Day of IM powermeter question
These are likely dumb questions, but if someone could provide guidance I'd appreciate it. And for background info, I have a Quarq pm and garmin 510. On the day of the IM, I will calibrate in T1 in the early morning. Given the temperature changes from early morning to late morning and into afternoon, my question is then when do I need to recalibrate and how? Thanks!
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You don't need to recalibrate. I would be very surprised if anyone suggests recalibration is necessary...Calibrate...Go Swim...Get out and Ride...Done...End of Story.
Garmin should be punched in the face for incorrectly using the term calibration. Their "calibration" is just a zeroing procedure. Real calibration requires a fair bit of time, equipment and effort.
*End Rant*
To answer your specific question...
Do what Robin recommended - "calibrate" prior to the race, pedal backwards 5x at the beginning of the ride and again every hour or so. There is no button pushing involved. Pedaling backwards zeroes the Quarq. Pushing buttons (calibrating via the Garmin) during the ride will transmit some crazy power numbers as you would've zeroed while applying force to the powermeter. Do not do that!
I'm not trying to be difficult or purposely ignorant....but whats the purpose of doing this?....
I'm pretty sure I didn't see Pete Jacobs or Mario Vanhoeneker pedaling backwards/recalibrating as they were riding down the Queen K in Kona....idaknow...did I miss it?
I don't have a Quarq...so is it a Quarq thing?
Temperature changes of 20 degrees or more can cause the Quarq numbers to "drift" so the zeroing procedure eliminates that. The drift is still probably within normal margin of error but it does exist. It takes two seconds to pedal backwards 5x. No biggie if someone forgets but no biggie if they do it.
Did you watch all 112 miles of Pete and Marino riding to see whether they did that or not?
Is there ever an issue with the garmin picking-up other people's powermeter in the mass of bikes?
Yes there can be a problem with the Garmin attaching to the other bikes around.
Either don't worry about it and your powermeter will be found as you race or move away from the crowd with the bike to calibrate.
http://members.endurancenation.us/Forums/tabid/57/aft/11587/Default.aspx
Yes, you need to complete the auto calibration by pedaling back as described above. With temp changes over 6 hours from early morning, Quarq will drift, there is no question. And it will drift significantly too. Strain gauges are affected by temp changes.
You can verify this by conducting a 4-5hr ride, do manual calibration before start, go ride 5hrs from 6am-11am, than do another manual calibration at the end and take the readout of zero offset numbers. You will see a huge difference. Quarq site has some guidance on what kind of delta between the two calibrations may cause all the data to be invalid.
You sure don't want to overcook your IM bike ride, long way to walk. Part of mental prep of the race is rehearsing each task in a given time in your head.
Do you need it every hour, likely not, but you want it done at least a couple of times. Just my 2c. Been a powermeter user since late 2009. Take this for what is worth.
Just two more things, the more I read....
No need to push buttons, back pedal only. Read the note in big letters above.
It will be ok conducting the manual calibration in T1 with other bikes around as long as your device, garmin is not enabled to pair with others, do not use pair mode while you have any other ANT+ device but your own around, than it will jump around picking anybody. Too funny.
I have friends who ride with me and have no powermeter but have garmin devices. In order to subdue my ride they pair up quietly and than ask what effort/ power am I going to do this ride, than they go calling me out when I go over as they display my numbers.....took me time to figure that.