miércoles, junio 17, 2015

O-symetric versus rotor Q rings

O.symetric ya en España
Breve historia

Bienvenidos a O.symetric España, distribuidor del sistema de platos no circulares O.symetric. En virtud del acuerdo de licencia con la compañía francesa BioSquat/O.symetric y Jean Lois Talo, el inventor, la distribución para España será a través de la empresa Meam si Torn.S.L. (www.meamsitorn.com).
Los platos no circulares han estado en la mente de todo el que ha buscado la mejora del rendimiento ciclista. Los primeros prototipos de platos no circulares surgieron en 1913 del ingeniero E. Rocca y posteriormente E.Lantier (1928), Carl Enjer Larsen (1946), E.Polchlopek (1970), Prof. Okajima: Shimano Biopace (1983), B.Rosset (1993), M.L. Hull (1991). La revolución surgió en 1993 de la mano de J.L.Talo y M.Sassi en Francia, con el diseño O.symetric-Harmonic, aunque no fue comercializado hasta 2004, bajo la marca O.symetric, con algunos éxitos importantes en el ciclismo profesional de la mano de Bobby Julich.
Entre los muchos profesionales que han usado O.symetric en competición, obteniendo resultados a nivel internacional con Bobby Julich, Alexander Vinokourov y David Millar. Más recientemente destacar a los componentes del equipo Sky: Geraint Thomas, Christopher Froome y Bradley Wiggins, estos dos últimos 2º y 3º en la Vuelta a España y Bradley sub-Campeón del Mundo de contra-reloj individual.

Mejora con O.symetric
La revolución del rendimiento ciclista.

Desde que se inventó la bicicleta, los ingenieros han estado dando vueltas a un problema: ¿Cuál es la mejor manera de transferir el movimiento arriba y abajo de la pierna del ciclista en energía potencia eficiente a la rueda trasera?
Con los platos tradicionales redondos inevitablemente tenemos dos puntos muertos en cada ciclo de pedaleo, dónde mecánicamente la pierna no puede realizar la fuerza necesaria para pasarlos sin dificultad; a los ingenieros no les gusta esto porque es ineficiente.
Recientes estudios de investigación (“Comparative biomecanical study of circular and non-circular chainrings for endurance cyclists at constant speed” M.Malfait, M.Mech Eng et al. 2010) concluyen que el mejor sistema de transmisión no circular es el diseño de O.symetric.
Otras publicaciones dónde fisiólogos comparan el rendimiento de ciclistas tanto con platos convencionales como con O.symetric concluyen que:
La potencia media aplicada para una misma zona de intensidad, correspondiente al 80% VO₂Max, se observa un incemento entre un 6% y un 18% de la potencia aplicada.
La velocidad media se incrementa en un 3,5% usando O.symetric
La frecuencia cardiaca disminuye un 2% de media en todas las zonas de intensidad usando O.symetric.
10% menos en producción de lactato.
2% de mejora en el rendimiento respiratorio a intensidades máximas.
10% más de potencia pico, por ejemplo en un sprint.
Más facilidad para mantener una cadencia de pedaleo elevada, tanto en llano como en subida.
En la segunda transición de tiatlón,de ciclismo a carrera a pié, los deportistas que usan O.symetric disminuyen el tiempo de adaptación para ser eficientes en carrera a menos de la mitad.



January 29, 2014 · by ernestkhong · in All, bike, Gear, review · 2 Comments
Before I begin I would like to make it clear that Osymetric chainrings are different from Rotor’s Q-rings or their new QXL-rings for that matter. One is Spanish and the other French. Rotor makes complete cranksets whereas Osymetric makes chainrings and pretty much nothing else.

Now you might say both chainrings are not round. That I would agree. Well, maybe more specifically, they are not circular. That is pretty much where the physical similarity ends. Osymetric chainrings are not elliptical as many presume them to be. Both Rotor and Osymetric set out with the same agenda – to eliminate dead spots in pedalling circular chainrings. That is because our legs are just biomechanically incapable of turning perfect circles. Both attempt to accelerate your feet through top dead centre (TDC) and bottom dead centre (BDC) by having a lower effective tooth count. For the 52T pictured below it is effectively a 56 at the power phase and a 48 at the dead spots.

Rotor Q rings have the same basis for their design. But the degree of ‘ovalization’ is much lesser. To be precise, Osymetric rings are not ovalized. Instead they are a ‘twin-cam’ design – two circular rings offset from each other and then joined by flat spots where your TDC and BDC are. Jean-Louis Talo, father of Osymetric, says that at the dead spots our legs have no strength. Hence the radius of the chainring needs to be drastically reduced to help us through that area. If we were to plot a curve illustrating the power generated at the power stroke vs the dead spot, the spike or dip in power would be rather drastic, not a gentle oval as the manufacturers of the Q-rings would like you to think it is. Even then, they have recently launched the QXL rings which have a more pronounced ovalization, it still does not come close to the benefit of having a flat spot to cancel out the dead spots in our pedal strokes.

That is not to say that Q-rings offer no benefit. James Cunnama, a professional triathlete, won 2 70.3 races on Q-rings after his standard rings got stuck in custom. He is now a Q-ring convert. But perhaps he was already stronger to start with? As we all know team Garmin-Sharp is sponsored by Rotor, but not all their riders opt for Q-rings. On the other hand, several pro tour riders have gone against the wishes of their sponsors and put blacked out Osymetric rings on their bikes. Sir Bradley Wiggins, Christopher Froome and David Millar are just a few of these riders. Frederick Van Lierde, last year’s Ironman World Champion is another long time Osymetric user. I personally have not ridden Q-rings. But my coach Shem rode them for a while before switching to Osymetric. The advice he gave me was to go the whole hog and give Q-rings a miss.

How does it ride?

Some of you may expect me to be bouncing up and down my seat, but I found the rings surprisingly natural. The adaptation I believe is one that is more psychological than physiological. The trick is to not think about the rings being weird and just pedal round circles like we normally would. Bear in mind that although the chainrings are not circular, your pedal stroke is. The chainrings do not alter the feel of your pedal stroke.

As you can see from the above picture they fit perfectly on the SRAM Red 22 crank. The new SRAM cranks use a new bolt arrangement. Fret not, it is still 5 bolt but they have moved one of the bolt attachments to just below the crankarm. As such the installation instructions that come with your Osymetric chainrings will not make sense. Just install the chainrings as pictured above, which is pretty much the opposite of the instructions, ie. the “52” and “130” goes opposite of the crankarm.

Why isn’t everyone using them?

If non-circular rings are that great, why aren’t all cyclists putting them on their bikes like Zipps? While innovation is mostly welcome, we are very reluctant to change. It does not help at all the Osymetric suffers from shifting issues. Shifting is best done only in the power phase else the front derailleur has little to push against. Earlier versions of the Osymetric chainrings lack shifting pins and ramps which exacerbate the shifting issues. Installation can be a pain too. Osymetric offers a video which makes the installation look like a breeze. If you opt for the 56T, it may not fit the upper limit of your derailleur braze. However with practice and a good mechanic, the loss in shifting performance can be minimized.

Cost is another issue, at over 300 bucks for a set, it is quite hard to justify forking out that kind of cash when you have to ditch your still working circular chainrings. And above all, it is just not cool. But then again, Adamo saddles were frowned upon not long ago.



Jean-Louis Talo - inventor of Osymetric

Osymetric – Gimmick or Legit?
At this year's Tour de France I met an interesting gentleman named Jean-Louis Talo. He was carrying a set of these wacky looking chainrings that I had seen around so I struck up a conversation. I had seen them being used on most of the Team SKY bikes as well as knowing that a few other pros were using them which started to pique my curiosity. As it turns out Jean-Louis is the inventor of Osymetric and he was happy to explain them to me.

The Dead Spot

Jean-Louis Talo is a biomechanical engineer who created the Osymetric chainrings 21 years ago. He understood the theory of “the dead spot” and wanted to improve the efficiency and dynamics of the pedaling cycle. What is this mythical dead spot? The theory states that it is the weakest part of your peal stroke where the crankarms are in the 12 and 6 o’clock positions . Imagine a piston at the very top and bottom of its cycle. There is significantly less power being generated at this transitional point. The shape of the Osymetric rings attempts to concentrate your pedaling power where your force is at a maximum, while effectively reducing the load where your power input is at a minimum. This decreased chainring radius helps you go faster through the dead spot. For example, for a 56T (Osymetric) at the top position (the dead spot) it is not a 56t, it is equivalent to a 52t (easier to think of it being the same diameter as 52t at this position). So, where you are at your weakest, the chainrings are at their smallest to help you go through that quicker. Where you are strong is where the maximum diameter of the chainring is. At the end you have a constant speed of rotation.

Why Are Chainrings Circular Anyway?

Why have chainrings been circular for all these years? According to Jean-Louis, until 1980 the industry was unable to manufacture another shape. Simple as that. It was not a biomechanical decision. As manufacturing techniques progressed and laser cutting became economical, precision shapes were possible to be produced. Jean-Louis’ recognised that the rider has to adapt himself to the circular chainring and he began to experiment with different shapes. Osymetric attempts to adapt its shape to the person.

What about Biopace?

This is the first question that everyone will ask Jean-Louis. As he explains, Biopace was the exact opposite as Osymetric. It was totally wrong from a biomechanical perspective. First of all because it was oval. According to Jean-Louis, a shape needs to be created that is fitted to the pedal stroke – and that shape is not oval. Secondly, Biopace set the crank in line with the large edges of the chainring. With Bio-Pace you actually lost power.

Claimed Benefits

Osymetric claims to produce less lactic acid at your threshold power. On circular chainrings you produce more lactic acid because your vastus externus is employed for too long and being pushed too hard throughout the pedal stroke. Therefore the smaller muscles are used more than your larger muscles could be. With the adapted pedal stroke that Osymetric provides, all the muscles work proportionally to their strength. More muscle fibers are recruited by using the Osymetric shape throughout the pedal stroke which means that each has to work less. This is the theory.

Osymetric claims that you will increase your power 10% with their chainrings. Note that the power is not the speed however. The net result is claimed to be 1% faster and is slightly more efficient when you are climbing than when on the flat. The difference is 0.9 km/hr when climbing, and 0.7km/hr when on the flat.

According to Jean-Louis, he did some testing with Bradley Wiggins during this year. With circular chainrings he tested 450watts at a 20mins average. With Osymetric chainrings Wiggins generated 490watts average (20mins ave). I have not independently verified this, but it’s a point that Jean-Louis is eager to talk about.

My experience

Jean-Louis sent me a set of Osymetric chainrings a couple weeks ago. They came in some ghetto packaging with Ikea-like instructions. Even though these chainrings were just used by the winner and dominating team (SKY) of the Tour de France, I had to remind myself that this is no mass operation. It’s basically a one-man show.The first week I spent countless hours trying to fit them to my Dura-Ace cranks and running back and forth to my bike shop (thank you Bikes@Brighton). Installation is not easy and there is no good manual out there that was able to help (Osymetric has this video, but they make it appear easy).

After speaking to the local distributor (Barry Wallett; cantravel_100 at hotmail.com) I was able to follow his advice and get the chainrings fitted. I was still unable to shift into the little chainring properly, so I adjusted the front derailleur so that it stayed on the big ring.

There’s no question that riding these chainrings for the first time feels weird. It’s the exact sensation you’d expect from the shape. However, after 30 minutes of pedaling they began to feel perfectly normal. In fact, far better than normal. I couldn’t believe how good I felt while turning over the pedals. I was doing an SE interval up the 1 in 20 (outside of Melbourne) and managed to pull off a time of just over 15mins without even “going for it”. This is far from being scientific, but it wasn’t normal.

The next day I raced our Club Championships with the Osymetric chainrings. It was my first road race in months so all I wanted to do was finish. I felt like I could win it (same old story…I missed the break)

I could be just imagining it but riding these chainrings has felt undeniably awesome. You know those days where you’re pushing a bigger gear than normal and every time you go through a pedal stroke you think, “I can’t believe I’m pushing this”? I have this feeling only a couple times a year when I’ve trained my guts out and been on top form. I have nothing to gain by saying this: I feel like a completely new rider using these chainrings.

What the pros say

It seemed strange to me that if the reported benefits are so great why aren’t all the pros on them. Nobody is sponsored by Osymetric and nobody officially endorses them. In today’s world of multi-million dollar sponsorships, Osymetric stands alone on top of the podium with many victories – including the Tour de France.

I skyped with Richie Porte last night to ask him about what he thinks. Although Richie is able to hold back his enthusiasm towards Osymetric better than I can, he says that he’s definitely a fan. For comparison purposes, he rode Puig Major (a popular climb in Mallorca) on Osymetric rings at an average of 422 watts with a time of 23:59. It was 25watts more than he did this climb previously with normal chainrings. Again, not scientific, but something to consider.

The first professional user of Osymetric was Bobby Julich. Bobby got onto Osymetric by a series of chance events later in his career and won silver in the 2004 Olympic TT (he originally won bronze but Tyler Hamilton was stripped of his gold medal) and many other races in 2005 including Paris-Nice. Of course you don’t just get these chainrings and start winning races, but it’s a great outcome. Bradley Wiggins later got onto Osymetric in 2009 and subsequently finished 4th in the Tour de France. Shortly after Jean-Louis had a good contact within SKY. Now look at the growing list of riders:

Brad Wiggins
David Millar
Richie Porte
Jani Brajkovic
Chris Froome
Chris Sutton
Geraint Thomas
Greg Henderson
Lars Petter Nordhaug (just won Grand Prix Cycliste de Montréal)

I gave Bobby Julich a call last night to get his thoughts and he was extremely generous with his time. He spoke to me for an hour telling me about his past experiences with the Osymetric chainrings. When I asked him what convinced him that these work, he replied, “I was never interested in quantifying with numbers if they did or didn’t work. I heard all the numbers that sounded convincing but at first I just wanted to try them. When I put them on and it was llike ice skating – it felt awkward. After half an hour though I thought that they felt so good and natural. Right then I was sold. It had nothing to do with the numbers.”

I also got in touch with Greg Henderson how has used Osymetric for a couple years now. He tells me that he definitely feels like he gets more power out of them, but they’re not as effective for explosive power in the sprints. That said, Hendo has won some pretty big sprints on these chainrings. This is consistent with what I’ve heard from others. The high-end kick seems to be missing.

What the research says

I had wanted to do some of my own testing to try to quantify the savings but after some thought this would take some Vo2 Max equipment, very accurate power meter calibration, lactate samples, and other resources. It’s not as simple as sitting on a stationary trainer and measuring speed at a certain wattage.

It’s difficult to find conclusive research but there are some studies which use mathematical modeling on a variety of elliptical chainrings worth looking at:

This study makes some reassuring statements about Osymetric, but it does also state that the orientation of the chainring on the cranks is slightly off (p.25). It also talks about how the rider’s position and geometry of the frame affects the orientation of various chainrings. However, Jean-Louis strongly denies this by saying, “This study was only a mathematical solution. They are not testing this in a physical lab – it is a mathematical model. I love mathematics but this also has to be tested in the physical world. Imagine, where is the dead spot is. It can only be in one place – When your legs are straight up and straight down – just like a piston in an engine. If you move forward or backwards on the saddle, or the geometry of the frame changes, it makes absolutely no difference to the variation of the Osymetric curve.”

Osymetric also have some studies on their website which obviously report significant benefits: http://www.osymetric.com/images/stories/etude.pdf

I’ve heard that some sports scientists say that the shape of the chainrings fools the power meter readings into make the measurements appear higher than they really are. Update: I asked an SRM engineer about the possibility of this and he tells me that it would be impossible for the osymetric chainrings to affect the readings of an SRM powermeter.

Rotor Q-Rings

I have no experience with the Q-rings and haven’t spoken with anyone from the company about them, but do know a few people who highly rate them. Garmin-Sharp have a sponsorship arrangement with them, however if you look closely you’ll notice that many of the Garmin riders will use the Rotor cranks with circular chainrings, not the oval ones.

The interesting thing about the Rotor crankset is it allows you to position the Q-rings however you want. I asked Jean-Louis about this and he told me that Osymetric is very different from Q-Rings. Jean-Louis believes that in order to eliminate the dead spot you need to create a shape that is biomechanically fitting. He claims that the oval shape does not fit to the legs.

As Jean Louis explains, “Imagine that one of your legs is in the dead spot position. Your strength is divided by 2. You have no strength in this dead spot area. For this reason you have to drastically decrease the radius as part of your chainring to help you go through that dead spot easily and quickly. When your crank is in the strongest position your strength of your legs has been multiplied by 2. For this reason you need a great variation in the radius. If the variation is small you have absolutely no effect”.

“The curve between the high dead spot and the low dead spot is not oval. It’s a creation in function of fitting to the static strength and dynamic strength. For this reason the shape of Osymetric is so particular. Between these two dead spots the radius varies proportionally to your strength. Its fit for each muscle of your legs. In studies, much more fibers in the muscles are working, but each fiber works less. This increases the rider’s lactic threshold is increased. This is important because competition is always decided at lactic threshold. “

You can read more about Rotor’s Q-Rings here: http://www.rotorbikeusa.com/science.html

I don’t have a contact within Rotor so if anybody from the company is reading this feel free to get in touch to better explain the science and benefits.


The Osymetric chainrings are very basic when you look at them. They don’t have the chain catching mechanisms on the inside that enables quick, smooth and reliable shifting like Shimano, Campy or SRAM. They’re basically a thin piece of alloy which have been laser cut in its unique shape.

A look at the inside of the Osymetric chainrings on a Team SKY bike at the Tour de France

As I said before the Osymetric chainrings are very fiddly to install. There are a lot of derailleur and crank arm variations out there and the instructions included with the chainrings are very poor. However, after you understand how to configure the rings to your own bike it becomes much easier. The initial process was painstaking however.

Front shifting is far from being perfect on even the best of set-ups, but dropping the chain is a bit of worry with Osymetric. Careful consideration to which size differences between small and large chainring needs to be addressed. Bobby Julich explained, “The 52T or 42T/54T is a really good combination for flatter races and the 44T/56T is the bomb for time trialing. It’s the magic ring. But you have to be careful when using say a 42T/56T because the difference is so extreme and shifting might not be good”. Also, a brief pause in power while shifting needs to happen. Riders tell me that you’ll sometimes get flicked if you don’t think about your front changes. Time trial bikes seem to be more of a problem than road bikes when shifting. Bradley Wiggins has dropped the chain a fair few times in time trials (e.g. 2012 Tour of Romandie). However, he did use Osymetric throughout every stage of the tour which speaks volumes.

Pros who have experience with Osymetric have found the optimal place to shift. One pro told me, “You don’t want to shift when you’re in the dead spot. That’s when the derailleur has nothing to push against. It’s best to shift when you’re on the power stroke so the derailleur has something to push the chain against. I always had to shift in the beginning of the power phase of the stroke with my right foot (because I’m right footed) and slightly let-off the power. As long as you shift at that right time, it’ll work perfectly”.


Jean-Louis says that it’s effective to go back to training on regular circular chainrings a week before competition and then put the Osymetric back on the day before competition. He calls this the “turbo boost”. I’ve asked around about this and this is what Bradley Wiggins does. However, most of the pros don’t do this because of practical reasons and not wanting to fiddle with the front shifting (most pros only have one training bike, but Wiggo would be well looked after).


People spend thousands of dollars on diminishing gains trying to improve aerodynamics and shed a few grams from their wheels and frames. Meanwhile there appears to be low hanging fruit right in front of us with optimising the dead spot in the pedal stroke. Many will pass this off as some cheap marketing gimmick, but after feeling them for myself I’m completely sold. I imagine if Osymetric had a marketing budget to shape people’s perceptions as much as they’ve shaped their chainrings, we’d all be sold. For the time being, they’ll just have to keep winning the Tour de France.


Q-Rings do have a few benefits compared to OS. First, you can adjust the position of the max diameter to match your position and desire (and you can adjust both the inner and outer). Second, Q-rings do have a smaller difference between largest and smallest diameter, making them less extreme and a bit easier to set up. Technically, OS are not even rings, they are two cams

Unlike one of the other respondents, I can easily switch between the 'Q'-rings and round rings. It seems to take only a few minutes to adapt. Not so the O-Symetric rings. I have stopped using them for now, but may make a more 'concerted' effort over the winter. I would not recommend just trying them in the middle of the season. You could do that with the 'Q'-rings, if you wanted to.


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