If osymetrics work, they would work far, far better for way more athletes if they had angular adjustment capability. A fixed ring forces you to take a gamble that the design will work ok with your set up. Kind of an iffy gamble.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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You are basing this on the assumption that the angle is critical. That may not be the case. It's quite possible that "getting close" is good enough, and that the rider can easily adapt to it.

Or it is possible that none of them really do anything to increase power...

If you actually read the noncircularchainring.be study on different shapes and angles you will find that based on their models there are a wide variety of angles that work quite well (interestingly enough the recommended by Rotor seems to be terrible). Yes this is for one position but, shifting your seat angle likely won't move outside of the range of angles which improve pedaling power. Below is a summary of information (all percents are in comparison to circular ring with Osymmetric ring):

• at 110 degrees to major axis: -7.9% peak force from the knee extensor, +15% from Hip Extensor and a +2.4% power increase {they consider optimal range based on power increase and knee force decrease}
• 117 degrees: -7.5%, +16.2%, +2.5% {they consider optimal range based on power increase and knee force decrease}
• 78 degrees (similar to standard mount for qring and osymmetric) : -1.5%,+4.6%, -0.7%
• 125 degrees: -6.5%, +15.4%, +2.9%,
• 128 degrees: -4.9%, +14%, +2.9%
• 132 degrees: -3.2%, +18%, +2.7%

As you can see there are at least 20 degrees in which you get a measurable improvement, the study didn't include any other data points in the document which I find interesting, but the point here is that you can at least get in this range of improvement on the rings, likely regardless of your seat angle.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

No, I wouldn't say the angle is "critical", but in my personal experience it is very important if you want to really find that sweet spot where these chainrings really shine.

And that non-round chainrings' optimal positions are affected by way more things than just seat angle. For example, the best ring position is highly affected by seemingly random things like BB height, chainstay length, gearing choices, cog size, etc.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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Thats an interesting study, but I'm not sure how much I trust it. It has the old Biopace chainrings being better than any of the current chainrings in their stock configuration. They only test the rings with a mathematical model though, and I wonder how much that actually reflects real usage.

My understanding of Biopace rings is that they did have some small improvements till your knee blew up.It would be interesting to see the point at which they modeled no improvement and decreasing improvement for shape.

As for application to the real world: I know approximately nothing about bio-mechanics and feel unqualified to make any judgement on this. I know that the guys who put together the model know more about this then I do and have yet to hear anyone else who actually knows about this stuff either point out its flaws or endorse it. There for I trust it with some reservations.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

I guess you guys haven't heard about our QXL Rings :-)

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Kervin

Rotor Bike Components USA
OUR NEW WEBSITE http://www.rotorbikeusa.com

I've found that a LeMond Revolution trainer has enough inertia to observe the "non-round ring on an SRM/Quarq inflation factor" ;-)

The "inflation factor" is also readily apparent riding outside with a PT wheel to compare it to...

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http://bikeblather.blogspot.com/

I've looked at those studies a bunch and it's not clear to me that the joint torques calculated by that model are correct since it appears that the model only considers a single leg...i.e. it doesn't take into account the fact that pedaling is done with a system of 2 legs coupled by the cranks.

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http://bikeblather.blogspot.com/

You would know better than me! I think it is still be worth testing, at least once though.


Unfortunately I have no access to either of these. Sounds like I have no accurate means of testing. So instead I'll have to rely on my gut combined with less than ideal testing. If you have any ideas for semi-accurate methods, given the following long list of things I don't have access to that would be great: velodrome, hills longer than 3 minutes to climb (which really sucks since I excel at climbing), powertap (or power meter for that matter), lemond revolution. I do have a trainer, rollers with a resistance unit, and might be able to get access to a computrainer. Might have been easier to list things I do have access to haha.

I know you had done testing with osymetric rings to show the inflation factor, have you done any testing to see if they actually work as advertised beyond that?

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

kervinq wrote:

I guess you guys haven't heard about our QXL Rings :-)

Kervin, I have heard about them. Last I checked they weren't available yet (or officially announced), but they certainly solve the aforementioned small eccentricity. But have a few issues with buying them: a) both rotor and osymetric rings are simply out of my price range b)I think an asymmetric shape intuitively makes sense if there are actual gains to be had by changing shapes of he rings, simply put the forces when entering the dead spot or much different than those when exiting. It could turn out that this doesn't make many or any gains but I simply don't know, much like I don't really know if the concept at all works. So I simply follow my gut feeling and own (quite possibly flawed) logic, as well as the entirely unscientific experiences of others.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

http://forum.slowtwitch.com/...rch_string=;#4274299

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http://bikeblather.blogspot.com/

Interesting...especially since the O'Hara study that's shown prominently on the Rotor site was done using a Computrainer, no? Those don't have a very big flywheel IIRC...in fact, don't you remember ST'er "jens" having a custom 16 lb. flywheel machined for his Computrainer? ;-)

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http://bikeblather.blogspot.com/

DarkSpeedWorks. Yes Indeed... rings would be much better served with multiple mounting positions.

Something you made?

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Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook

Yeah been tinkering with some stuff for a while. This version was hot out the CNC yesterday, first test ride today, sifting to the roadie tomorrow for a few power tests. Shifting is a little twitchie.....:)

Let us know how it goes...

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Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook

Awesome work there, be intersted to see what you find. One of the things that is rather nice about these rings is they have very well shaped ramps and pins. Like I said before shift quality is better than it was with the Rival rings (which are crazy flexy). See picture below.


Took them out for their first longer ride today, felt wierd at first but by the end of 3 hours I didn't notice the difference at all. I did notice slightly different muscular use on the ride: more hamstrings, more glutes, seemed to work the quads the same (based on my fatigue level at then end of the ride). As for whether or not they work? Still no method to test that but I do know I'm certainly getting maximum placebo effect: I did the same route as I did last week at 1mph faster today, with less fatigue afterwords and winds were stronger today. But once again this proves nothing, so I'm going completely non-scientifically just believe they work and keep riding them.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

Are your rings Farther, Faster, More Interesting? http://www.youtube.com/...ed&v=fXHa6pcYwPg

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

Did you CNC the entire ring, or did you just add the extra holes to an off-the-shelf oval ring? Either way, that's some impressive work.

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Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
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Ding, ding, ding...

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http://bikeblather.blogspot.com/

The great thing here is that as long as they don't actually hurt my power output, and I believe that they work then they will work to some extent. I've also heard many argue that they have no power benefits but fatigue benifits once again.... no data. I choose to believe and therefore they work. Placebo effects are fantastic.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access

If placebo didn't work, they wouldn't have to control for it in studies, right? :-)

It's funny...the guy who I'm borrowing the Osymetric ring from told me straight out that he doesn't care if it inflates the power on his Quarq and/or if it actually helps his power...he's sticking with them just because he likes how they feel.

Whatever floats your boat, I guess... ;-)

Depending on how things work with my experiment with them on the TT rig, I may end up using them there for the same reason. However, that then brings in the difficulty of having the inflated power values...unless I go back to running my PT wheel with a cover again. But, I'm also going to compare the effects the Osy ring in the "optimum" position vs. shorter cranks on a "feel" basis. My suspicion is that the "feel" will be similar.

Whatever floats your boat though, I guess... ;-)

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http://bikeblather.blogspot.com/

When you say "Optimal" do you mean rotated 4 clockwise? This will get you close to the theoretical optimal for a road bike setup, but 10-12 degrees off for a tri bike angle. Trying a run with the mod setup I have to dial it in a little closer tonight. Will update if people are interested. Not sure I"ll have time to fit the large flywheel on the test set-up, but I'll run a round and osymetric original position along with the modified position. Might start a new thread since this is outside the DOVAL spectrum.

I think of it as "rotated 180 degrees and then back 36 degrees to line up with the arm" ...I'm not sure if that's the same as "rotated 4 clockwise" or not ;-)

IIRC, The major axis of the Osymetric ring was at 78 degrees from the pedal in the "stock" position. Effectively "retarding" that position by 36 degrees puts it at 114 degrees off of the crank arm, or only 3 degrees off of their calculated optimum for the major axis. Judging by the fact that there was only a difference of 0.1% between their predicted "power gain" at 110 degrees vs. 117 degrees, I'm thinking 114 isn't going to be somewhere in between. I also recall them saying that anything in the range of 110-120 degrees was in the "sweet spot" for positioning, no?

Hmmm..."10-20 degrees off for a tri bike angle"? Well, based on the above, plus the fact that I don't think I sit effectively 10-20 degrees different than my road position, I'm not sure how you're arriving at that conclusion.

BTW, my perception using that ring position on the road bike is that it would feel better if I was sitting further forward (i.e. really deep in the drops, or in my TT position). The pedal "drops away" really fast when using it and riding on the tops of a road bar...

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http://bikeblather.blogspot.com/