Newton+ profile
Posted: Fri Aug 24, 2012 4:49 pm
I generally get very different results from my Newton+ as compared to my Quarq on the same bike and on the same ride. I've been using iBikes/iAeros for over 5 years and have set up innumerable profiles, so I'm puzzled why I am getting these differences. I did check my profiles against the guidelines published on this forum, and two do seem out of whack: (1) CdA on the hoods should be 0.28 to 0.45, and I got .589; (2) wind scaling factor for handlebars should be 1.3 to 4.5, and I got 1.125. Everything else is within the recommended ranges. I have no idea what I would do differently to get different CdA and wind scaling numbers as I believe I performed everything correctly.
To get my profiles, I completed about 9 coast-downs and an extra long Cal ride. My understanding is that once I've uploaded the coast-downs and Cal ride, the Newton software will compute aerodynamic and frictional drag coefficients based on the DFPM and iAero data captured during the calibration ride. Also I assumed that the Boyd-in-a-box magic would happen to eliminate further tweaking of the coefficients.
Here are some results from the attached ride file that I find disturbing. I am highly inclined to believe that the Quarq DFPM numbers are more accurate:
Newton
Avg Power - 183.7
Max Power - 980
NP - 232W
IF - 0.85
TSS - 309
Quarq DFPM
Avg Power - 158.7
Max Power - 728
NP - 201W
IF - 0.73
TSS - 232
To get my profiles, I completed about 9 coast-downs and an extra long Cal ride. My understanding is that once I've uploaded the coast-downs and Cal ride, the Newton software will compute aerodynamic and frictional drag coefficients based on the DFPM and iAero data captured during the calibration ride. Also I assumed that the Boyd-in-a-box magic would happen to eliminate further tweaking of the coefficients.
Here are some results from the attached ride file that I find disturbing. I am highly inclined to believe that the Quarq DFPM numbers are more accurate:
Newton
Avg Power - 183.7
Max Power - 980
NP - 232W
IF - 0.85
TSS - 309
Quarq DFPM
Avg Power - 158.7
Max Power - 728
NP - 201W
IF - 0.73
TSS - 232