Oval Chainrings (Q / Rotorings)

[BikeMax]

Anyone who has been following the other thread should read the bottom of page 44 of this study.

[Bike Tech]

Peter,

 

You say it: it 's not a matter of increased work (of course not) but a matter of improved crank power efficiency. A circular chainring seems to be not the most efficient solution.

[Ivanb]

Great to see another thread again. I'll have some of that popcorn

 

[Ivanb]

haha' date=' wow the other one was over 40 posts wasnt it?! [/quote']

 

300 I think

[Windbreaker]

 

Great to see another thread again. I'll have some of that popcorn

 

So how much you paying to keep this oner going?

 

[Ivanb]

absoloutely nothing just saw it now.

 

Why would I do that or are you jealous i didn't call you LOL

 

 

[Windbreaker]

From the study - "Even with the crank orientated in the optimal position the Q-Ring performances are disappointing and remain very weak."

[1kTT]

Everytime one of the guys in the bunch asks me what I think of my Rotor rings I tell them  they are horrible, terrible, wouldnt ride them if I was paid to do it- in fact am taking them off next week.

 

Then I just smile, put the hammer down on the next climb and listen to the huffing and puffing from behind.

 

Stay away from these things, they are no good at all ;-)

 

 

 

 

 

[BikeMax]

 

From the study - "Even with the crank orientated in the optimal position the Q-Ring performances are disappointing and remain very weak."

 

Not sure Iven B has read this study...

 

[mdk555]

I've also got a question that MDK555 or one of the other tandem fundi's can answer (not you Big H - you just think you know all the answers ).

 

Why aren't the two cranks on a tandem offset by a few degrees - similar to the angle created by the q rings? That would eliminate the dead spot. Or not?

Yep is does help eliminate the deadspot.  In the USA offsetting the cranks by up 5 teeth is very popular and the general feeling is that it does help especially on the climbs however when it comes to racing (and trust me they are big into racing tandems with up to 50 tandems competing on tight 1 - 3 km circuits) not only are the cranks in sync' date=' but they are shortened by up to 5 cm.  I have seen pics of tandems going thru corners that wil scare the living daylight out of all of us and there can be no room for error.

 

Me versus offsetting cranks versus oval rings -  no thanks as it looks very uncool and rather perfect the full circle (push, scape, pull)

[/quote'] Gonna have to eat my words here

[Christie]

Anyone who has been following the other thread should read the bottom of page 44 of this study.

 

This one? http://www.noncircularchainring.be

 

[Ivanb]

From the study - "Even with the crank orientated in the optimal position the Q-Ring performances are disappointing and remain very weak."

Not sure Iven B has read this study...

 

Not Yet, it is quite lengthy. I amreading it.

 

Who is the guy and are you believing 1 study, like you said what equipment and is it reliable blah blah blah.?

 

 LOL

 

Yeah will read and comment and as I have always said everyone is entitled to their own opinions and research.

[BikeMax]

 

From the study - "Even with the crank orientated in the optimal position the Q-Ring performances are disappointing and remain very weak."

 

Not sure Iven B has read this study...

 

Not Yet' date=' it is quite lengthy. I amreading it.

 

Who is the guy and are you believing 1 study, like you said what equipment and is it reliable blah blah blah.?

 

 LOL

 

Yeah will read and comment and as I have always said everyone is entitled to their own opinions and research.

[/quote']

 

Looks reasonably well thought through to me - I do not agree with his findings re oval rings as a whole, but what is clear is that, even if you do buy the whole "extra power" from oval rings, then Q rings are still a poor design.

 

If you don't like the validity of the study then it is up to you to demonstrate why not.

 

[MTB Kid]

Is the jury still out on these? Apparently Mr Sastre used them in the Tour - seem to have worked for him?

[GoLefty!!]

Conclusions:

The Rotor System Crank shows very attractive performance indices compared to a circular chainring in the original crank orientation but we can still improve the performances of the RSC by re-orienting the crank arm to the ?optimal? crank angle versus the ?virtual major axis?: significantly more power output with lower peak load on the knee extensor muscles and keeping acceptable peak loads on the knee flexors and on the hip joint muscles.
The Rotor System Crank (?optimal?) performs much better than all the investigated non-circular chainrings in our study in terms of crank power efficiency versus circular. As to the peak joint power load indices, they are comparable with the indices of the best non-circulars (e.g. Osymetric-Harmonic) with crank in ?optimal? position.
An important difference between a non-circular chainring and the Rotor System Crank is a.o. that during one complete pedal revolution, for the RSC, there is only one deceleration phase and only one acceleration phase, whereas for a non-circular chainring there are two decelerations and two accelerations. This difference may lead most probably to a positive physiological impact compared to non-circular solutions.

Our biomechanical model confirms greatly the benefits of the RSC as shown in scientific studies carried out by prestigious international universities (see Rotor Website: a.o. Dr Cordova et al., University of Valladolid, Castilla-Leon, Spain). These results demonstrate that the Rotor System Crank achieves a real increase in power of + 16%. Other benefits are a.o. reduction of knee injuries.
Our study shows crank power indices from 111% to 117% (criterion 2) versus circular, depending on the crank orientation and also very favourable peak power load indices on the knee extensor and knee flexor muscles (criterion 1 and 2).

The Rotor System Crank is not only a brilliant example of inspired engineering, excellent design and high standard manufacturing workmanship, but the RSC is also, to the authors opinion, a biomechanical (-dynamical) cycling solution that works.

oh my it seems the author is claiming that the Rotor System Crank offers real biomechanical benefits, better than oval rings. But also that oval rings are better than circular rings.

 

nuff said, thats it no more debate needed. Q-rings work and they ar better than circular rings

[2 X 2]

Yes for Q Rings  They work for me.  We use them on the tandem and they work.  I think Q rings work better for people that peddal with power rather than spinning