Those chainrings seems pretty cool and functional , anyone got some experience with them?
i want try something but the cost is too expensive , do you guys know a cheeper version ?
(My crankset is FSA tea, issue full carbon compact 50t)

Some people like them. Most people don't. Their lack of general popularity pretty much sums up the situation. I wouldn't waste my money on them...again.

My vintage Cannondale R400 from 1989 has a Shimano "Biopace" Chainring, which is oval.

Can't say I really notice the difference. I don't dislike it in any case. I woudln't spend extra money on it.

It was supposed to be better for the knees, but it never really took off. Some pro's even ride oval chainrings I think, so it might just be personal preference.

I have a bike with Biopace. Going from one bike to another, it does feel a bit different. But it's hard to notice. It feels smooth and almost like the cranks are shorter or something.

Anyway they are designed differently than other oval chainrings. They're more egg shaped. Might be able to get some on ebay.

I dislike oval chainrings because they make it hard to adjust the front derailleur correctly.

Rotor Q rings from a high end Spanish Company , has been used by professionals .

Buy and Try if you are curious enough, rather than rely on the opinions of Others ..

Rotor Bike Components

If after trying them, You dont like them then re sell them over the web.

Oval chainrings is a "novel" idea that has been coming around every 20 years or so for the last century. The exact shape and orientation keeps changing, and after a short time the phase is over and the idea goes dormant again.

And pops up as a BF topic every few months or so...

Lucky, if it is that long. Especially come high UCI racing season.

I bought a used Raleigh racing bike with 531c tubing that has Biopace rings in front. Seems pretty nice to me. Smooth. I have another road bike with regular chainrings. I don't "miss" the Biopace rings when I'm riding the other road bike. I don't even consciously notice one or the other. However, I enjoy the smoothness of the Biopace.

They're "functional" in the sense that they at least don't fail to be chainrings.

Thanks guys for those interesting infos , looking for more owners feedback.
On ebay i found a trademark called DOVAL. It is an ibrid from oval and asymmetric and cheeper as well , i think i'll give a try into this one (if my crankset allow me to do that).

I don't have the oval rings but was looking into them as the concept makes a lot of sense from a mathematical/Engineering point of view. Then the cost took away my interest as it seemed excessive to me.
Post up if you get them

Nonsense. I have 4 bikes with Q-rings and it is quite simple

He's right; just set the FD for the highest part of the large chainring and it works fine...

FWIW, we used to rotate Biopace rings one bolt hole clockwise; they seemed to feel just a little bit better that way...

If you have junior gear restrictions - they give you an effective larger gear.

Sheldon Brown has a comprhensive article about these. Here are a few things he talks about. See articlr for full text.

Biopace Chainwheels

What Are They Good For?
Biopace chainwheels are particularly suitable for touring cyclists and time trialists, or any application that involves a steady, fairly constant cadence. They allow healthy, efficient pedaling at slower cadences than is possible with round chainwheels. They are especially suitable for triathletes and mountain bikers. The triathlete benefits because the motion is a little bit closer to that of running, making the transition easier.

The mountain biker particularly benefits, because the Biopace design somewhat smooths out the delivery of power to the rear wheel. In climbing on loose surfaces, the limiting factor is often traction.

[h=3]The Cadence Issue[/h]The marketers of Biopace made a crucial error of judgment: too much information. In particular, they mentioned that the Biopace design was optimized for cadences of about 90 rpm and slower. Many readers interpreted this as an indication that Biopace chainrings would somehow interfere with pedaling faster than that. This perception caused a bit of a self-fulfilling prophecy, and the Conventional Wisdom arose that Biopace was bad for high-performance cyclists for this reason. I [Sheldon] used to believe this myself, but I rode them anyway because I appreciated their other virtues.


[h=3]Biopace and Fixed Gear[/h]People are often astonished to learn that I ride Biopace chainrings on fixed-gear bikes.
[h=3]Biopace Combinations[/h]The usual stock combinations with Biopace chainrings were 48-38-28 or 46-36-26 for a wide-step triple; 52-42 for a racing double. A half-step-plus-grannies combination is possible with 50T-46T or 48T-44T for the two outer chainwheels and a 28T or 26T inner chainwheel. This works well with an 11-13-16-19-23-28-34 cassette -- a custom combination, to be sure

[h=3]Orientation[/h]For installing Biopace chainrings, the orientation should generally be preserved. Each Biopace chainring has an "indexing mark." This is a small tab pointing inward toward the middle of the chainring.
Mixing Biopace and Round Chainwheels

It is possible to mix Biopace and round chainwheels on the same crankset, but I [Sheldon] would not recommend it.

[h=3]Conclusion[/h]Cheers

Can't imagine why; we used to do it all the time.

Hot set-up was Biopace large ring, rotated one bolt clockwise, round middle gear and round stainless steel "granny".

Worked great...