WARNING: Garmin Auto-Zero function
If you are using a track powertap with a Garmin, DO NOT UPGRADE TO THE LATEST FIRMWARE (2.7 on my Edge 800)... They have removed the ability to disable Auto-Zero.
It doesn't mention that it has been removed in the update notes, and you CANNOT downgrade.
its been a while since i used a powertap on the track- and it was one of the old yellow wired units... i do remember turning off the Auto Zero..
does not being able to kill the Auto-Zero make that head unit unusable? i was under the impression that the auto zero on a PowerTap only actually happened when the wheel was spinning but the cranks were not(ie Coasting)? and thought it needed 5sec to complete.. since you can never do that on a track bike... does it ever actually attempt to auto-zero?
There have apparently been quite a few issues with the powertap doing an auto zero while the rider is stopped but not pedalling (ie. in the starting blocks)... as the rider can have a significant amount of force on the pedals (and hub), the readings after are out.
I have just been told that turning auto-zero off fixes these erroneous readings.
I rang Garmin and after they gave me the bad news, I had some stern word with the supervisor... anyways, they are going to send me a new edge 800 with the previous firmware in exchange for mine.
I know that the road/tri crowd are their bread and butter. But, I wonder how much effort it would take for them to create a "Track Only" firmware update.
- Keep it clean and simple
- Remove auto-zero
- Increase the sampling rate options
- Disable GPS mapping (you'll only get ovals on the map anyway)
- Disable GPS speedometer (disable GPS altogether)
- Strip out a lot of the other road/tri-specific features
I know it's a long shot, but something like a tweaked Garmin 500 could be awesome for track.
This would be awesome!!!!
Originally Posted by carleton
I end up letting the GPS lock in its signal- then quickly start and stop recording the activity- then turn off the GPS. That gives me a map of where I am and let's Strava know its not a Trainer ride...
Also- Bontrager was the only ant+ front wheel speed sensor I could find. I find front to be way easier at the track.. And my crank has cadence..
Picking up a wireless Little Yellow Computer (powertap computer) off of ebay can be fairly cheap and allows disabling the autozero and still records at 1 second with no gps. It is good to have if you ever want to verify torque settings on the hub. The viewing of the saved data is not as nice and it only has the concept of a single file in memory at a time.
Garmin took the autozero option off the 500 a while ago and usually the values are the same on the garmin and lyc, but sometimes the autozero kicks in when slowing down after an effort usually followed by death trying to hold the power for the next interval.
From the anecdotal comments near as I can tell they aren't all that helpful to their bread and butter crowd for customer service.
Originally Posted by carleton
Wondering if a Joule would work (vs. buying an old PT head unit).
I actually have a Cycleops Cervo 2.4 computer for the hub, but I don't have any of the accessories.
Originally Posted by slindell
To use it effectively, I would need to buy the HR strap (it's not ANT+), speed sensor, cadence sensor, mount and USB data cable... it was just going to be cheaper to buy a whole unit again with all the bits.