As I was mud plugging away on my ride today I had a sudden realisation that ovalised chainrings would make a huge amount of sense with 1x whatever set-ups, where I find the only problems I ever have are going up steep techy sections, low cadence where you’re in danger of stalling at tdc. Ovalised chainrings should help a bit. A quick google search suggests that I’m not the first to have thought of this, leonardi factory do one though it comes with a complicated chain device and I’m not sure if they’re available in uk.

So, has anyone tried it? Are any others available, and why wouldn’t it work with (most) normal chain devices with the kind of plastic front mech thingy

Just seen that betd do them…

http://sheldonbrown.com/biopace.html

Now I’m very confused. So are people using them in the biopace fashion or the other way round

The other way round.

Like much of the info on Sheldon Brown that seems quite an outdated article. The longer it’s left the less relevant it all becomes!

no idea, just pointing out the concept is quite common.

Look up elliptical instead of oval and you might find some more sources.

The rear mech has to deal with the fact that the chain is moving vertically while shifting. Can it do that?

(Sounds to me like really you want a SS).

Shelton says elliptical chain rings (except in the Biopace position) “tend to hurt people’s knees” but he doesn’t quote any sources

Rotor, who make chain rings in the non Biopace setup, say Biopace can cause knee pain.

Go figure.

Take a look at this:

http://www.osymetric.com/content/view/30/60/lang,en/

I have them on my new MTB and now I just can’t go back to round chainrings.
They are specially designed to reduce the dead spot when pedalling and optimized for the movement of the leg.

They also reduce knee pain compared to a round setup because of their unique design.

The rear mech has to deal with the fact that the chain is moving vertically while shifting. Can it do that?

Yes it does work perfectly as I’m running them with a 3×9 setup.

Do you mean “just can’t”?

Do you mean “just can’t”?

Yes, edited 🙂

If I may add this : I noticed these chainrings help significantly to go over obstacles during technical climbs, and actually allowed me to climb with a smaller cog.

Goldtech jobbie.
Only used SS, but highly recomended.
Feels like cheating.

IMAG0335 by pten2106, on Flickr