Post ride adjustment and overall accuracy

[Brodirt]

As I posted earlier in regard to tne NaN readings when I download data post ride from my Iaero and run an analysis I am getting very different numbers.

My during ride data might show avg. watts of 160, my pre-analysis download 152 and then when I run the analysis 182.

Is this indicative of a bad profile? If not, how can I trust my on bike data readout as being correct?

[iodaniell]

As I posted earlier in regard to tne NaN readings when I download data post ride from my Iaero and run an analysis I am getting very different numbers.

My during ride data might show avg. watts of 160, my pre-analysis download 152 and then when I run the analysis 182.

Is this indicative of a bad profile? If not, how can I trust my on bike data readout as being correct?

What you are seeing could be:

1) Bad pre-ride process
2) Bad calibration profile
3) Both 1 and 2

Pre-ride Process
-------------------
Each ride, you need to:

1- set the bike up for the ride, first (water bottles, miscellaneous equipment, tires pumped to desired pressure)
2- let the device acclimate to the environment (imho, this is the hardest for some of us to do)
3- set & verify the tilt (don't assume that the tilt is spot on--verify it)
4- zero the wind offset (if this is done in somewhat windy conditions, position the device so that the wind hits it from the side and not from the front or back)

Once the pre-ride process is complete DO NOT change the conditions.

======================================
Bad calibration profile
--------------------------
Re-do the calibration under proper environmental conditions (i.e., low to no wind, low to no traffic, road surface similar to where you ride most of the time, no rain):

1- Follow the pre-ride process
2- Capture 10 or more coast-downs
3- Capture a 2 mile (or more) out & back (minimum of 4 miles, total, travelled)

If you've followed the above, you should get better accuracy and consistency. If not, you may have a hardware problem or a problem where the bike is changing as you ride (i.e., inner tubes are leaking over the course of a ride, device mount is not "rock solid", handle bars rotating during a ride, magnets are not secure enough or placed close enough to sensors, etc.)

[Brodirt]

Pre ride process is good. I zero wind each ride. I tilt calibrate 90% of the time as well. My profile consists of 8 coast downs, of which I disposed of 2, and an 8 mile out and back. It seems to me to be a good profile.

I do not pump tires up to consistent pressure on each and every ride, but I am within 5-10 psi for both front and back, I pump up every weekend. I am not getting any kind of weird hill readings that would indicate either tire being low enough to alter the tilt, and tilt calibrating would account for this on each ride. Maybe I need to do tilt calibrations with me sitting on the bike as well....never though of that until just now, but if this device needs that kind of accuracy in calibration I think its a bit insane.

I dont know what acclimitization would really mean. Im not starting up my ride in atop Mt. Washington and then rolling down to the valley to start my ride. These days its pretty consistent temp and humidity inside and out wherever the unit goes. Again, if its that nit picky that the humidity and temp in my not connected garage being slightly different than the outside temp and humidity we are getting a bit insane....after all, most rides the temp and humidity are far different in the last half hour than the first half hour, wouldnt this completely screw up all the results than?

[iodaniell]

I dont know what acclimitization would really mean. Im not starting up my ride in atop Mt. Washington and then rolling down to the valley to start my ride. These days its pretty consistent temp and humidity inside and out wherever the unit goes. Again, if its that nit picky that the humidity and temp in my not connected garage being slightly different than the outside temp and humidity we are getting a bit insane....after all, most rides the temp and humidity are far different in the last half hour than the first half hour, wouldnt this completely screw up all the results than?

Velocomp has stated that if the temperature changes +/-20 degrees during a ride, it could affect your numbers. I believe that all you would need to do is recheck your tilt and wind offset.

If your pre-ride process is good, I'd consider re-running calibration.