The Ergomo doesn't care what size or shape rings you have. The measurements are taken within the bottom bracket and gearing does not matter.

Neither does The Sergio.

thanks. he just called me back and said it would work, but the issue now is getting the right width spindle to work with the P3C . . .he knows what he needs but won't be ready in time for this weekend's ride. . .arrrgh.

"The Ergomo doesn't care what size or shape rings you have. The measurements are taken within the bottom bracket and gearing does not matter."


While you might think so, this may well not be the case. There is a reasonable amount of evidence to suggest that non-round chainrings may skew PM readings on some powermeters, although I haven't heard whether this is the case with the Ergomo.

There was a thread on BTR a while back on PM accuracy with Os and Rotor chainrings, and how they could skew SRM readings. It's worth checking out, or perhaps Jens will chime in on the topic here...



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Without doing all the necessary research, it would have to do with the sampling rate. If you do enough samples you'll get a number that is repeatable if not 100.00% accurate.

Maybe.

It could also be a combination of sample rate, and strain gauge alignment/force vector, which is really kind of a sample rate issue, or maybe sample type is a better description. Either way; increased non-linearity of power output with non-round chainrings can skew wattage readings, and this is more likely to occur with increasing assymetry of rings, and limited sample size/type capture.



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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

doesn't really matter how accurate it is. If it spits out a #, and looks like cool technology, I want it. 85% of this sport is having cool looking stuff, right?

It's funny you are commenting on how assymetrical rings might fool a powermeter. I started a thread which I asked if anyone had seen similar results. It was surprisingly *QUIET* and I got no response on the subject from Gary.

http://forum.slowtwitch.com/...earch_string;#950523

I really believe that the wattage on my ergomo went up in relation to speed (indicating some sort of tom-foolery with the measurement of power). I will say that I do believe that Q-Rings are beneficial and have improved my speeds. I would recommend them for sure. Who knows? - Ernie

I'm with you. I have an Ergomo (sport, going on 18 months now) that I love.

Yes, Q-Rings are compatible with Ergomo.

I've got the setup, Ergomo, Q-rings, P3C. Works great.

-C

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Any run that doesn't include pooping in someone's front yard is a win.

what cranks, spindle do you have on there?

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under-trained and over-tapered. . . .yet still hopeful . . . does that make me an optimist or a masochist?

I've got the zipp cranks. What do you mean by spindle? I'm using the ergomo pro.

-C

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Any run that doesn't include pooping in someone's front yard is a win.