Oval Chainrings.. Thoughts?

Thanks. That’s better than 100% most of the time and then the occasional
drop chain or no shift etc as that could happen at the wrong moment (in
a race).

Thanks again.

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My first thought …

While back in the US visiting family, I was given a small steel-framed Trek from 1987. Good quality. Trek really made them well, Reynolds 531, good Shimano parts and a triple (SR) up front.

I studied it a little closer when I took it apart to renovate and give it TLC. The front big ring was oval. That was evidently standard on Trek models with a triple back in 1987.

I won’t tell my wife (it is small enough for her) and see if she makes any remarks about shifting etc.

Oh.
Is that a Shimano Biopace chainring?

I remember mid to late 80’s the Biopace chainrings came out. They were vogue for about a year, then I think had law suits for causing knee problems. Anybody know the difference between these and the current crop of oval rings?

They are “clocked” differently and aimed at handing power differently.

One video that is from a biased source, but covers the essential difference:

I need to find the article, but some people have chosen to use the Biopace rings and simple reinstall them rotated different from the original intention. I don’t remember if it is forward or backward rotation, and if it’s one or two crank spider holes, but it gets to something more like the “modern oval” rings when you do that.

This might be one place I’ve seen it:

And this article is possible useful (I just skimmed it so far):
http://oval-chainrings.com/oval-chainrings-are-not-new-at-all-shimano-biopace/

And why not add an article from the master (RIP):

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Biopaced was clocked 100% backwards.

I couldn’t get a 105 front derailer to work at all with absolute black 2x rings.

But I am 100% all for them on a 1x setup.

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the ones from absolute black, made my sprint at 1100wats 1mph faster

and they are the best while climbing, just be careful shifting the front mech, they drop chains more often

Been running them on CX bike for couple of years, single chainring, traction is definitely a benefit, Pedal stroke feels “rounder”. No chain drops running narrow / wide.

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Ditto for me here too. Have them on all my bikes that go on dirt. Road is still normal round rings.

pio pace does not count as oval, they are basicly they are ovals with a 90 degree rotation

So I ran oval on all my bikes for about 3 years and have recently gone back to round due to availability and not feeling much of a benefit with oval. Also I looked at the cycling Dynamics profile from my favero Assioma pedals and when I would stand on a steep 10%, my power zone switched completely out of the optimal oval zone of the chainrings. I can include an image of what I’m talking about if anyone is interested.

Also the studies out there do not show much of benefit if any but from the studies, it doesn’t reduce effectiveness so if you like the feel of them, then use them, if not then don’t. Pretty simple.

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I’m sorry what? You were putting out 1100w before and chainrings gave you 1mph BS.

I dont have a scientific test zone, there may have been other factors at work there, it was a short sprint on a swction of road that I like to see how much power I can put out on. It was my first ride on oval chairings, it was for like 3-4 seconds. my garmin edge 510 may have given me bad results or my powermeter giving me bad results, or even a tail wind. I was just shairing an experience.

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Oh? Please tell more.

What FD are you using? When you say “…they drop chains more often…” it implies that you had drop chains before, on round rings, now you’re seeing more. Am I right?

Right now, with round rings, I am careful with front shifts (I make sure to unload the crank arm and then gently pedal over as I move up to the big ring, that’s how I thought everyone does it). Is this what you meant by being careful?

round rings dont, oval ones do, that is more chain drops

acasionaly you do drop chains, It is rare, It is usualy caused by a poorly adjusted deraliure, but it still does happen

Gotcha.

My experience, and those of many others I know including pro riders is that non-round rings hurt top sprint power. Very hard for me to prove, but, a lifetime of riding and training with power since PowerTap first came out (wired) and using rotor q’s for years, I finally moved off the q’s for round rings a couple years ago. Sprint power “seems” to have improved slightly. Again I can’t prove it as it could be something else. Certainly, to me, what’s way more important is how you get up to peak power. So maybe it’t the “snap” that is better with the round rings. The only thing I’m blessed with is neuromuscular ability. I can snap with the best of them so, I feel pretty confident in what I’m feeling and observing.

As far as speed goes, as you’ve indicated, that could be due to so many variables that saying rings added 1 mph is just not true. Not trying to be mean or harsh and again I can’t prove that. But, from experience, just not even close.

All this said I should add I really really wanted these things to due exactly the manufacturer says they do: more power at a lower HR. Unfortunately I’ve just not found either and am left thinking non-round rings are just more snake oil.