Garmin 910 multisport question
I raced Quassy yesterday. This was my first race that I used both my Garmin 910 with my new Garmin 500 together. I have my 500 mounted on the bike and I wore the 910 on my wrist. I calibrated both prior to race start in transition area. Then I switched the 910 to multisport mode and went down to the water to begin. I went through the race using both, but really just staring at my 500 on the bike and not paying attention to my 910 until my run.
Here's my question. I went to upload my data from the 910 last night and realized that it did not pick up any power numbers from my bike. The 500 did. Once you are multisport mode on the 910, is there a reason I would've lost the connection to my powermeter? This is good info to have prior to the next race. Thanks!
Here's my question. I went to upload my data from the 910 last night and realized that it did not pick up any power numbers from my bike. The 500 did. Once you are multisport mode on the 910, is there a reason I would've lost the connection to my powermeter? This is good info to have prior to the next race. Thanks!
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Brad, I used my 910xt and Edge 810 yesterday as well. Mostly because the 810 provides me more info and tends to have better and more accurate power numbers to the 910. I have had standing issues with the 910 dropping power values while I still have power values on the 810. Although I've had the other situation where the 810 drops to zero power and the 910 is displaying positive power values.
On average I feel and have read online that the 910 looses signal more often than other power units, although I've only used power on the 910 and 810.
One standing issue I do have with my power meter (an SRM) is with magnet alignment to hit the cadence leaf in the power meter. Yesterday I had to stop four times to fiddle with the magnet to change the alignment because the power dropped out and I was getting zeros on both units. After the fourth attempt the power numbers stayed and I didn't have a problem with it for the rest of the race.
Ideally I need to come up with some solution other than the cheap plastic magnet holder to hold the cadence magnet so it doesn't easily move around. I know Quarqs have a pretty nice magnet ring which is held on by the bottom bracket and will not move. There has to be a better solution to be able to adjust the magnet and enable it to stay put without having it move around from ride to ride.
From slowtwitch :
http://tinyurl.com/mol2445
http://tinyurl.com/n5nuz4b
Actually, correction on the above. I've also read some have had their power meter serviced by the manufacturer to increase the signal strength with some success. The only draw back to this solution is that with the increase in signal strength you also get a decrease in battery life. For me with an SRM, I have to ship my crank to Utah to have them replace the battery. With Quarqs and PowerTaps it is an easy battery change.
Which PM? If it's a Stages PM it's a known (and unresolved) issue with the 910.
@Trish, here are the instructions to calibrate a Edge 500.
https://support.garmin.com/support/searchSupport/case.faces?caseId={4232ebf0-9dc0-11e0-d01c-000000000000}
Sorry, very techy answer but this is the simplest why I can explain it. Someone might be able to give a better answer.
Calibration is important just like having atomic clocks to keep global time, or having standards of measurements to ensure an inch is an inch and a yard is a yard. If there isn't a standard you can compare against you don't know if the values you are looking at are accurate or not.
There are two types of calibration. There first is the calibration of your bike computer to the power meter to adjust for environmental conditions (mostly temperature) because metals expand and contract at different rates depending on the change in temperature and thus give off different readings (voltages) which can impact what you see on the bike computer. The calibration of the bike computer eliminates (or at least mostly eliminates this drift in the calibration value) between calibrations and day to day use. The second kind of calibration is against a global standard to ensure that 1 watt on your power meter is equal to or at least as close as possible to 1 watt on a global standard or 1 watt on a different properly calibrated power meter too that same standard.
If your bike computer is not calibrated regularly to your power meter, you could be putting out 100 watts of power when you are actually really putting out 150 watts of power (or vice versa). Calibration ensure that the number you are seeing on the bike computer is actually what your power meter is reading. If you swapped out your power meter it is particularly important to re-calibrate because the the baseline values of the new power meter may be completely different from the previous one.
On a side note, there are some bike computers that will calibrate to your power meter automatically. You will need to read the bike computer and power meter documentation to see if you have this feature.
@Brad, Two things to try.
Go into Bike Settings > select your bike > Bike Details > ANT+ Power > Sensor Details to see if the Sensor Id field is populated.
The other place to look is to see if the calibration value is zero instead of a reasonable number. If there is no calibration value (or it reads zero) you won't have any power. I've had the calibration value drop to zero for no apparent reason a couple times and had to stop my ride to re-calibrate my PM after which is was fine.
Brad, I used my 910XT and Garmin 510 on my Race on Sunday. And both worked fine.I turn on the 910XT in Bike Mode so I can calibrate it to the PM (and make sure the PM and 910XT are connected). I then change the 910 to Multisport mode and run the race ...you have to press the lap button at the appropriate time so that when you are on the bike, the 910 is in Bike Mode.
it sounds like you never put the 910 in Bike mode.
Sure wish someone (my old coach, who sold me the power tap perhaps?) would have clued me in to calibration! I hate that nothing comes with a paper manual anymore. I just don't read them online! Gah!
Thanks Darren. See you in IMMT...I'll be the confused tech averse one.
@Brad - Good plan. Nothing worse than having uncertainty when you are racing.
@Trish You don't need always to know the "why or how" behind the things we do ... but sometimes it helps to motivate you to do them. In the case of Calibration here is the short "Why":Power = Torque x RPM. So power is a calculated value and not measured directly. The PM uses strain gauges to determine torque (how hard you push the peddles). Calibration is done at a no-load situation (zero torque) time. This is what calibrating our PM means. We need to calibrate the strain gauges every time we ride (and should do so periodically during rides as well by back peddling 5 times - per the manual
) because strain gauges are sensitive enough to be affected by changes in temperature.