Watts dramatically over-estimated!

Hi all!

I recently took my road bike out for the first time having been Zwifting for about 8 weeks! Absolutely loved it, but weather has been a bit crap so back onto the trainer.

I have a Tacx Blue Matic dumb trainer that I use with the garmin speed and cadence sensor 2. Prior to this outing, I was getting much more realistic wattage read on zwift. My FTP was predicted around 165 weighing 75kg at 6’1, with not that great a base of fitness. For some reason, now my watts are sky high and ridiculous. I completed the ramp test yesterday, having to go harder than the test suggested and set my FTP around 900 - who knew, should’ve been a professional cyclist. I did get a tire slippage message just before this all started but I’ve troubleshooted this as best as possible.

  • I’ve tried repairing the garmin sensor with my phone, and same with Zwift.
  • I have set up my Tacx Blue Matic as per manufacture instructions with regards to tire pressure, resistance level (3) and the number of turns for the “wheel on” part of the trainer.
  • I’ve selected the right tire size

Any suggestions? I’ve searched the forums but can’t find similar issues with this setup. It’s not the end of the world because I can sort my own programs out and put in a manual FTP, but I have no idea where my FTP actually is and so not sure how to accurately gauge the workouts on Zwift which is what I signed up for.

Thank you in advance!

The update this week seems to have messed up all the wheel-on turbo trainers. They seem to be reading about double watt output. Lots have commented but not seen anything about Zwift fixing it though.

Go to this thread - March 2021 Update issues - #8