Not self correcting, maybe tilt too far off?

[nreimche]

Hi e'ry one,
I upgraded to Gen 3 a month or 2 ago, accept that I had to get a new mount. The first few rides with the Gen 3 were ok, but since the mount was slightly turned a bit, too much clockwise, I turned it back counter clockwise. I decided not to worry about doing tilt calibrations, pressuming that it would self correct, yet my watts have been reading 100 or more watts off. I thought it could be the battery, which, I changed. I, also, tried IBIKE 3 for windows, but the power was fairly close after analysis. I double checked my profile.
This was the long story, but I'll jump to my question now: "I checked the tilt, which was off by a few percent. Would that be too much to tilt to self correct? Or is my NEW GEN 3 broken in the windport, accelerometer, because e'ry thing else seems fine, when compared to my POLAR power meter?". Even the wind speed shows up reasonably, so again, could it still be the tilt? I even tried a few coastdowns and a 4 mile cal ride, which returned a bad cal ride, which caused the 'send to ibike' option to be unhighlighted in the download CD's and 4 mile ride. The fric numbers were the highest I've seen, at 26 and the aero numbers around 2 or less, with their decimals in their respective places. Thanks.

[Velocomp]

Please send a ride file to atimmer@velocomp.com. Forward your question to him, too.

[coachboyd]

If your tilt is off by a few percent this will really throw off your coastdowns and give you high friction numbers.

The coastdowns use the "raw" tilt calibration. In other words, if you put the bike on your garage floor and you see 3% tilt, this is what will be seen with the coastdown no matter how long you ride. The out and bike ride does the same because it's trying to measure how far the tilt deviates from the barometric elevation (riding tilt). If the tilt is +3% off, then you will show a riding tilt of approximately +2.6% (and that is probably why the software won't let you send this profile to your iBike)

When you are riding, you will see a tilt that is 3% higher for the first five minutes of the ride. Then for power calculation purposes, the tilt correction algorithm will kick in. Immediately before doing coastdowns and a 4 mile ride it is always best to do a tilt calibration and a wind offset

[nreimche]

I did the tilt cal, I used the same profile from when my Ibike worked, I even experimented w/ the est cda feature, I let the Ibike acclimate outside for a while, I did the wind offset to zero after that, but something is wrong still? The speed matched up well w/ my polar cs600, the cadence was somewhat quicker to respond to cadence changes then the cs600, but the watts were reading 300+(guessed average) even though my HR was 140 average or so bpm for long periods. Now I can usually ride at 170-190 watts w/ a HR of 140 or so. Here is the last ride I did w/ all the good info, since I didn't change much in regards to clothing, position, wheels, etc. PLEASE HELP!

Also the watts never corrected for the entire 2 hour 20 some mins.

Another way look at the problem is the fact that I did a fit test w/ the same profile and scored a level 6, but lately I have been above my test results at very low HR's for hours. I must have a broken unit, unless someoene can troubleshoot! The 4 mile cal ride is attached too.

iBike_05_03_2009_1405_40_Miles.csv

Snowbowl climb w/ride from home then back w/ some short hard efforts.

(1.76 MiB) Downloaded 323 times

090412_1821_cal_ride_AB7E101B.ibcd4m

4 mile cal ride at Wupatki National monument

(542.76 KiB) Downloaded 298 times

[coachboyd]

I think the problem was that your wind scaling was off, meaning it looks like you had a headwind the whole time. The tilt reading looks great throughout the entire ride.

I gave you a new wind scaling number and put the cda to what it was before. I also changed your crr to a more real world number. I have attached the same file here with the new profile attached. Open this file, then go to profiles->edit profiles->and hit the extract button. The profile will now be shown and you can send it to your iBike. Then you will be good to go from here on.

[nreimche]

Just a few more things: I double checked the trainer mode, it was off; my riding tilt(-.3%), wind scaling(1.409), cda(.401), crr(.0094 winter clothing), weight (I could lose 10 more, lol!), wheel circ(2094 for700 23c), and cm(1.02) were all in the suggested ranges that have been mentioned in another thread of this forum. Thanks.

[nreimche]

Ok thanks coachboyd, I'll try out the tweeks and new profile. My guess is that by twisting the unit counter clockwise (to make the Ibike point straight) w/out doing another 4 mile cal ride, must've made the wind seem stronger to the Ibike. In other words, the wind is going in the wind port more directly, thus increasing my watts. Does that sound correct?

[coachboyd]

Yep, that sounds about right to be. . .Also, in your cal ride there was some anomalies at the turnaround with both wind and elevation. Fortunately I was able to look at the file and figure out the wind scaling from there.

[nreimche]

Good job Coachboyd! The ride looks good in Ibike 3, but I'll do another set of CD's and 4 mile ride when the winds get calm and/or I ride at Wupatki National Monument. Wupatki has very little traffic a fairly flat/straight section, quite long, and even a bowl or 2 for CD's. The winds are possibly even more stable then Flagstaff, Az. Keep up the great feedback, e'ry one!