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Favero has made public their new IAV Power system.
This is an entirely new calculation algorithm for Favero and it bases power calculation on Instantaneous Angular Velocity (IAV).
Favero believes they are the only power meter pedal company currently able to deliver this calculation because of their pre-existing, inbuilt, high-precision gyroscope.
So What?
It’s a big deal.
Favero claims that IAV increases their accuracy to +/-1 % which matches the claimed accuracy of Garmin’s Vector 3 (only v3). This is an improvement from the current +/-2% accuracy of the ASSIOMA.
And there’s more…which should benefit many types of riders. The following types of riders with different pedalling styles and/or equipment should also see better accuracy:
- Piston-like pedal action;
- Standing on pedals when climbing; and
- Users of elliptical chain-rings of any degree of ovality (me…yay!).
These kinds of sources of error from technique or kit could equally be experienced on any kind of power meter that is located on parts that rotate with the cranks.
Commentary
Many of us switched to oval chainrings to eliminate dead spots in our pedalling technique and also to get a bit of potentially, free power. From my own experience, many bike setups showed increased power. Yet was this REAL increased power or was it incorrect measurement? ie does an oval increase your recorded power by 2% but overestimate by 2% Those of you with a PowerTap G3 will, of course, know the truth either way!
The following research paper which Favero sent me, shows that one of the most oval rings available, OSYMETRIC 110mm – 50R, can lead to incorrect measurement in some circumstances of 4.5%.
Research Paper: 3mb Influence of Angular Velocity of Pedaling on the Accuracy of the Measurement of Cyclist Power
The paper also suggests circular rings could lead to a 0.5% over-estimation when climbing a 5% grade.
Perhaps also there could be a 1.5% under-estimation on indoor trainers with circular rings.
The study finds greater errors on road usage with oval rings of +2% to +4% but those same errors lessen indoors to about +1%. In my own anecdotal tests with ovals, I tentatively and conveniently found +3% errors in the middle of that range.
The document linked to above is interesting reading although I do note, “…to simulate the power applied by the cyclist with both legs, the power measured by the single pedal was doubled….“. (Doubling should be OK for this purpose if you think about it).
The theory in the document also makes sense to me...let’s see how it pans out in some tests.
Price & Availability
It’s free to existing ASSIOMA users (new users too!!) and will be available to download via the app on 2nd May 2018.
