Left/Right Balance Confusion


I have recently noticed that on Trainingpeaks, the Left/Right power balance seems to be flipped.

I’m recording data on a 4iiii, left side power crank. So, I would have thought that the data should be 100%/0%. However, it seems to be the other way round.

Is there a simple explanation to this which I am missing?



It’s probably just written as right/left, and not left/right. The writing order doesn’t have to represent the way things are mounted on the bike.

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That does appear like it would be the obvious answer. Although, it still seems like an odd choice. Seeing as I’ve always heard it expressed as Left/Right power balance, it’s unusual that Trainingpeaks would have decided to display it as Right/Left.

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I also have a 4iiii left side PM. When I look at the power recorded with the Wahoo Bolt it also says 100% right. Nothing to be worried about, it’s just a bit strange.

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I also have a 4iiii left side PM and according to my last TP ride I’m 0.11%left sided/ 99.9% right sided :thinking: :joy:

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I’m always 80/20. Good to know there’s an extra 20% that I’m somehow not getting out of my left leg :joy:


All very interesting! So, is everyone saying that the left/right ‘flip’ is coming from the 4iiii? For instance, if I was to use a pair of Assioma Duo pedals, would trainingpeaks display power balance as Left/Right, in that order?

No. TP have just formatted the field so that it shows right/left power. Probably because we tend to write from right to left, and saying right first is normal.

L/R power balance is displayed as Left/Right across most if not all platforms, by convention. In the background the balance values are between 0 and 1, where 0 = 100/0, 1 = 0/100. I know this is the case for TP, and I don’t think any other platform is swapping that order.

I have dual- and left-only 4iiii power meters. And yeah, the left-only shows 0/100 for some reason. Maybe it just defaults to sending a ‘1’ when only one side is present? Maybe it’s related to pedal smoothness or torque effectiveness, or some other correction factor, which could explain why it’s not always == 0/100?

Other L-only power meters don’t show any balance values at all. So I believe it’s something on 4iiii’s end. Either way, it’s meaningless. As far as I’m aware, you will always end up with a flat 2x the power number measured on the left side.


That is not true. Here is a day when left side battery died during a 3 hour ride:

And Garmin:

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TP is definitely formatted Left/Right. I have Assioma Duos and the TP data matches Garmin Connect data.

When I ride on Zwift, which is recording power from my Kickr (I.e. no L/R balance data) TP does not show a L/R breakdown at all. It’s not just blank, there is no balance field displayed for those rides.

So, whatever is showing up in TP is coming from the power meter.

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You tend to write from right to left?

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To complicate it further; my Favero Be Pro S (single sided) doesn’t give me any balance in TP just the single sided 4iiii.

(The Be Pro S does give a power balance in GC however (or what Garmin call a Torque Effectiveness anyway), its usually 90R/0L for me :exploding_head:)

Torque effectiveness is different from power balance


Ummm…the other right and the other left! :joy:

Yeah, I just tried to find out how it looks for me, but I don’t have a power balance field on TP with a single-sided PM.

So if it’s not a case of simple formatting, maybe the PM is paired as a dual sided PM, despite only being single sided, and the right side would get paired first?