Losing wattage on Zwift through Tacx Vortex Smart

Hi all, loving the zwift, particularly the workouts. having had my FTP increase from around 300 to 330 over a period of about a month but in the last week I have noticed that, in the last week the power I am generating seems to have dropped quite dramatically. I have adjusted the trainer difficulty but my understanding is that should not affect wattage. The only other thing I have changed is pumping my tyres up. Could this have such an affect? I calibrated it before and after and both were in the acceptable zone.


Hello Simon.

Wheel-on bike trainers are definitely sensitive to tyre pressure. Your Vortex will calibrate accurately at any reasonable tire pressure, but different tyre pressure will lead to a difference in Watts output. Unless you want to calibrate before every single ride you’ll want to decide on a consistent tire pressure to maintain and be consistent with it

Tacx recommends 7-8 bar (~100-120psi). To keep things simple you should keep your pressure at the same psi you use for riding outside.