Hello - I’m really sorry if this one has been done to death but my power readings seem to have gone haywire of late.
A Zwift FTP ramp test yesterday that gave a rather fanciful result caused me to run a few quick tests today and I seem to be experiencing a 20% disparity between the Kickr Core in erg mode and my LH Stages power meter (on a SRAM Red carbon crank.)
I ran a spindown on the warmed up Wahoo and zeroed the Stages before starting a couple of 10 minute tests.
When Zwift was running the Wahoo at 240W, the Stages read an average of 202W.
Pushing the resistance up a little, the Stages read only 247W when the Wahoo was set to 295W.
I recall that the disparity was only 10-15W back last summer. I collected the Stages data on a Bolt that wasn’t linked to the trainer.
Can anyone shed any light? Is this common? Is there a solution?
Change the battery on the Stages and re-calibrate.
You’re comparing two different things - Left power x2 (Stages) and total power (Kickr Core). You’ll never know which is ‘more correct’ as the single sided Stages is influenced by any left/right balance.
Is there a power balancing option in the Stages app like there is in the 4iiii app, where you could set things so it thinks more of your power comes from your right leg and then hopefully get consistently similar numbers to the Core?
All being well, this would simply give similar numbers on both power meters, it wouldn’t prove one was more accurate than the other.
The Stages’ battery has been changed and unfortunately there’s no way to recalibrate / adjust it further.
I take the point about left leg / right leg but that doesn’t account for a 50W difference.
My hunch is that something’s up with the wahoo. My FTP has been around 360W for years and it was 363W when I last measured it on the Kickr in June. However, it’s now bounced up to 407W without any significant changes in training.
Do any 3rd parties offer a calibration service for these trainers?