Osymetric Chainrings

[xbikeracer]

I have noticed in a few pictures that the Team Sky riders are riding the Osymetric Chain Rings, has anyone had any experince with these. I remember that Millar rode them as well as Bobby Julich. How are they different than the Rotors?

[Fibre-Lyte]

I know that Bradley Wiggins has been using them for what seems like an awfully long time, but other than that I don't know who else is. I certainly don't see many of them around, possibly because they're quite pricey (more than our carbon chainrings). The shape is completely different to Rotors. If you go on their website they'll explain why they are such an odd shape.

[xbikeracer]

I am from the US. How much are carbon chainrings? How about making some Osymetric rings out of carbon fiber? Does carbon make them stiffer?

[Fibre-Lyte]

Fairwheel bikes (your host) has them in their online store so you can see the prices there. I think the Osymmetric design will be patented or something similar so it's not likely we'd be doing any unless they asked.

[pritchet74]

The whole premise behind the o-chainrings is based on a study with the Festina team during the late 90's where they did testing that showed an increased power output with the o-chainrings. The problem is that these non-round chainrings don't produce accurate results with the SRM because the force applied isn't perpendicular to the strain gauges. This has been proven when riding with a SRM and a PowerTap at the same time.

I wouldn't waste the money.

[xbikeracer]

Would you buy a $60carbon fiber waterbottle cage and $2500 wheels? Seems like 300 bucks for 10% gain in power is cheap?

[Fibre-Lyte]

I'm not convinced by the 10 percent power gain. If that were true, wouldn't everybody be riding them?

[Ypsylon]

It also depends on how strong you are to begin with. I ride around at 100W, so 10% wouldn't really be that much, even if they existed. Could I push 400W it'd suddenly be way more interesting.

[pritchet74]

The 10% power gain doesn't exist. A 1% power gain doesn't exist either - not by using these rings. As mentioned above, they are marketed off of faulty research.

[mdeth1313]

they are marketed off of faulty research.

hmm, sounds like the tea-party was their marketing firm. (sorry, couldn't resist)

[Boonen]

I wonder who translated their website then ...

Surely there must be something to the idea of a variable gear ratio though? Having a larger gear at the point in your stroke where you're the strongest and a smaller gear ratio in the weaker point. In theory that sounds pretty good to me, weather or not O-Symmetric transferred that into practice in the right way I wouldn't know.

[Pat2A]

An interesting study to be read.
http://www.noncircularchainring.be/pdf/ ... se%202.pdf

[Fibre-Lyte]

If I wanted to get into a topical debate about the validity of non circular chainrings, my own opinion would be that they don't provide a power increase, but I do think they improve efficiency. So if you're doing long distance rides, such as a 12 hour time trial or a triathlon, I think they'll help your legs out (i.e. less lactate build up etc.) . I don't have any evidence to support that however. I do think a lot depends on your pedalling style as well.

[xbikeracer]

http://www.competitivecyclist.com/whats-new/the-curious-case-of-osymetric-chainrings.415.html this is a good review of the Osymetric Rings

[Fibre-Lyte]

Not a bad review but the comment about why they don't do a 53-39 made me smile. How can a 54 with the same profile be efficient but a 53 not? The set up review seems quite honest. One day I might give them a go but they're not cheap!