@Bioteknik What’s your analysis of this study regarding oval rings Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test - PMC
Higher maximal force which is statistically significant.
Table 1 shows no significant increase in flywheel velocity though.
I’ve just skimmed the article. Will read later in more detail, but initial thoughts suggest too many holes in that study to draw any meaningful conclusions. Raises to many questions…
Sample of 20, and all from a similar background. We can’t say that this is generalisable to cyclists as a whole.
Only looks at sprints from a standing start of 8 sec whilst seated. That’s not how the majority of sprints are done. Again, can’t say that this is generalisable to cyclists at the end of an event.
In relation to the above, what do we know about how that seemingly small increase in power will translate into fatigue at the end of an event.
I could go on…
I’ll read in more detail as I’m interested in this at the moment. Spent the winter on Q-rings that I tweaked the position compared with last year. I’ve noticed a few interesting things going to round rings on the race bike that’s made me seriously consider switching to Q-rings all round.
Power inflation (crank based PM’s with elliptical rings)…I can’t tell from the “Data Collection” section if they compensated for this or not as I’m not familiar with the equipment. If they didn’t the results are flawed I believe.
All I’ve read over the years is the mechanical advantage of the down stroke and the up stroke basically equals a round ring…
In the decade or so I’ve used them on the road and TT bike (both with Quark PM’s) I’ve returned to round rings on the road bike as I feel the peak power is better with round rings. I left the Q rings on the TT bike. When they wear out I plan to go back to round. They have always felt good but, going back and forth was never a noticeable thing after a few pedal strokes.
I can’t recommend them over any other ring.
Tom A from Slowtwitch posted this article years ago about how the ankle negates the elliptical rings mechanical advantage (the knee and hip don’t see the effects…). Fascinating stuff if you’re a bike nerd.
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That’s an interesting article. The argument of no metabolic rate change = no effociency gain is an interesting comment.
Seems impossible to study effect on knee force or other manufacturer claims.
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I had a crazy thought while reading this thread, if ya’ll’ll (how’s that for a contraction?) kindly indulge me:
Is it possible to mount an elliptical ring in exactly the wrong orientation? (Never owned or ridden a nonround ring, so I dunno.) That is, can the ring physically be mounted such that the lobe is exactly in the wrong spot, like 90° away from where it’s supposed to be?
The reasoning here is that if, as @KorbenDallas’s linked article suggests, the ankles compensate for ellipticality, then the “wrong” position shouldn’t feel worse or suck your watts. And if the “wrong” orientation does have an effect, the nature of that effect should provide insights into whether and how the “right” orientation works.
Just ask the Shimano Biopace design team…
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This is what i noticed as well. Measured power was higher, but it didn’t produce a higher speed.
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The strain gauge was mounted on the friction belt that surrounded the flywheel for measurement of the instantaneous friction force applied to the belt.
Shouldn’t be any inflation from crank based measurements.
I was wondering when somebody was going to mention Biopace chainrings. I remember when those came out - late 80s/early 90s, then 6 months later everybody had patellar tendinitis and they disappeared from the market. Are the new ones different somehow?
Yes. Biopace had max tooth size at the dead spot. Rotor-Q rings have minimum tooth size in dead spot
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And some took the BP rings, and indexed them differently to alter the effects.
Aha. That answers my question.
But if putting the ellipse in the “wrong” position generally leads to bad results, why does the “right” position lead to merely mixed results? (Haven’t watched the vid you linked yet.)
I’ve been debating trying nonround, but haven’t wanted to spend the money if the results are as iffy as it seems.
I can’t really say. I have only done limited review of non-round stuff, and at best it seems very marginal and debatable. Some people love them and others not. I have only spent a very limited time on them and think off-road is a place I would like them the most.
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Rotor has a 30 day money back guarantee on their rings.
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Two wrongs don’t make a right. Playing backwards a recording of someone speaking lousy English makes it unintelligible, but playing it forward it’s still lousy English.
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My dad had biopace rings (on 165 cranks no less) back when biopace came out. That bike was a beater bike that us kids could use when we came to visit. I tried them on a fast group ride with a super young Larry Warbasse and an old ski friend turned pro for Saturn Chris Fisher. I kept up just fine and after a short while everything just felt normal.
Fast forward to Rotor Q’s…I was given a set and tried them. They felt good so I kept them on.
Fast forward to today. As I stated above I think I generate more power sprinting with round rings so that’s what I ride now.
Reading people talking about how good or bad or different the types of rings are without trying them is funny to me. Overall, I’m left with the fact that you still have to push 53 teeth 360 degrees and given they have found (study linked above) that the ankle nullifies non round ring affects, just ride with a ring and don’t worry about finding any gain here. If someone gives you a set go for it otherwise I’d save your money.
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Good to know. Thanx. 
I was thinking that myself: maybe round = good; nonround “right” = no big diff/not wrong enough to notice; nonround “wrong” = bad.
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