Why Are Tacx Trainers Suddenly Boosting Your Power? (And How to Fix It)

Why Are Tacx Trainers Suddenly Boosting Your Power? (And How to Fix It)

With the update Wednesday to game version 1.0.64913 many – like really many – have suddenly experienced crazy power numbers when using one of these trainers:

  • Tacx Boost
  • Tacx Booster
  • Tacx Blue Matic
  • Tacx Blue Motion

The problem is not with your speed sensor, nor the trainer itself. Rather, Zwift has introduced a bug. It changed the power curves for these trainers which is defined in-game and used to translate speed to power.

We’ll have to wait for Zwift to fix it for real but in the meantime you can get riding with realistic numbers simply by selecting a different trainer model from the list in the pairing screen.

I dug into the defined power curves and found what seem to be fairly close matches:

  • Choose Jetblack M5 Mag Pro instead of Tacx Boost
  • Choose Tacx Blue Twist instead of Tacx Booster
  • Choose Jetblack M5 Mag Pro instead of Tacx Blue Matic
  • Choose Minoura MagRide-60 instead Tacx Blue Motion

Simply choose the alternative trainer instead of your Tacx when pairing. But let the trainer resistance setting be the same as always for your Tacx – simply ignore what Zwift says it should be for the alternative trainer.

Here are the power curves so you can see how they compare. The graphs show power (watts) as a function of speed (mph) – how much power Zwift calculates you are putting into the pedals based on the speed of your rear wheel:

Tacx Boost vs. JetBlack M5 Mag Pro

Tacx Booster vs. Tacx Blue Twist

Tacx Blue Matic vs. Jetblack M5 Mag Pro

Tacx Blue Motion vs. Minoura MagRide-60

Editor’s note: those article was originally published on ZwiftHacks. It is reprinted here by permission.

About The Author

Jesper Rosenlund Nielsen

Jesper lives in Vejle, Denmark and has been zwifting since 2015. He rides with World Social Riders whenever possible and also runs ZwiftHacks, the home of ZwiftMap, ZwiftPref, and other tools and hacks for Zwift riders. Find him on Strava

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Chan Stevens
Chan Stevens (@chanstevens)
6 months ago

LOL, is this something the user really WANTS fixed? I know if the little blue pill lasts more than 4 hours you’re SUPPOSED to seek medical help, but…😉

James Ryan
James Ryan (@james-ryan-marvell)
6 months ago

I can imagine there is a storm of rider chasing up the Alpe de Zwift as this appears.

M. D. S. Günther
M. D. S. Günther
6 months ago

I just had my best race ever, using a Tacx. Those 15 seconds until I realized it’s not my product… Not pretty 😅

Greg Tulloch
Greg Tulloch
5 months ago

Does anyone know if similar problems exist for BKool trainers? Sometimes I turn out silly numbers which, whilst nice, ruins my ZwiftPower category listing and I get completely thrashed when racing.

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