Item # OSY0004

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  • Black, 110x38 ($169.99)
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Item # OSY0004

More power with less effort.

Not quite an oval, and certainly not an ellipse, the Osymetric Chainring Compact is its own shape — and we're happy for that. Oysmetric delivers greater efficiency, increased power, and requires less user effort than standard round rings.

Now, before we get into explaining the Osymetric, we want you to abandon any preconceptions or memory comparisons of failed experiments like Biopace. This isn't to say that those engineers were wrong to pursue these designs, they simply never perfected the technology. We think that this is due to a fear of breaking free from the parameters and presets of what cycling componentry is supposed to look like. However, Osyemtric has realized that the best look for a bike is crossing over the finish line in first place. That's why Osymetric isn't afraid to appear obtuse in its aesthetic.

The concept behind Osymetric is relatively easy to grasp. On a standard chainring, power isn't applied equally throughout a revolution of the crankarm. For simplicity's sake, let's divide a revolution into four quadrants. We'll call twelve and six o'clock Top Dead Center (TDC) and Bottom Dead Center (BDC), respectively. The horizontal position of three o'clock can be called just that. It is within the angle between the horizontal position and BDC, that power is most predominately exerted. However, the acute radii between the horizontal position and TDC and BDC are relative dead spots for power. Osymetric's shape directly reflects this data. It works on the objective of minimizing the time spent in dead spots, while maximizing the time spent within the radii of efficient power exertion -- horizontal. Basically, this means that, as the operator, you can apply more force while spending less energy. In fact, Osymetric's design minimizes torque and effort by creating a nearly constant angular velocity. This means that while your gear inches are maximized and extended in the power position, the ring changes shape at the dead spot to speed you back to the power position.

Osymetric's testing has shown that its Twincam shaped rings provide an average of 10% increase in watts per revolution. Also, with the near elimination of 'rest' in dead spots, Osymetric claims an average of 12% reduction in lactic acid buildup. And despite the Twincam shape, Osymetric does not require a special chain. Osymetric acknowledges that it takes around one hour for 95% of users to 'get used to it.' So, we suggest resigning your final judgement till your muscle memory adjusts.

The Osymetric Chainring Compact 110mm BCD is available in the color Black and in 38, 50, and 52 tooth options. Please note that this is a compact, 110mm BCD chainring. We are also offering the Osymetric in a standard chainring size.

Tech Specs

Number of Rings:
38, 50, 52 t
Bolt Circle Diameter:
110 mm
Compatible Components:
compact Shimano/SRAM cranksets
Recommended Use:
road cycling and racing
Manufacturer Warranty:

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38T may be too small for Osymetric shape

  • Familiarity: I've put it through the wringer

I bought this ring for my 1x10 city bike conversion. There's no doubt it works- when I hit the hills on my normal route, I don't feel anywhere near the "burn" in my quads that I'm used to, and my knees feel much less stressed. However, with a chainring this small, the transition from large radius to small radius is quite abrupt, so when I'm using anything but the 2 middle cassette cogs, the chain catches, then drops onto the chainring teeth...so all I hear is ker-chink, ker-chink, ker-chink as I pedal. The problem gets worse toward the top and bottom of the cassette, where the chain angle is more significant. I'm using a new Shimano XT cassette and chain, the chainline is perfect, and my chainstays are fairly long...it sure seems like an issue specific to this product.

I suspect that it wouldn't be a problem with larger chainrings, or if they had bothered to profile the teeth at all.

Is the 38T 110BCD ring for outer or inner...

Is the 38T 110BCD ring for outer or inner placement, or doesn't it matter?

It's for inner. There is an accompanying 50T or 52T for outer use with the 38.

It turns out that it doesn't matter- the chainring bolt holes are not recessed on either side.