Tacx Vortex Smart overshoots power at beginning of intervals

I’ve been training consistently with a Tacx Vortex Smart for the last year and I have always felt that the beginning of intervals felt significantly harder than the rest. I had always put this down to my body having to readjust to the increased work.

I have only very recently acquired a power meter in the form of a Garmin Vector 2S and - lo and behold - the power during the first 4/5 minutes is significantly higher than the target power reported by the trainer! (As can be seen in the graph, ignoring the lack of synchronisation due to Garmin and TrainerRoad dealing with pauses differently).
The power meter tracks 10/15 W higher, on average, during steady-state and that seems perfectly reasonable given the loss of power between pedals and wheel.

I should add that this is in ERG mode, as I never switch to Resistance mode. Is this normal? Is it something that other Vortex users are facing? Is it something that would happen with any trainer?

I have found that ERG mode just straight sucks with the cheaper wheel on Taxc trainers- have the same issue with the Flow smart. My ERG mode doesn’t adjust well at all- it doesn’t lower enough or quickly at all during rest periods, and spikes like hell at the start of intervals. Your trainer will literally try to kill you if you try some short-short VO2s like Spanish needle- I was getting recoveries at 75% of FTP and on intervals 10% above target.

Maybe it’s just me, but I have numerous examples of higher heart rate and higher RPE at the same if not lower power in ERG vs resistance mode. I really like using resistance mode too so that I can vary the cadence, especially in over-unders or long intervals with subtle changes. Only drawback of resistance mode is that its hard to adjust for wide swings in power (say 1 min or under VO2 efforts, the resistance needed to hit the power produces way too much power even in a small gear during recovery). For those, I don’t pair the trainer and just use the built-in resistance.

Yes, it does overshoot and it might even look like it tries to kill you as @mikemcvea says :slight_smile: I solved it by Cycleops H2 - couldn’t be happier. However, you can still get fast on Tacx Vortex but it sucks sometimes.

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I think that’s an easy fix. Just use powermatch and TR will use your Vectors power and adjust the Vortex resistance accordingly.

I use a Tacx flow with Assioma Duos in powermatch mode, and I’m pretty happy with the setup.

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I’ve dealt with it up till now so I guess I’ve actually been training a bit more and becoming marginally faster :joy::sweat_smile:

Are the cheap Tacx the only trainers with this kind of issue?

And would you suggest using PowerMatch on my next Ramp Test (ie, is it reliable enough?) or simply record my power meter with my garmin, take the FTP from there, and then evaluate if to use PowerMatch in the rest of the “normal” training?

I think you should use on your Ramp Test the same powermeter you intend to use on your training (indoor and outdoor). I use my assiomas in powermatch mode to do my ramp tests without issue, they are more reliable and accurate than the Flows PM.

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My Tacx vortex performed the same as yours does. Power match is the answer :ok_hand:

I’ve had the same problem with my Vortex, I’ve found that getting on top of cadence just before the start of the interval helps smooth it out a bit.

This will be down to gearing and the trainer’s resistance floor. If you put it in an easier gear for the rest periods it will hit its targets. :slight_smile:

That’s my experience also. Just have to find the right gear for it to hit the targets.

I found that my Vortex would read 20-70 watts high compared to two other power meters (stages and powertap). I started this topic:

Vortex owners might want to look at the youtube video linked in that topic. It has a lot technical info about the vortex power curve and which gears you have to be in to reach certain power levels. I never knew that about the vortex until I did the research.

The other thing I noticed about my Vortex is that as it warmed up, its power would drift higher and higher away from the other power meters. One’s best shot with the Vortex might be calibrating after you’ve warmed it up for 10-15 minutes. Of course, this is inconvenient during a workout.