Oval/elliptical chainrings

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2008-07-30 10:16 AM

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Pro
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Tejas
Subject: Oval/elliptical chainrings
 I was in a LBS yesterday and the owner offered up some chainrings that were oval. I can't remember the brand, but he mentioned someone using them in the Tour this year. Does anyone have experience with this type of chainring? Can anyone give me the name of this product? I was wanting to research them online, but I simply forgot the product name. They were not Shimano or one of the big name component manufacturers. Is this something I can use all the time for long rides or is it mostly a specialized component for time trials?  

2008-07-30 10:19 AM
in reply to: #1569749

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2008-07-30 10:45 AM
in reply to: #1569749

Elite
2527
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Armpit of Ontario
Subject: RE: Oval/elliptical chainrings

Carlos Sastre rode the TTs with Q Rings and I think he made out okay in the Tour 

 

I have the same 54/42 aero Q ring set up and although I'm not entirely convinced they have improved my pedalling efficiancy, increased my wattage by 3%, lowered my HR by 2% at the same wattage and increased my speed at same HR, decreased lactic acid concentrations by 9% or reduced stress to my knees (all things the manufacturer claims based on numerous independant studies) I have no real reason to go back to round rings.

http://www.rotorcranksusa.com/science.shtml



Edited by sty 2008-07-30 10:57 AM
2008-07-30 11:22 AM
in reply to: #1569749

Elite
2527
200050025
Armpit of Ontario
Subject: RE: Oval/elliptical chainrings

My bad - Sastre actually rode Q rings for the entire Tour, using 54/42 for TT and 53/38 road config.

They did some brand-cloaking by rebadging the rings as FSA  http://tour-de-france.velonews.com/article/80811/how-carlos-sastre-s-cervelo-p3c-is-tuned-to-help-him-win

 

 



Edited by sty 2008-07-30 11:52 AM
2008-07-30 12:55 PM
in reply to: #1569749

Pro
6838
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Tejas
Subject: RE: Oval/elliptical chainrings
 That's the one. I wasn't looking to buy speed, but merely looking to replace my chain rings that are looking pretty ragged. He did not have a replacement in stock and pulled the q rings off the shelf. At almost triple the replacement cost of my Ultegras, I was just curious if anyone here was riding them and found the added cost worth it.
2008-07-30 1:25 PM
in reply to: #1570306

Elite
2527
200050025
Armpit of Ontario
Subject: RE: Oval/elliptical chainrings

Not sure what retail price is, but it's not hard to find them discounted.

I bought them a few months ago from FACT Canada, where a set of 53/40 130BCD rings is around $130 with free 2-day shipping.

 

 

 



Edited by sty 2008-07-30 1:27 PM

2008-07-30 1:28 PM
in reply to: #1569749

Pro
3705
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Vestavia Hills
Subject: RE: Oval/elliptical chainrings
Explain, if you would please, the concept behind why one would want a non-round chain ring?  I do not doubt that there is a valid one, it is just that I cannot get my tiny brain to think of it ...
2008-07-30 1:55 PM
in reply to: #1570446

Elite
2527
200050025
Armpit of Ontario
Subject: RE: Oval/elliptical chainrings

brian - 2008-07-30 2:28 PM Explain, if you would please, the concept behind why one would want a non-round chain ring?  I do not doubt that there is a valid one, it is just that I cannot get my tiny brain to think of it ...

It reduces the effects of the "dead spot" in the crank revolution, providing a smoother pedal action and providing a more fluid force throughout the entire pedal revolution. 

Rotor Q-Rings help to minimize the time spent in the dead spot while pedaling. While oval chainrings have historically been controversial, we believe that allowing a rider to fine tune the chainring position offers opportunities to minimize the dead spot never before realized with conventional chainrings.

How do Q-Rings work?

Q-Rings reduce dead-spot negative effects due to its effective variable gear oval concept. The effective gear is lower at the dead-spot zone, so it is easier, faster and more comfortable (smoother) to pass through it. Once the pedal is over the dead-spot and enters the down stroke, the Q-Rings progressively increase the effective tooth size as more muscle strength is available.

A 53T Q-Ring at the dead-spots is equivalent to a 51T, so it is easier to move through the dead-spot. But as the pedal goes down and more strength is available you can see how the gear (effective tooth size) gets bigger: reaching the equivalent chainring tooth size of 56T during the power phase. ( http://www.rotorcranksusa.com/i1-q-rings.shtml  )

And an abridged report of a study that is actually understandable: http://www.rotorcranksusa.com/pdf/qringssummary.pdf

 

 

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