 minute per hour speed increase. They are scientifically proven to reduce lactate levels, reduce cardiac effort, and improve the health of a cyclists knees.
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”.
F*ck you and the horse you rode in on.
You wet your pants? Call my office in the morning and make an appointment.
Gary,
The only remaining question on ROTORCRANKS
which I have never seen answered concerns the
gearing. If your normal gearing is 52/16, what gearing is being used by the RC’s (1) from 9 o’clock
to where your main power stroke begins after
12 o’clock and (2) from the start of your main power
stroke to 3 o’clock ?. The 52/16 gearing is being
used between 3 and 9 o’clock.
Unless shifting, your gearing remains constant
.
Unless shifting, your gearing remains constant
Through one revolution each crank will move at
three different speeds, effective gearing can’t be
constant.
It is such a *minute *amount that effectively there is no applicable gearing comparison, meaning that the difference may be so small that you may not be able to compare, directly, a gear ratio - however, multiply this times 10,000 per hour (number of times your legs go through a pedal cycle) and the benefits accrue - quite significantly so
.
Hey Gary,
How are Rotor Cranks different than PowerCam (remember those cranks from the mid-80’s)? The PowerCam cranks also had variable angle between the two crank arms.
i agree a little bit with you, rip van winkle, aka not a pcer, aka rotorcranker.
since i would assume you ride (or rode) rotor cranks, how much faster are you on them than your normal cranks?
sorry now if you mentioned this in one of your other 18,000 posts on power or rotor cranks.
Perfection, I think I see what you mean. Since your downstroke slows down just a little and your upstroke speeds up just a little (when compared to a “normal” crankset), then your downstroke force must “act” like a different gearing to some extent. I think I saw this example posted somewhere on the Rotorcranks site.
I’ll make one up to see if I can explain it, though: If you are in a 52/16, the Rotorcrank will act like a 52/16 at about 1:00, like a 52/15.5 at about 2:00, like a 52/15 at about 3:00, like a 52/14.5 at about 4:00, like a 52/15 by about 5:00, and like a 52/16 by 6:00. On the upstroke, since the pedal spindle is moving more quickly, it is somewhat like having a similarly progressively larger-toothed rear cog along the clockface.
Honestly, I don’t “feel” the eccentricity at all. I do notice that I don’t gear down as often to go up slight hills (I just let the rpms drop to the low 80’s), and that my top cruising speed is higher on Rotorcranks than on regular cranks. But, I don’t feel anything different in the pedal stroke.
I actually raced on Rotorcranks for the first time this past weekend. I shouldn’t have raced at all, because I have been very ill. But, I’d pre-registered, hadn’t run a fever in several days, and had one good trainer/brick workout in on Wednesday, so I showed up. The first hundred into the swim, I knew it was going to be a bad day. Then I aspirated some water…not a good thing for someone that’s been fighting bronchitis. 106th out of 175 from the water. The only thing decent was the bike split. I think I was 34th on the bike…about where I normally finish…but, I noticed the guys I rode near all kicked my tail on the uphills, while I caught and passed them on the flats. I know this was partly because the fellows I rode near didn’t have a disc rear wheel, so I could have been more aero and it showed up on the flats. I don’t really know.
This is not my usual riding style compared to others about my same speed. I usually ride the hills better, and the flats not quite this good. I THINK my overall power was lower (therefore the trouble on the hills), but, I was making more speed than usual on the flats because the Rotors seem to offer a slight advantage over regular cranks. The only way to know would be to have a power meter, or, to ride the same course on a regular-crank bike and compare. Anyway, I had the worst run I’ve had in YEARS, in spite of feeling OK on the bike as long as I didn’t push hard enough to start a coughing spell. 76th on the run. I really felt bad. Oh, well, 57th overall. Had 20 in my AG, I was 8th overall, 4th fastest bike split, 11 out of the water, 12th on the run. Usually, I do better, especially on the run. I just didn’t “have it” today, but, the bike was decent…I think Rotors helped me…but, no proof.
Tibbsy wrote: Stop this thing now! It will lead to nothing! STOP!!!
BwaaaAAHHHAAAHAHAHAAAA!
That’s all from me 
“Awfully strong claims considering that you have NO data to back them up.”
take a wander over to the Science section on the web site, you should find what you are looking for, lots of data - there is also a test being conducted right now that will be published later this year in the Fall 2004 ACSM Journal of Sports Medicine (test by http://www.cooperinst.org/)
.
Want a Worthless sports analogy? OK
Rotorcranks: Football, offset I formation
Powercranks: Basketball, Team USA if Stephon Marbury and Gary Payton played guard simultaneously
It’s probably because there isn’t one. That’s OK by me. I can experiment with them myself, if I find they help me, I don’t care what a study shows. If I find they don’t help me, I still don’t care if a study shows they are effective in 99.9% of the cases. I only care if they help me.
BTW, you really might like to try Rotorcranks…they make your extensors work harder per stroke…one of the things you keep saying is proven over and over to be a good strategy for better bicycling performance. Unlike PowerCranks, that can make you suffer like a borrowed mule until you get acclimated to them, (and then they can STILL make you hurt!) Rotorcranks are very easy to adapt to, and shouldn’t interfere with your normal training.
Actually, if, by encouraging your extensors to recruit more muscle fiber units per revolution (which is one thing I think they may do), they could possibly help your performance if you went back to regular cranks! No one else has suggested such…just an idea…you might be able to get the same training effect by just doing bigger gear riding. You wouldn’t have the mechanical advantage of the Rotor system…but, on Rotors, you might avoid some of the knee pain commonly associated with big gears, because the time of slowest foot-speed in the pedal stroke is at a knee angle that may be easier to tolerate…instead of having to push that big gear all the way from the top.
Hard to say…it’s still a new product. Although it may be without peer-reviewed scientifically proven “facts” about it one way, or the other, I’m happy to be a guinea pig!
Gary, I think that is the best job you’ve done so far comparing Rotorcranks and PowerCranks. Dr. Day, I’m not saying Gary’s post is how you would have compared the two products, but, it noticeably lacked negative comments about PowerCranks…that’s a good thing.
They are different products, with different focal points of action in the pedal stroke, and they are both trying to offer athletes a benefit in performance. Both offer guarantees to protect the athletes that opt to try them. I think both products can stand on their own, and both offer advantages. The advantages in performance can vary from athlete to athlete, and even be abscent in some athletes…the jury is still deliberating!
If you are an athlete that needs hard science from a well-known peer-reviewed journal in order to think that there could be any benefit to either/both products, stay away from both of them. If you don’t mind being an experiment of one, with a time guarantee on each product, maybe either/both are appropriate for you.
The dead point of conventional pedalling is the void that occurs when the pedals are vertically positioned (one at the top and the other at the bottom), which is a moment at which neither leg can transmit any power.
=====================================
It is not only at the dead point 12-6 o’clock that a
rider cannot apply power to chainwheel, it is in an
area from 3 mins to 12 until 3 mins after twelve.
Rotorcranks enable a rider to compensate for only
a quarter of this area and for that he needs to adjust
his pedaling if he wants to get maximum benefit.
The Benefits provided by Rotor System By eliminating the dead point, the Rotor system maximizes performance, as shown by scientific studies carried out by prestigious international universities. The results demonstrate that Rotor achieves a real increase in power of up to 16% (equivalent to an average advantage of 2-3 minutes in an hour), as well as a reduction in lactic acid and cardiac effort.
a) Reduction of lactates: Rotor reduces the concentration of lactates in the blood thanks to greater muscular efficiency, thus reducing fatigue.
====================================
How does using the leg muscles in exactly the same
way but with a slightly higher gear improve muscle
efficiency. Any improvement in power comes from the fact that used correctly, RC’s make it possible to
start your pedal stroke the slightest bit earlier than
with normal cranks. That very small amount of
extra power (applied before a normal cranker can
start his pedal stroke) multiplied by 10000 is where
the RC’s advantage lies, and that is only when they are used in the correct manner.
RVP wrote: Ah yes - the old “I don’t care what research shows, I’m an experiment of one” position. It certainly sounds good on paper, but all it says to me is that you must have a very low standard of proof for what works and what does not. Suppose there were a study showing that Rotorcranks did not increase power output - why would you believe that your body is so special that they work for you but not for the study subjects? Or, suppose that there were a study showing that they did increase power output, yet you could not detect one yourself - why wouldn’t you just assume that your measurement technique lacked the same sensitivity as the investigators?
Here we go again…
Look, Sleepy-head, THERE IS NO PROOF at the moment that meets the scientific, peer-reviewed, repeated by other experimenters, and published in leading, respected, well-know journals of science kind of proof. IF there were such proof, and that proof found NO benefits to either of these products, certainly I wouldn’t waste my time with either of them.
In light of the abscence of such data, I am on my own. As such, I have to judge the benefits/lack of benefits on my own. If I find a benefit seems to have occured, it requires at least a stopwatch to verify…because “feel” can fool. I rejected a well-known wheel based upon my stopwatch, and other observations. Lots of people race it and swear it’s “Great!” I didn’t find it to be so. I rejected the anecdotal reports and company-generated data, because it did not show me any benefits…in fact, it proved to perform inferiorly to a 32 spoke Mavic Open Pro wheel, at least on my bikes. I am basically an optomistic person, but, I’m not a fool.
It ain’t a perfect system, but, I think it’s far better than denigrating anything that doesn’t sit “just right” with a notion based upon a biased belief that “everything is probably known about it all already”. I’ll bet my last penny that you do not “know it all”.
Perfection, besides the possibility that all of the Rotorcrank’s benefits (if they exist…happy, RVP? ) are due to being able to begin the downstroke earlier, there may be another possibility to explain why the rider may be produce less lactate at a given workrate…the biomechanical efficiency of the knee/hip might be significantly better during the 2:30 to 4:30 area…where the downward pedal is going slowest…compared to having a constant pedal speed all the way from the top to the bottom.
IF this increase in biomechanical efficiency exists (any biomechanical specialists out there that would be willing to address this possibility?), a cyclist might have a lower lactate production at a given workload.
Perfection, besides the possibility that all of the Rotorcrank’s benefits (if they exist…happy, RVP? ) are due to being able to begin the downstroke earlier, there may be another possibility to explain why the rider may be produce less lactate at a given workrate…the biomechanical efficiency of the knee/hip might be significantly better during the 2:30 to 4:30 area…where the downward pedal is going slowest…compared to having a constant pedal speed all the way from the top to the bottom.
IF this increase in biomechanical efficiency exists (any biomechanical specialists out there that would be willing to address this possibility?), a cyclist might have a lower lactate production at a given workload.
The pedal is slowest from 2 mins past 12 o’clock to
3 o’clock. From 3 o’clock to 9 o’clock it uses the
normal gear setting. That is one of the disadvantages with the RC’s, the compensation for
that portion of dead spot area has to be done in an
area of the pedal stroke that does not normally
produce the most power.
If RC’s were used with the linear pedaling style where main power application starts at 11 o’clock and
ends at 5 o 'clock, you would be using the RC effect
in the strongest area of your power stroke and
not only would you be making maximum use of the
dead spot area, you would also be compensating
for the power you never lost in that area. Now that
is a real power gain.