Boyd

Boyd's Feedback on iBike Accuracy

This was a ride I do many times in the summer when it can get very hot in South Carolina. It starts off with about an hour of rolling terrain to warm up, and then starts climbing for quite a ways. There are actually two climbs so it’s like doing two threshold intervals with about 10 minutes of recovery between each. When I get to the top then it’s a long downhill and a flat section for the last half hour to cool down on the way home. On this particular ride, at the request of members of a wattage forum, I did the ride with a Power Tap, iAero, and the new Quarq Cinqo. As you can see from the graphs, all three tracked each other very nicely and the accuracy of all three units makes it hard to distinguish any one power meter from the other two.

 

iAero – White Line;  Quarq CinqoGreen Line; Power Tap ProBlue Line

 

Power / Cadence / Wattage Differential (km 18 – 28)

 

 

 

REGRESSION ANALYSIS (R2)

 

The value R2 quantifies “goodness of fit” which in this case quantifies how close the wattage results of one power meter is to the wattage results of another.

 

R2 is a fraction between 0.0 and 1.0.

 

The higher the R2 (closer to 1.0) the closer the wattage results of one power meter came to the results of the power meter to which it is being compared. 

         In the R2 analysis from Boyd’s ride:

iBike Pro compared to the iBike Pro is 1.0 (or a perfect fit – results are an exact match)

                   iBike Pro compared to Quarq Cinco is .926

                               iBike Pro compared to Quarq Cinco is .887

 

JOHN - THIS BEGS FOR A CONCLUSION OR EXPLANATION ABOUT ACCURACY – HOW NO ONE POWER METER IS ACCURATE 100% OF THE TIME SO….

 

 

 

 

 

 


 

MORE DATA FROM BOYD’S 85 MILE RIDE

Power / Speed / Wattage Differential (km 18 – 28)

 

 

Power / Speed / Wattage Differential (km 24 – 34)

 

 

 

Power / Speed / Wattage Differential  (km 36 – 46)