910xt system update/Stages PM

Danielle Santucci

Coaches, could a software update on my Garmin 910 skew my Stages power numbers? I'm on week 17 of the advanced HIM plan. On Saturday, I updated my Garmin a few hours before my long ride. When I turned the Garmin on, it detected my PM and it asked to recalibrate. I clicked yes and went on my way. Outside, it seemed off (kept dropping cadence data and the avg watts were up and down). I tried to stick to my z4 intervals as best I could, but with the data being all over the place and the multiple stops (darn stop signs/lights) of riding outside I couldn't seem to stay within my zones. I relied more on my HR, than power, to complete the intervals.

The following day, I put my bike on the trainer for the 150' ride with the hope of having a strong, consistent z3 ride. After the initial 30' warmup I got into the main set. Geared down to find my Z3 ( 135-148w). This is when I figured something was wrong. Riding these watts for 2hrs was not an option...it was like riding on air-my HR never went over 100. So I added gear,, my HR started to rise to a very comfortable 118-124. The watts I was pushing in this gear were way over my Z4, I averaged 212w for the entire main set at a HR that is typical to Z2 riding.

Any ideas about what is going on? My plan has me testing this week and I'm concerned I will have false readings/data leading up to Raleigh.

Thanks,
Danielle

Mike Neas

Hi Danielle,

I had the same problem with my Stages PM.  I noticed the calibration value creeping up from 892 to well over 1300.  Felt awesome looking at a 300W reading...but HR just wasn't where it should have been for that effort.  I tried updating the firmware on the Stages (with an IPhone) and that did not fix it.  Firmware updated just fine, but unit was still reading all over the map.  I ended up taking it back to my LBS where I bought it and they confirmed it was a bad Stages unit.  They had another one at the shop in a couple of days and replaced it for free.  Mine routinely calibrates since then at 892-895 with no hiccups.

Hope this helps.  Good luck, Mike

Coach Rich

Danielle, sorry, I don't know anything about Stages PMs. I'm moving this from Macro to the Power Forum, where more people will see it.

GMAN 19030

Danielle, did your 910 work well with your Stages prior to the update? If so, you're one of the lucky few. There's a known issue with Stages and the 910 in which the 910 has trouble picking up and holding the Stages signal.

Doesn't sound like the same issue you're having though.

Danielle Santucci

Thanks Mike, yes I finally got it to recalibrate around 908. When I initially recalibrated with my Garmin, I was moving. After speaking with a fellow triathlete at the gym he told me to make sure my pedal was at the 6 o'clock position and not to move it until the recalibration was complete. Did it and now it works the way it should . Hopefully this will be the last issue.

@Bob...hopefully this doesn't happen during a race. Need that data ))

Kiwinoz

It is best to fix a 910xt to your bike if you are using a Stages PM, it will routinely drop out from your wrist.