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Power measurement

Posted: Sat Feb 02, 2019 8:15 pm
by danga
Hi All,

New to the forum so thanks for having me.

I’ve been doing some power comparisons between my Powertap P1 dual side pedals & the Direto. So far what I’ve noted is a consistent difference in average and normalised power of roughly 15w which equates to ~8-10% where the Direto reads higher.

I’ve been in contact with support which has proved to be somewhat helpful to a point & after an adjustment to tension to bring the offset back within 5 (Factory-6279 vs current-6274). Support are now questioning whether the pedals are correct in terms of there measurement after a number of .fit files were sent for analysis, this is a fair question.

I was wondering if anyone could comment on Elites procedure in validating power numbers as part of quality control prior to shipment?

At this point I’m waiting for answers from Elite, but have to admit I’m a little disappointed in the difference in power and would like to get to the bottom of which may causing me the different, could be both really. My money is on the trainer just based on other forums and reviews of users having the same issue as me, however I have no scientific fact to suggest it’s the trainer and not the pedals.

Dave

Re: Power measurement

Posted: Mon Mar 11, 2019 4:18 pm
by ian_thompson_
Did you ever get an answer from this? I am also finding that my P1s are reading 10-15 watts lower than my direto... would be interested in any update?

Re: Power measurement

Posted: Tue Mar 12, 2019 8:48 am
by danga
A few things have happened since then, but in short:
- belt tore
- replaced belt and calibrated to within 2 points of factory offset
- tested against Powertap P1 & Favero Assioma dual sided pedals and both show ~10% lower power readings than the direto
- Elite Italy have agreed on a replacement unit, I have have sent data to Elite Australia and am awaiting a response for a replacement unit.

NB: after 4-5 hours of using the unit the calibration has dropped another 2 points, so it is now 4 points off from the factory offset. That’s quite a drop for minimal use, but perhaps the bew belt and pulley are bedding in and this will stabilise.

It’s also worth mentioning that those who’ve had differences in power readings have been able to bring the back with then calibration procedure. I’ve not been able to achieve this, and my power difference is always around 10% and not a constant power reading differential (eg. 20w)