Difference in Left Right Balance

Just got back from a ride and noticed that my L/R balance in Intervals was 60/40. Checking on Garmin Connect shows it at 57/43. Something slightly off somewhereScreenshot 2021-04-12 at 14.46.39

Hmm. It seems the Garmin analysis is ignoring zeros for L/R balance. Intervals.icu keeps them in. If you are only pedalling with your left leg then you should get 0 and only right leg 100 (and there are 100’s in the data as well). So I think it is better to keep them?

You can click “Ride CSV” here to look at the L/R balance data: https://intervals.icu/activities/i889450/data

Thanks David. That link to the CSV table is brilliant. Ive got a significant left right imbalance which I’ve thought evens out the harder I go. That table seems to confirm it. It’s plays havoc with my data when I use a single sided PM on one of my bikes

I have noticed that my L/R balance in intervals.icu is systematically the opposite of the L/R balance given by Training peaks although it is always around 50/50. For example, it is 49/51 in intervals.icu and 51/49 in TPs. At this point I have doubts about which is the left and which is the right…

I have had some problems with this in the past but with 49/51 its not easy to know which is correct.

The LR data can be found within the original FIT file.
The decoding goes something like this…

The payload[2] basically checks if the PM is a LR or just a L.

		// LR Pedal Power Balance
			if ( payload[2]>>7  == 1 ) {
				_data.rPwrBal = value;
				_data.lPwrBal = 100-value;
			} else {
				_data.lPwrBal = value;           // this essentially becomes 100%
				_data.rPwrBal = 100-value;  // this is meaningless. WHich means redundant code for me
			}

Tx. Where did those docs come from? I have figured this out just from looking at the data.

It’s from the ANT+ specs.
There’s also Bluetooth Specs for Power Meter etc. (I abhor reading the bluetooth specs. It’s full of holes and the language makes my head spin)

Took me a while to figure out how to deciper Bluetooth Power Meter numbers for the BreakAway Indoor Training App when I don’t have a Trainer That talks FTMS

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