Help! Can't figure out Powertap G3 hub calibration with my Garmin 500

I hope someone has run into this. I’m test driving a Powertap G3 wheel to buy from a friend, and can’t get my Garmin 500 to calibrate it. It recognizes the power meter, but when I select calibrate, it just stays on that screen, forever. I never get the “Calibration Successful” notification. For anyone with this computer / power meter combo, what is supposed to happen? I have the settings also checked to Auto Zero. I’m really not sure what I’m doing here (I guess that part is obvious though). Power newbie would appreciate any help. Thanks.

I dont a have a Garmin 500, but use my G3 with a 910XT. When I spin the wheel the Garmin pops up a message asking if I want to calibrate. I select yes and then get the calibration successful. The Torque value should be zero and the calibration value will either be 512 +/- 20 or 0 +/- 20. This depends on the firmware on the hub. Newest firmware gives a 0 calibration value.

The autozero function does this calibration when you are coasting. If that is set you don’t really need to do the calibration step above. However, if that isn’t working then I would wonder if the units are communicating properly.

Do you get any power figures when you pedal, and does it go to 0 when you stop?

Do you have HRM configured? This thread here suggests that might be the problem if you are not wearing the HRM:

https://forums.garmin.com/showthread.php?94866-Edge-500-won-t-calibrate-with-PowerTap-G3

Had this problem with a 500 and G3: try disabling all other devices (hr/speed sensor etc) first.
Then add powermeter and calibrate, then re-enable other devices.

Try backing out of the calibration screen when it hangs, spin the crank backwards one revolution, then go back into the calibration screen and try again.

Had this problem with a 500 and G3: try disabling all other devices (hr/speed sensor etc) first.
Then add powermeter and calibrate, then re-enable other devices.

This is the right answer. If you have a speed/cadence sensor enabled on the Garmin, make sure you have one on the bike and it is awake, if you don’t disable it. Same goes for a HR monitor, if you have it enabled then have it active, otherwise disable it.

Had this problem with a 500 and G3: try disabling all other devices (hr/speed sensor etc) first.
Then add powermeter and calibrate, then re-enable other devices.

This is the right answer. If you have a speed/cadence sensor enabled on the Garmin, make sure you have one on the bike and it is awake, if you don’t disable it. Same goes for a HR monitor, if you have it enabled then have it active, otherwise disable it.

On a bike with a G3, you don’t need a speed or cadence sensor since they are both broadcasted (along with power) from the G3.

Perhaps that’s an issue.

I’ve been trying all of those, but still no go…

That’s all I’ve got, it’s a known issue with the 500 though.

Know anyone else with a Garmin that can try?

I’ve been trying all of those, but still no go…

i think when i did it (couple of years ago now) it was a right faff.

i think i completely removed each sensor from the garmin in the setup (i had HR and speed/cadence), then set up the G3 hub, then added the other sensors back on again.

i seem to recall it was a right pain in the ar*e but it did work eventually.

as someone else has said it is a known issue with the 500 - i think there’s a firmware update which was meant to fix this so might be worth checking to see if the garmin is up to date.

I have a G3 paired with a 500.

Don’t need speed or cadence sensor at all, it’s built into the G3 hub.

After you find the G3 with the 500, turn it off and then back on again. The 500 will then hold the sensors for the bike selected in memory.

The OP never replied to the question iwaters asked:

"Do you get any power figures when you pedal, and does it go to 0 when you stop? "

This happens to me if the heart rate setting is “on” but I don’t have my heart rate monitor on yet.

I have a G3 and a 500 and, like you, no other sensors besides my HR. I have had issues where it would stay on the “calibrating…” screen for a long time but then I turned it off and back on and it seemed to work again. I probably had an issue before and just did either a soft reset or turned off all the devices then had the garmin re-find them.

.

Unpair your HR, or wear it when calibrating.

I’ve tried both, but unfortunately with no success.

Sorry about that, answering from a smart phone so I’ve missed some comments. Yes, it reads power, and it is at zero when not pedaling. Did a Zwift ride last night to test it. Just thought you were supposed to calibrate no matter what. I had no other sensors on the unit except for an HRM. I have a G3 paired with a 500.

Don’t need speed or cadence sensor at all, it’s built into the G3 hub.

After you find the G3 with the 500, turn it off and then back on again. The 500 will then hold the sensors for the bike selected in memory.

The OP never replied to the question iwaters asked:

"Do you get any power figures when you pedal, and does it go to 0 when you stop? "

Whoa!!! I may have missed this! I use this head unit on two bikes, and one bike does have a hub based speed sensor. TOTALLY forgot about that one! My bad, I’ll try that tonight! Thanks!

While the GS has cadence and speed built in, there’s no reason you can’t use an external sensor. I have a Giant with the “built in” speed/cadence sensor which I prefer to use over the PT one since it actually measures cadence vs estimating it.

Good call on checking the multiple bike settings. I use my 500 on multiple bikes, one with a PT and speed/cadence sensor, another with a Stages and no other sensors. Works fine other than the 500 requires going 473 menu pages deep to change bikes.

It was the speed sensor! Calibration success!!! Thanks Slowtwitch crowdsourcing!!!

Great! It’s such a stupid bug, I wish they would have fixed it.