Tool for power meter differential?

Hey all - when you are trying to track the difference between two power meters after a ride, is there a piece of software that analyzes the difference and let’s you know what the +/- adjustments you should make are?

In this case, I have been training to power all summer using my Favero Assioma pedals and my Kickr.

However tomorrow I’m going to be training outside on my gravel bike which has a left-side-only crank based meter. I’m doing an endurance ride with the gravel bike on the Kickr today and am going to capture both values, but unsure how to gauge the differential. Do you all just eyeball it?

Any tips are appreciated. Thanks!

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This is one of the most used options. Not free, but very effective:


Which single sided power meter are you using?

Pioneer for Ultegra

Don’t bother, seriously. Eye ball if needed, I find the indoor/outdoor gap bigger than smart-trainer / powermeter gap.

I would suggest putting the Assioma’s on the gravel bike, and capture power from those and the Pioneer. This way you can directly compare the left values, otherwise you will be comparing left only to L/R, which will add some confounding variables to the comparison. I’ve also found my kickr to be quite variable in the power it reports, but I have no idea if my experience is typical or unusual. I’ve had my kickr vary from about +5% to -5% within a single ride, so it’s not a good reference for me to use to compare power meters.

I’m trying to align my Assioma single sided power meter with my Stac Halcyon at the moment and finded that to get actual precision is deeply frustrating. It appears that I have L/R inbalance that reduces as a) I fatigue and b) as the wattage increases. I therefore get different deltas for sweet spot, endurance and VO2max workouts. Also irrespective of the type it changes as the workout progresses. I’m still thinking about what to do about it. The OCD side of me says I should a different adjustment factor into the Stac depending on the type of workout I intend doing whereas the the more rational side of me says just pick a figure somewhere in the middle.

I’ve been asking for this for years.

Sure you can use the DCR tool, but a single app that can dual or triple record would be so simple. No matching start times or syncing intervals. Just start the module and record some 30:30 or something. Seems simple

I’d like to reach out and say is pretty decent and free. However it’s important to set times correctly yourself because there is no adjusting in the webapp.

For the differential I’ve measured it down to 1-2W difference between my Neo and my Assiomas but it took about 3-5 rides and I took like 15 measurements from each to calculate an average difference and when I had done that I set the scaling on my Assiomas to that number and re-tested. So quite a bit of trial and error.

My Direto and 4iiii left side crank had a difference of about 5% according to the average power of the ride, so I just modified the crank’s scale factor to 1.05 and now the post-ride average power is the same for both of them, which is good enough for me.

It seems like it shouldn’t be that hard for TR to record the data from more than one source, and be able to display those in the DCR tool. My guess is that this won’t happen because a) the number of people interested in this is fairly small, and b) it would likely generate lots of support requests since it is a complex feature to use.
Too bad really, as I expect if more people actually looked at their data we would find that power meters and smart trainers aren’t as accurate as we’d like to believe they are.
If nothing else TR should be recording this data for their own use - this would give them a lot of insight into how power meters and smart trainers really correlate in practice. This data is available for them to record for anyone using powermatch.

There are is ipWatts and ipsensor free for android that can connect and record multiple power meters, but then you have to do little excel magic to chart and analyze.