Tacx Neo 2T ERG vs. Resistance vs. Garmin Rally XC

Hello all! New to smart trainers (been at is about 2 months with TrainerRoad) and here is my question(s).

  1. I’ve been using EGR mode and during VO2 Max type workouts I have to spin at a cadence of 100+ to even hit my pathetically low power number of say 125. Save for the cadence the overall effort does not feel that hard and I know I have more power, but its like the trainer is not letting me apply it. Any thoughts? Trainer setup or rider?
  2. I have a Garmin 830 and Rally XC pedals with neither linked to TrainerRoad, yet. When trainer is in EGR mode the power numbers between the trainer and the Garmin components match almost exactly. Then with the trainer in resistance mode, even after reducing the percentage as far as possible I cannot get the trainer and Garmin power to match. There must be something I am missing in the trainer setup. Any thoughts?
    Thank you!
  1. I consider this required viewing for people new to ERG mode use.
  1. Is there a big difference in your gearing between the ERG and Resistance examples?
  • If you are in a high gear (big ring) for one and low gear (small ring) for the other, that’s a possible issue.

  • The Neo (and many other trainers) can diverge power data and show elevated values at higher gearing.

1 Like

Thank you! Very helpful video on ERG. Now to figure out why the Garmin pedals vs. Neo 2T power don’t align more closely in resistance mode…

  1. Per my question above, what general gearing are you using in Resistance mode?

  2. Are you calibrating the pedals as required?

  3. Some people report errant power data from Garmin pedals if they are not installed to the recommended torque settings. It could be worth a check if you just installed them without a torque wrench.

Those are decent starting points… but a word of caution. Discrepancies between power data devices is quite common and not always something that can be “resolved”. There are MANY topics in here with that exact problem, and not a solution in all cases.

Gear was small front (34T I think) and mid cassette 11-34. I’ll try running higher and see if power comes closer.

Yes, pedals were calibrated. Matched almost exact in ERG mode, just not in resistance mode.

I don’t have a 15mm cone wrench that does torque and the Garmins don’t have the hex on the spindle. If that was the issue I would think ERG would read off as well.

Maybe, but were you using nearly the same gearing in both ERG & RES modes? If not, the “speed” issue I mention could be at the root here.

Not enough data here to make any real claim other than something is potentially off. Any testing & evaluation needs to at least recognize the potential variables to start. And then totally control them to reduce influence to really get root cause analysis worth anything.

Also, are your Rally pedals single or dual sided? If single, that is a notable factor that must be recognized since the Neo is total power.

I’ve had two Tacx Neos and two sets of Garmin double sided pedals and this is my experience. The Neos read high relative to the Garmin pedals in easy gears (less virtual flywheel) on erg. They are very close to the Garmin pedals in harder gears (more virtual fly wheel) on erg. The difference is as much as 4%, pretty substantial.

TR’s power match is a great solution to this issue.


Pedals are double sided. Thanks for the advice. I’ll continue to scan threads in this forum and also experiment with various gearing and setups (ERG, resistance. and adding powermatch). Seems the best option would be to pair the pedals to the trainer (if allowed) and TR to trainer to always be using the power from the pedals.

  • That is not an option with the Neo’s AFAIK (but is with Wahoo for one example).

  • PowerMatch is the best solution if you are using the same bike & power meter inside and outside. Nullifies all the issues above.