power2max versus powertap

A light bike doesn't replace good fitness.

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dierix
Posts: 28
Joined: Sun Jun 07, 2009 10:51 pm

by dierix

i have a power2max and was comparing it with my old powertap (pro). Difference is about 40 watts in favour of the powertap on my training course (speed/cadans/heart rate is nearly the same). Tried it a few times now and it is always between 30 and 40 watts.
Any ideas?

denzity
Posts: 96
Joined: Sun Mar 27, 2011 10:01 pm

by denzity

If it's always 40 watts it sounds like the intercept is wrong. Have you tried stopping pedalling for 2secs so it re-calibrates? How about calibrating from your garmin? Could also be the powertap that's off. I have both and ran them together once with a 5-10w difference during a TT.

dierix
Posts: 28
Joined: Sun Jun 07, 2009 10:51 pm

by dierix

thanks, will try that

Krull
Posts: 775
Joined: Thu Dec 18, 2003 1:16 pm
Location: muc

by Krull

denzity wrote:If it's always 40 watts it sounds like the intercept is wrong. Have you tried stopping pedalling for 2secs so it re-calibrates? How about calibrating from your garmin? Could also be the powertap that's off. I have both and ran them together once with a 5-10w difference during a TT.


i have both as well and ran them together on different intensity-levels: very close together, difference most of the time between 4-8 w. at around 200w it was a little bit more, ca 6-10w.

in the worst case, you have to send one of your systems to the manufactorer who has to recalibrate it.

there was a case similar like yours, concerning p2max, in german "tour-forum. the users powermeter showed to low numbers. he got it recalibrated by "saxonar", and it worked fine.
sorry vor mai bed englisch!

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