New Calibration Ride...Does it look ok?

[rsmithersfitness]

Now that the weather has warmed up I decided to do some Coast Downs and a Calibration Ride. Coach Boyd, I was wondering if when you get a chance you could take a look at it and let me know what you think. The roads around here are pretty rough in some spots. My crr was at .0085 and cda at .243. Thank you for the help!

[rsmithersfitness]

bump

[rruff]

I haven't looked at your file, but you should be looking for a Crr in the .004-.006 range, and a CdA in the .3-.4 range. The iBike tries to extract an exponential constant (Aero) and a linear constant (Fric) based on the shape of your coastdown curves. So it isn't that strange for one to be too high and the other too low, but still add up to total drag figure that is correct for the coastdown. You need an accurate value for each though, if you want good power values in all riding conditions.

Don't do coastdowns on rough roads.

BTW... you'll get more comments if you post a screenshoot of your coast-down and cal ride data.

[coachboyd]

Sorry it took me so long to see this. I looked at the thread on my phone and then forgot that I had read it.

One thing that jumps out at me is that you have a positive riding tilt. Almost everybody has a riding tilt that is a negative number. It just makes sense that your stem flexes downward as you put pressure on the bars. This may make me wonder if your tilt was a little off when you did the coastdowns and if that is causing the high crr and low cda. When I changed the crr to .0055, it gave me a cda of .385 (right around what I would expect to see). If you would like I can send you that profile.

rruff is right though. Make sure that you do your coastdowns on a smooth road. There is so much data being processed in a coastdown, you want the input to be as clean as possible.

It might be worth it to try the coastdowns and cal ride one more time. I really want to see your riding tilt again for the cal ride and see if this could be the cause of the issue.