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I'm thinking about trying the famous Osymetric chainrings, and I would like to use it with a power2max Classic power meter.

I just want to be sure that there are compatible? It's very difficult to have answers in bike shops because Osymetric chainrings are not that famous here (Montreal).

Any help would be appreciated.

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Power2Max say:

Changing cranks or chain rings does not affect calibration. You can also use oval chain rings (e.g., Rotor Q-Rings, Osymetric, etc). Please note: compact (110 mm) aero chain rings (such as Rotor aero Q Rings) are not compatible with power2max Classic, but are compatible with Type S.

So, yes.

That said, does it really matter all that much if they don't? Stages reckon there's a +4-5% error when using them on their power meters, but recommend you just adjust your threshold accordingly. Once that's done you can carry on as normal, the absolute numbers aren't all that important, the zones you define around them are what matters.

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  • Absolute accuracy (rather than relative accuracy) can matter depending on what you're doing. For example, if you are trying to estimate aerodynamic or rolling resistance, you'll need absolute accuracy across the range of speeds you're likely to experience.
    – R. Chung
    Commented Jul 28, 2015 at 4:04
  • I suppose so, but that's rather an edge case, you can still compare different positions, tires, etc. against each other as long as you stick with the same chain rings. The only thing I can see this being an issue for is of you want to compare power output for oval vs round chain rings, that wouldn't be possible on a power meter that wasn't corrected for them.
    – alex
    Commented Jul 28, 2015 at 5:20
  • That was just an example -- there are other times when absolute accuracy matters. It's just that training typically isn't one of the uses for a power meter that requires very high data fidelity; that's why people have been able to train effectively without one. There are, however, things that would be very difficult to do without a power meter, and these generally require accuracy. An example is VO2Max testing with a ramp protocol, since the ramps need to be of known and equal size.
    – R. Chung
    Commented Jul 28, 2015 at 6:08
  • Ok thanks, it's just I've never manipulated any of these so I wasn't sure about how it works. Thanks!
    – Léo Davesne
    Commented Jul 28, 2015 at 18:07

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