Ovale Tandwielen : Osymetric's -Q&A Pag8-

[Ruben S.]

rotor rotor rotor

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maak het jullie niet moeilijker en investeer in Osymetric

Waar doe je die investering?

in de bladen natuurlijk

((lees de vorige bladzijdes voor antwoorden op u vragen))

Maar welke (internet)shop verkoopt ze voor hoeveel.
Dat vind ik op de vorige pagina's niet

[BelAir_500]

http://www.osymetric.com/

[madskatingcow]

Ondertussen wat research gedaan en op volgende site terechtgekomen : http://www.noncircularchainring.be/

Hier is een wetenschappelijke studie gepubliceerd met onderzoek naar alle ovale tandwielen (O.Symetric, Rotor, Biopace, Rasmussen Oval, etc) : Biomechanical study chainrings.pdf

Conclusie :

Assuming the optimal crank orientation, the ‘academic’ Rasmussen Oval and the O.symetric-Harmonic may be considered as being the best performing non-circular chainrings. The Rasmussen Oval however shows some milder figures for the knee extensors whereas the O.symetric is milder for the knee flexors and the hip joint muscles. Both these noncirculars reach the best power efficiency index compared to the other noncirculars.
For the O.symetric, deviating from the optimal crank position does not lead to important changes in the peak power indices of the knee extensor muscles. Most probably this has to do with the specific shape of this oval.
Consequently, O.symetric has a more extended optimal crank position area.


The Q-Ring is a brilliant example of excellent manufacturing workmanship but is first and foremost a compromise solution due to technical compatibilities and marketing reasons: ovality 1.10, slightly modified ellipse and crank at 74°. But as with all compromises, this oval is sacrificing most of its potential advantages. The problem of the Q-Ring is firstly its lack of ovality and secondly, the crank orientation. Even with the crank oriented in the optimal position the Q-Ring performances are disappointing and remain very weak.

[madskatingcow]

Respons van Rotor :

Hi,

I wouldn’t want to undermine the expertise of the Belgian team who carried out this study, but there are many things that our Independent scientific studies and research with a number of far more experienced biomechanical doctors than this team, made clear to us:

1) Primarily: The effectiveness of a chainring on a trainer is not a good indicator of its effectiveness in the real world (due to inertial and practicality considerations). This study was carried out on trainers.

2) As much as a extreme ovalization may give a benefit in POWER, it is impossible to use daily, maintaining a smooth spin and protecting the knee's health

3) EFFICIENCY is more important than power. If you could choose a modification to your car that would give you 16% more power, more engine wear and no efficiency gain, or one that would give you 10% more mileage, less engine wear and 4% more power.... which would you choose... considering that the engine is you. As much as power is the favourite word in cycling, averages is more important. If we offer you a product that allows you to keep your average speed up, reducing your average lactate concentration and improving your endurance, we will give you a product that always works to help you. However if we only give you a product that claims 16% more power in sprints and no further benefits... do you really sprint all the time?

4) We had many of the same assumptions on Orientation and ovalization as the doctors of this study when we started the Q-Ring project. However, feedback from professional athletes, and studies of their real world results, showed us that our (and the doctors) assumptions were flawed, and we decided to design a product that wasn’t "theoretically" perfect - rather, a product that actually works and does what the professional athlete needs.
The proof of which system works, is visible in who chooses to use it and its results. As an example: no other oval chainring has won the modern tour de France, and no other oval chainring has ever been used on every single stage of the race. We designed the Q-Ring to always work, to be easy to use and to give real world benefits. You see, theory doesn’t achieve results in the real
world. It is a good place to start, but in the end results, results and results, are what shows whether a product works.

The Specialized version of the Q-Ring is only available in Red inner and red outer. Some of the photos show team versions or prototypes. We don't sell direct from the factory, but prefer to support our network of distributors and dealers.

The distributor for Rotor products in your Area is Combee:

Contact them here:

Combee Kunstoffen
Transporstraat 42
4283 Giessen JL
Netherlands
combeekunstoffen@planet.nl

+31 183441417

They should be able to help you find a local dealer. Please do not hesitate to contact me for further information.

Rotor Bike Components

[radical]

Voor die prijs kunnen ze voor mijn part alle kromme bladen in hun aars schuiven, maar op dit niveau van gerief PUSHEN hadden ze bij mij zelfs aan 50 euro per set geen kans gemaakt.

Ik hoop dat mtb.be een advertentiepercent krijgt van die ohsosissen.

[madskatingcow]

op dit niveau van gerief PUSHEN hadden ze bij mij zelfs aan 50 euro per set geen kans gemaakt.

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[coureke]

wat is het best bij cyclocross ovale tandwielen of ronde