Rotor elliptical cranks

London knight said:

😕 One of my teammates recently installed rotor elliptical cranks on his roadbike in an effort to improve his timetrialing (ie. removal of the deadspot when pedalling). I was wondering if there is any evidence that these type of cranks can improve performance?

Here we go again! 😄 Tyson

I take it this has been a topic on old forums?

London knight said:

😕 One of my teammates recently installed rotor elliptical cranks on his roadbike in an effort to improve his timetrialing (ie. removal of the deadspot when pedalling). I was wondering if there is any evidence that these type of cranks can improve performance?

In short, yes, but not because of the removal of the dead spot per se, but because of the reduction of its negative effects.

This is a reasonable explanation/hypotheses for the fact that "pedalling circles" does not improve performance, but Q-rings and cranks DO.

Teaching yourself to spin in circles and pull up with normal rings REDUCES efficiency as your hamstrings are forced to create more force than they want to, i,e this technique INCREASES the demands on the hamstrings, which are forced to recruit type 2 fibres and then deplete glycogen and create lactic acid.

Q-rings and Rotor cranks INCREASE efficiency and decrease lactate production because they REDUCE the forces needed to be produced by your muscles during the deadspot, ensuring mostly type 1 fibres, which are more efficient, are capable of producing the forces demanded.

It is a legacy of the failed Biopace rings and a tradition of weight obsession which has restricted the uptake of this technology, which IS performance enhancing. See the Rotor websited link to published studies:

rotorbike.comscience.htmOpen ↗

11ring said:

This is a reasonable explanation/hypotheses for the fact that "pedalling circles" does not improve performance, but Q-rings and cranks DO.

There is no direct evidence to support this claim.

acoggan said:

There is no direct evidence to support this claim.

The study below found a significant increase in maximal power outputs and ability to sustain high intensity aerobic efforts in cyclists using Q rings as opposed to round rings. There are also other published works which suggest a performance enhancing effect from their use.

rotorbike.comq ring study.pdfOpen ↗

I am not aware of any such study which shows any improvement through changing the way that force (torque) is applied through the pedal stroke using round rings.

11ring said:

The study below found a significant increase in maximal power outputs and ability to sustain high intensity aerobic efforts in cyclists using Q rings as opposed to round rings. There are also other published works which suggest a performance enhancing effect from their use.

rotorbike.comq ring study.pdfOpen ↗

I am not aware of any such study which shows any improvement through changing the way that force (torque) is applied through the pedal stroke using round rings.

Allow me to be more specific: there are no published studies showing that Q rings or Rotorcranks improve performance.

As for this unpublished preliminary report, I find it interesting that power was measured using a Computrainer, which like the SRM ergometer assumes a constant angular velocity when calculating power. Such an assumption obviously doesn't hold when using non-round chainrings, which is why the SRM tends to overestimate power when used with such products - the Computrainer could very well be the same.

acoggan said:

Allow me to be more specific: there are no published studies showing that Q rings or Rotorcranks improve performance.

This may be the case, but that does not mean there is no evidence for a performance enhancing effect, the repeatability of the reported gains across several tests would give the indication that there is reason for further study to quantify and explore the exact reasons for the reported improvements.

As for this unpublished preliminary report, I find it interesting that power was measured using a Computrainer, which like the SRM ergometer assumes a constant angular velocity when calculating power. Such an assumption obviously doesn't hold when using non-round chainrings, which is why the SRM tends to overestimate power when used with such products - the Computrainer could very well be the same.

Regarding the testing protocols, similar preliminary studies on Rotor Cranks found improvements using cateye ergometers and wind load ergometers, so the possibility of the reported gains being the result of a measurement anomaly are slight.

Not sure, but the following seem to be summaries of or actual published reports

rotorbike.comtest univ soria eng.pdfOpen ↗
rotorbike.comtest univ valladolid eng.pdfOpen ↗