Elite Justo 2 sudden power overestimate

Equipment
1

Hi,

I will try to explain this as concise as possible.

The other day I was doing a 60min TR workout. It was endurance made mainly of 6-7 min intervals at 180-190W.

I have an Elite Justo 2 connected to my ipad via bluetooth. On that day I was not using an external cadence sensor because it was on the other bike. So cadence is reported directly via the Justo 2 (which I understand it is not measured but estimated via algorithm).

ERG mode was off.

At some point around min 46 the measured power became way higher than expected. It was in the range of 230-250W while my effort was still in the same zone 2.

On that day I was double recording with my Assioma DUO pedals connected to my Garmin so I was able to compare the traces.

I am attaching a screenshot of the activities comparison for the whole 60 min and also a zoom to min 46-56 where it is very clear that the two traces are diverging.

I don’t recall anything special I did before this happened. It could be that I changed the front chain ring from large to small, but I am not sure.

I remember that I kept going at same effort and on the Garmin I saw the expected 180-190W range and on the TR app I saw 230-250W.

I contacted Elite asking for their assessment, and they were completely useless. But that no surprise. The worst customer service ever…

Anyone has a clue of what happened?

Thank you!

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2

It looks like you’re getting cadence spikes, which could be inflating your power..

You shouldn’t need an external cadence sensor for either of your power meters to function properly.

I wonder if some data from your pedals was starting to interfere with your trainer…

EDIT: Actually, it looks like cadence spikes was an issue with this trainer in the past. Could you try updating your firmware?

3

The Justo 2 has internal power meter and it is supposed to be very accurate. The cadence is reported via software calculation but it is not be used for power calculation (AFAIK).

My guess it that cadence spikes are affected by the power spikes and not viceversa because the smart trainer calculates cadence using power as input…at least this is my guess

The limitation of the cadence calculated by Elite is well know but I think it is a general limitation of smart trainers.

different story for pedals which can measure the cadence directly