Looking for a bit of advice here - did an FTP test this evening with my new Precision 4iiii left sided power meter and a Tacx Vortex smart trainer. I had the power reading on Zwift from the trainer and the power meter reading through my Garmin.
Have noticed since getting the power meter that on hard efforts outside the power was sitting a lot lower (270-290 watts) for 20 minute efforts compared to what I have been doing on zwift recovering from injury over the last few months (could easily hold 320-330 for 20 minutes).
Did 20 minute FTP test today with average power for the twenty minutes on zwift of 375 and on my power meter of 285!!! My previous FTP in October when last checked was 314 on Zwift.
Does anyone have any tips for what to do here - I checked my trainer calibration on the Tacx app at the end of the ride and it was in the green zone. Is Zwift just massively over estimating my power??
Trust the power meter power output readings not the Tacx. I’m running a 4iiii and they are quite accurate (and close to my Hammer’s power output). Unless you’re really unbalanced in power there won’t be that much of a difference between left and right legs.
All you have to do on Zwift is select the power meter as the power source and you’ll get accurate power readings. Your FTP from the Vortex was probably higher than it really was.
If you’re using a power meter or smart trainer, Zwift only reads the data that’s being sent to it, so any differences in readings are going to be between the power meter and smart trainer.
That being said, there can be differences between sensors, as everyone has noted. Be sure you calibrate both.
Power meter is accurate, zwift zpower has a heavy edge to it. It will generally be much higher than actual power. I’m told a future update will correct zpower. Until then, it’s like having a turbo on the bike.
Power meter is accurate, zwift zpower has a heavy edge to it. It will generally be much higher than actual power. I’m told a future update will correct zpower. Until then, it’s like having a turbo on the bike.
I have 4iiii and Tacx Vortex and have found that the Vortex takes at least 5 mins to warm up. Once warm and calibrated it is pretty close to the 4iiii.
But make sure that when you calibrate the Vortex, it is at the end of the ride when it is good and warm otherwise I find it gives quite different readings to the 4iiii.