Analysing power - Favero Left, Right & Kickr

So I have a Kickr Core and a Assioma Favero Duo Pedal set.

My Kickr Core recently gave me a FTP if 307 while the pedals gave me 286. When doing other workouts/races/rides (on TrainerRoad and Zwift) the power reading is consistently lower coming from the pedals.

I have ensured they are correctly calibrated and I’m aware of the power match option.

It seems weird that the Kickr is reading higher though (normally the other way around) so I used the DC Rainmaker power analysing tool, and it shows that my right pedal and Kickr are actually pretty close but the left pedal reads 5-20w less than the right & Kickr.

After finishing rides my left/right balance is always very similar 51/49, 48/52 etc.

I’m not quite sure what to make out of what the analyser tool has shown, if anything, so I thought I’d ask here?

It just seems weird that the right pedal and Kickr track closely but the left is lower. Could there be an issue with the left, or is the fact that the right and Kickr are close just a co-incidence and the left/right difference is ‘normal’ (My left leg being weaker) and I will need a 3rd power meter to really see if it’s the Kickr or pedals that are reading wrong (given the overall power reading is outside the 2% accuracy range? I have a stages on my mountain bike so I could put that bike on the trainer and use the Duo pedals, but given the Kickr is left only I wonder if this will be of any help in terms of accuracy?

Any thoughts?

You can check the static calibration of the Faveos fairly easily. Basically, you will need to hang a weight from each of the pedals. The exact weight doesn’t matter, but should be close to what they recommend (10kg I think? it’s been a while)
When doing the test in the app, it will give you a reading from the pedal. Do this on both sides - you can cancel out without making any changes after seeing the reading.
You want both pedals to read the same value when the same weight is used. If this differs by more than about 1% (my tolerance guess) then you should take this up with Favero support.
For instance, if the static weight reading is ~8% lower on your left pedal, then this could explain the difference. The static test is limited in what it can tell you, but it can identify some problems.

Having spent too much time tracking down power inconsistencies with my duos and kicker I feel you pain. I would see quite a bit of variability of my left/right balance on short time scales, like what you see in your second and third intervals, so I think that is ‘normal’
Also, start using the assioma app to zero offset your pedals. This sends telemetry back to Favero, so if you do need support they will have some data from your pedals.


Have you tried with different flywheel speed (long/short gears)?

I had a similar situation with my assioma duo and H2. It looks like that the trainer overestimates power at high flywheel speed.

The power was spot on if I used short gearing, and 5% off of I was using long gearing (same training, just changed gears during intervals).

This is a common/known issues among trainers that have a calibration curve (as I understood the curve doesn’t account for the effect of different flywheel speed). I might be wrong, and I am happy to learn more.

If you use power match doesn’t really matter.

How are you getting right only? The left is master and right by itself is useless. If the graph is a plot of left & right power then combine is your power output and your Wahoo is under reporting, by a lot. Anyways, you need a third source to find out which is true.

Your left right balance seems ok to me.

Just one thought. How sure are you that when you recorded your FTP test on your pedals that it was recording the full power and not just the left pedal doubled? With some Bluetooth settings the right pedal is ignored on some head units/programs.

For instance with trainerroad you need to select the “unified channel” setting.

This only effects Bluetooth - ant
should just work.

I’ve got a 5-10% difference with my Zumo turbo (Zumo being lower) depwendent on the gearing I use (and hence flywheel size). I don’t know whether this is a function of the flywheel speed, the normal differences of the 2 PM’s, drive train losses dependant on chain angle, whether ther is an R in the month or whatever. All I know is I got increasingly frustrated trying to figure and sort it out until I just accepted it. You could use the the power scaling factor on the Assiomas to try and match your Kikr so that you get as close as possible but you woud have to do a number of rides at different intensities and gearing to get a close average and even then I suspect you would get the occasional weird result. All the data points were done at 80 rpm, in Erg at the same power over 3
minute intervals I suspect that different cadences may yield even different results as I have a large L/R power imbalance which varies with cadence.
Power Variance AssDuo v Zumo