One of the ongoing issues I have had is getting meaning ful profiles set up. I have had an ibike for 3 years and currently on GenIII.
I have followed the set up and calibration process to the letter, doing more coast downs and calibration rides than you can shake a stick at. I always need the tweaking skills of Boyd though to sort things out.
If I were to get the use of a power tap wheel, my understanding is that I can run both the ibike and powertap, can I calibrate the Ibike for all my bike set up's? Granted the rear wheel will change when I don't use the borrowed powertap.
I have collected a large amount of data using my No. 1 race bike over the last 9 months on Gen III, but want to move back onto my winter training bike and am concerned that re-creating a new profile on a different bike will cause me problems e.g. if the profile creation is not spot on, then what I am currently seeing as 200W may be 175W on the training bike.
So - in the interests of absolute parity between bikes would obtaining a power tap to calibrate help me?
Ben
Calibration with a DFPM
-
- Site Admin
- Posts: 392
- Joined: Fri Jan 11, 2008 8:52 am
- Location: Durham, NC
Re: Calibration with a DFPM
Probably so. One of the big benefits of calibrating with a DFPM is that you end up integrating much more data into the measurement of CdA and Crr. Coast-downs only last a few seconds, which is why it is good to do several. Also, the DFPM calibration method is more tolerant of the wind conditions--the less wind the better when doing coast-downs.benlane wrote:So - in the interests of absolute parity between bikes would obtaining a power tap to calibrate help me?
Travis
-
- Site Admin
- Posts: 392
- Joined: Fri Jan 11, 2008 8:52 am
- Location: Durham, NC
Re: Calibration with a DFPM
It does require the iAero.tommyturbo wrote:Travis,
I have friends with Powertaps, but have never really thought about borrowing one for calibration. Can this method be used with an iPro, or only an iAero?
Re: Calibration with a DFPM
For what it's worth, I've had much better results just doing a regular iBike calibration procedure without a Powertap, but using double the distance (e.g 4 mile instead of 2 mile cal ride and then 12 x coastdowns). Then I use the Powertap to check the results.
On my summer bike I never had to tweak the profile at all. Every ride is within 2 watts average of the Powertap (usually sub 1 watt difference)
On my winter bike, I did several rides with the Powertap and iBike over varying terrain and simply tweaked the profile slightly to match.
I could never get the PT method to work (V4.00 firmware). It came out with the worst results I had seen.
So in my experience, a PT is a useful tool for checking results/tweaking but not for calibrating.
On my summer bike I never had to tweak the profile at all. Every ride is within 2 watts average of the Powertap (usually sub 1 watt difference)
On my winter bike, I did several rides with the Powertap and iBike over varying terrain and simply tweaked the profile slightly to match.
I could never get the PT method to work (V4.00 firmware). It came out with the worst results I had seen.
So in my experience, a PT is a useful tool for checking results/tweaking but not for calibrating.
- lorduintah
- Posts: 642
- Joined: Fri Jan 11, 2008 9:37 am
- Location: Plymouth, MN
Re: Calibration with a DFPM
The most solid calibration ride I have personally seen was an 8 mile (4/4) ride - the analysis came back as a straight line plot - usually I see plenty of bumps (deviations) from that corrected slope line. I was in a lucky place where there is no interference from traffic on a fairly calm day. The 2 mile calibrations tend to have too much noise in them for whatever reason.
I also tend to do at least 9 CDs.
Tom
I also tend to do at least 9 CDs.
Tom
-
- Posts: 14
- Joined: Fri Oct 30, 2009 2:20 am
- Location: NC
Re: Calibration with a DFPM
About this eight-mile cal ride, would I simply keep riding at the end of the first mile, ignore the power meter as it flashes the 'bac' message, and continue to ride for three miles before turning around?
- lorduintah
- Posts: 642
- Joined: Fri Jan 11, 2008 9:37 am
- Location: Plymouth, MN
Re: Calibration with a DFPM
Yes, whatever length you choose to ride - you can ignore the flashing, unless you slow down below 8 mph. That is the internal check for the iBike to sense a turnaround.
It does not have to be 8, but 2 is really on the short side. I just happen to have a 4 mile stretch that I can go without any stops or traffic.
Tom
It does not have to be 8, but 2 is really on the short side. I just happen to have a 4 mile stretch that I can go without any stops or traffic.
Tom