Login required to started new threads

Login required to post replies

Indoor trainer power source setup..
Quote | Reply
I bought new direct drive trainer (tacx flux), so now when using Zwift, I have an option to use either power meter as power source or actual trainer.. I have tried both setups but both cons and pros

1) actually trainer as power source.
pro: during intervals power line is 10 times smoother
con: actual numbers are 10-15% higher than outside while i read most people have them lower in indoors vs outdoors

2) use power meter (4iii left crank) as cadence and power reading source
pro: same instrument measures power indoor and outdoor so power profile looks similar
con: during intervals lets say 10 min one, actual power readings are all over the place (10 min @ 200w i have seen 175 and 225 pretty often on 3sec avg) with the same cadence +-2rpm... I would think it is not that big deal during 10mins but if I do 3min @ 110% 3 min @95% 3 times there is not much difference between 110 and 95

It feels like trainer is trying to catch every second. I am not not sure if it is the problem of Bluetooth signal processing. read->send to laptop (Zwift)->send info to trainer-> trainer corrects resistance->repeat

Has anybody "played with this"? which setup would you use?
Quote Reply
Re: Indoor trainer power source setup.. [SBR.NYC] [ In reply to ]
Quote | Reply
The basic problem is you've got two somewhat unreliable power sources. The one-sided pedal is only providing half the picture and the accuracy of the tacx is difficult to verify.

Regardless of which one you choose, the actual power will not be 'smooth'. If the trainer is selected as the source it's just transmitting the target power not the actual power. You can verify this by selecting trainer as your source in zwift and recording your pedal power separately with a different head unit. Actual power is never steady in the short term, particularly if it's being recorded once per second. If you want the display to look smoother you'll need to apply some averaging.

Better to just ignore the stochastic nature of power and make sure your interval averages are close to you target. The short term fluctuations are meaningless.
Quote Reply
Re: Indoor trainer power source setup.. [SBR.NYC] [ In reply to ]
Quote | Reply
SBR.NYC wrote:
I bought new direct drive trainer (tacx flux), so now when using Zwift, I have an option to use either power meter as power source or actual trainer.. I have tried both setups but both cons and pros

1) actually trainer as power source.
pro: during intervals power line is 10 times smoother
con: actual numbers are 10-15% higher than outside while i read most people have them lower in indoors vs outdoors

2) use power meter (4iii left crank) as cadence and power reading source
pro: same instrument measures power indoor and outdoor so power profile looks similar
con: during intervals lets say 10 min one, actual power readings are all over the place (10 min @ 200w i have seen 175 and 225 pretty often on 3sec avg) with the same cadence +-2rpm... I would think it is not that big deal during 10mins but if I do 3min @ 110% 3 min @95% 3 times there is not much difference between 110 and 95

It feels like trainer is trying to catch every second. I am not not sure if it is the problem of Bluetooth signal processing. read->send to laptop (Zwift)->send info to trainer-> trainer corrects resistance->repeat

Has anybody "played with this"? which setup would you use?

I have this same issue with my flux s but I’m using it as my control as it’s currently my only power source so I have nothing other than fee to go with.

I started Zwift last week but the power is noticeably different between the two even after calibrating through Zwift.

I’ve had trouble trying to figure out how to calibrate a spin down in the Tacx app once an activity started in swift.
Quote Reply