Tacx flux smart wattage problem?

Hello there,

Lately, like a couple of weeks ago, I have the impression that I encounter problems with the tacx flux smart on zwift.

To explain the case: today I decided to climb the alpe du zwift on Z3/4 (around 230 watts for a 260w ftp) but I wanted to make it more true, pedaling at around 75rpm.
I did the whole climbing at 230 watts average.
When I used to feel exhausted in the past, here I felt fresh enough to do it one more time.
So it appeared strange to me as the legs were really good (I did nothing this week btw), so during the descent i’ve recalibrated the trainer IN zwift AND thru the Tacx app. All went ok.
I climbed it a second time: absolutely no changes, all the same.
Once at the top, I was feeling good too. Legs a little bit tired, but still, around 2000m D+ I should feel uncomfortable.
My cardio during the climbs is turning around 160bpm, which seems quite low to me.

Do you guys also have troubles lately with the trainer or something?
Do you suggest me to do to understand if my trainer has a problem or not, or if I just got better ?

I am very confused because outside I used a 4iiii powermeter and I don’t think I have ever reached 230watts on 56 minutes, 2 times.
So I thought, maybe, I have less power in the left leg, but it doesn’t look pertinent.

I don’t know, I don’t know what to think about it…

Thanks in advance :slight_smile:

If you’re calibrating your trainer in the Tacx app then there’s no need to calibrate it in Zwift as well. In fact, I’d recommend just using the Tacx calibration since the manufacturer apps tend to do a great job at it. Since you have a power meter already, the best thing to do next would be to do a test ride on Zwift while recording the data from your power meter on a second device and comparing the ride data. Ideally the test ride would be long enough for the trainer to warm up and include a few short sprints and some tempo riding

The ZwiftPower Analysis tool is a great way to compare the fit files for a dual recording analysis as it puts both power graphs on the same timeline so you can easily see how close they match up. Just create a New Data Set then select the activity from the “Use fit file from Zwift Activity” and upload the file you recorded on your other device from the “File 1” upload field below and click “Create Data Set”. From there you should pretty much be able to see at a glance how accurate your trainer is, but you can still adjust the start offsets to make the graphs line up better if you want a second by second comparison

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Hi, i suggest you do a zwiftpower.com dual recording… read this How To Use ZwiftPower’s Dual Recording Power Analysis Tool | Zwift Insider

What i believe is that your trainer is overestimating watts on climbs and it will most likely be the other way around on the flats…try to do a 230W effort on Tempus Fugit and you will most likely notice that it’s much harder.

If you look the power on your Bike Computer from 4iii you can also compare that to Zwift.