Issues adding second bike (mtn bike)

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tex222
Posts: 17
Joined: Tue Oct 11, 2016 8:07 pm

Issues adding second bike (mtn bike)

Post by tex222 » Sat Aug 04, 2018 1:15 pm

I'm trying to add a second bike, a rigid 29er MTB with 29x2.35". The calibration process acts oddly with frequent stops in the updating of the power numbers as it increases (often goes to 0), then jumps up to a higher number than it was before. I finally got one to complete, connected it to isaac which had me go through the setup dialog and choose best accuracy(and I told it to use 29x2.3 tires and set the weights). On the second run, acted more sanely, but still had the going to zero for a while and the distance it took to get to 50 was more like the old, longer calibration period).
Attached are the 2 ride files - the calibration info is embedded right? Can ya'll see if things look reasonable and if ya'll can tell why the calibration behaves oddly. I'll note:
    the garmin says the battery on the speed and cadence sensors is fine.
      the speed sensor is on the rear hub as the front hub is a dynamo and seems to mess up the speed sensor

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Sat Aug 04, 2018 1:18 pm

      Forgot the attachments!
      Attachments
      PP_2018_08_04_0938_0_Miles_HiDef.ibr
      second calibration
      (11.78 KiB) Downloaded 3 times
      PP_2018_08_04_0938_0_Miles_HiDef - firstCal.ibr
      first successful calibration before customizing weight/tires in Isaac
      (11.73 KiB) Downloaded 2 times

      Velocomp
      Velocomp CEO
      Posts: 5237
      Joined: Fri Jan 11, 2008 9:43 am

      Re: Issues adding second bike (mtn bike)

      Post by Velocomp » Sat Aug 04, 2018 4:23 pm

      It looks like things are OK but your ride file is only 1 minute long.

      Please do a longer ride and post that one.
      John Hamann

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Sun Aug 05, 2018 4:05 pm

      Here are 2 parts of a ride yesterday. I actually had turned off the connection to the powerpod from the garmin a couple of miles into the ride as it was just showing 0 most of the time except for a couple of odd spikes on basically flat urban road riding on the MTB.
      The 15 mile ride is the first part, with urban road riding in the flats then going up hill to about 1200 ft, then the heavy braking downhill was on some single track. Then going up hill on the road - surprised it says I did alot coasting on that uphill as that can't be true!
      Also, wasn't a windy day I believe - seems to say it was 15+mph alot of the time and I would remember that!

      The second ride file is the same ride, looks more reasonable in that I don't see coasting on uphill climbs but that 750 watt spike on a downhill seems off. My rigid MTB is not high geared so I almost always spin out on downhills.
      Attachments
      PP_2018_08_04_1040_15_Miles_HiDef.ibr
      (827.01 KiB) Downloaded 3 times
      PP_2018_08_04_1442_16_Miles_HiDef.ibr
      (825.87 KiB) Downloaded 7 times

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Mon Aug 06, 2018 5:29 pm

      I'll note that after the initial long climb, for the singletrack descent I reduced tire pressure a bit....

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Tue Aug 07, 2018 1:01 pm

      OK, more information:
      • the garmin speed sensor auto calibration had 2267mm, while I measure it(at 30PSI) as 2355
      At about 20PSI, I measure it at 2351mm. So I wonder if this is part of the issue, especially the data about high wind speed? Presumably the bad calibration is due to my rear hub being a rohloff - perhaps the calibration makes some assumption about the diameter of the hub?

      So would changing this in the speed sensor mean I need to do a new recalibration?

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Tue Aug 07, 2018 6:13 pm

      OK. After changing the speed sensor to the manual wheel size. I went into isaac and also changed the powerstroke pedal position to not set and applied that to hopefully force a recalibration.
      Took off and it was doing a recalibration as expected. On the outbound leg, had an initial couple of 1 second periods where power went to 0 even though the LED still blinking. Power would come back, incremented. And it was incrementing slowly, in the old, long calibration O&B ride style.
      Once I got to 50, turned around and headed back. On the return leg had multiple very long periods of where it went to 0 power. In the end I had to ride past the starting point for several blocks and still didn't get to 100 (was in the 90's). So turned around went home since obviously not happy.

      Is there any way to tell what is going on with using the 2nd bike since when I work on the first bike it never has this calibration issue.
      Why would it go to 0 on the garmin during the calibration?

      Velocomp
      Velocomp CEO
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      Re: Issues adding second bike (mtn bike)

      Post by Velocomp » Tue Aug 07, 2018 6:16 pm

      If you coasted at any point during the cal ride, power will go to zero. When you resume pedaling the counter will continue. This is not an issue.
      John Hamann

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Wed Aug 08, 2018 2:33 am

      I wasn't coasting during the periods where power was shown as 0 instead of incrementing......

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Thu Aug 09, 2018 11:56 am

      I'll re-iterate that this is during the O&B calibration - on my gravel bike I do not believe I ever see the countup from 1 to 100 ever go to zero during the calibration ride.

      Velocomp
      Velocomp CEO
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      Re: Issues adding second bike (mtn bike)

      Post by Velocomp » Thu Aug 09, 2018 12:10 pm

      Check your cadence sensor. If cadence drops to zero, for whatever reason, the 0-100 indicator will drop to zero.

      In any event, the annoyance of the counter doesn't affect the calibration result.
      John Hamann

      tex222
      Posts: 17
      Joined: Tue Oct 11, 2016 8:07 pm

      Re: Issues adding second bike (mtn bike)

      Post by tex222 » Thu Aug 09, 2018 12:30 pm

      I guess I'll switch out the batteries though the garmin says the batteries are ok. I guess I could also watch the cadence numbers to see if they go to zero during calibration while pedalling.
      I'm wondering if my dynamo front hub could be causing any kind of interference - I've read anecdotal things about people saying they've had issues with garmin sensors but nothing authoritative about this. The dynamo is why my speed sensor is on the rear wheel as the magnets in the dynamo make the sensor not work on the front.

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