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Difference between Smart Watch Venu 3S and Indoor Trainer Smart Flow

Nguruh
15 days ago

Hello

I have a Venu 3S and a Tacx Smart Flow indoor Cycling trainer. I started a free training session with Tacx and started indoor cycling on the Venu 3S (which is also connected to the Smart Flow via Bluetooth).

However, I have now noticed some significant discrepancies:


Venu 3S:
1 hour of training
25.2 km/h average speed
25.17 km distance
135 watts average power

TacX App
1 hour 1 min of training (I started 1 min later on the watch)
28.9 km/h average speed
29.54 km distance
134 watts average power

Which data is more accurate? Why are there such large differences with these devices? I assume the Smart Flow Bluetooth sensor should actually send the same data to the watch and the TacX app?

I now also have two indoor training sessions on the Connect app—I assume I can't synchronize these?

Thank you for your help.

  • 0 9 days ago

    My guess is they have different wheel size setup.

  • 0 9 days ago

    because coming from 2 different calculation methods: 

    Venu: speed is coming from the trainer's speed sensor data (so the physical speed of your rear wheel)

    Tacx app: speed is calculated virtually from the reported power with the other variables.

    these 2 never will match (it is similar if You use Zwift or MyWhoosh and not Tacx app), delete what is not sympathetic

  • 0 9 days ago in reply to Luko79

    So because of the physical speed of the rear wheel, the Venu should be more accurate? Or less accurate, because i cant configurate the wheelsize?

    Why dont TacX (or Zwift etc) use the phsysical rear data and calculate with some variables? Shouldn't the physical impact with the right wheel-Size be the exact one? (like the old-school trackers on bikes)?

  • 0 6 days ago in reply to Nguruh

    there is no accuracy (or telling this is more accurate than the other) indoor in distance. the duration is the most important, and the power (unfortunately that is not accurate with Flow, but it is an another story). as i said, choose what is more sympathetic, thats all.  for your 2nd question: in virtual world the power is the key, nothing more. You can pedal in ERG mode with constant rear wheel speed, but the power can be 100w , 200w, 300w or any other value for mins or hours. this speed sensor feature is coming from old days where there was no such an app like Tacx or Zwift or MyWhoosh, and there wasnt ERG mode neither in the trainers. honestly the best would be Tacx will remove this thing or somehow make a bridging from these apps that the ingame speed should transmit to the head units via this speed sensor data (and in this case the 2 distances would be equal) btw lots of people is not using head units indoor (to avoid such a duplications), just the Tacx or Zwift (these have integration into Garmin ecosytem for sure)