Friendly reminder to periodically check your smart trainer PM calibration.
Moving from mainly outdoor riding to an indoor block I felt many workouts I’d done before seemed a lot harder, and AI FTP dropped my FTP after a base block despite what I felt was very solid training effort.
Running two different PM-equipped bikes on my Kickr Core confirmed the Kickr was reading ~10-12% low. This required a factory spin down to resolve, a normal spin down didn’t fix it. Now reading ~2-3% lower than two different spider based PMs, which makes sense given drivetrain losses.
Notably, about 9 months ago I had the opposite issue, this same Kickr was reading ~10% high relative to on-bike PMs. (I have 2 bikes with SRAM/Quarq spider PMs and another with Assioma pedals, and these all seem to match pretty well.) I’m curious if others have also seen this amount of drift over time, or if this is a sign of an issue with my Kickr. It’s now ~5 years old and has seen several hundred hours of hard use (FTP is in the 350-375 range so the resistance circuit gets a workout.) Flywheel bearings still seem smooth. Does a trainer lose accuracy over time? Or is this amount of drift expected and we all just need to do a factory spin-down a couple times a year?
A brief update following a chat with Wahoo tech support: They maintain that as long as a trainer is mechanically sounds, it should have a near-infinite working life. However, they also note that as trainers age and accumulate hours of use, they may need more frequent calibration.
I figure my 5 year old trainer with probably 5-600 hours use counts as “well broken in” by now, so I’ll be checking its calibration a few times a year.
Thanks for this. My kickr core is reading about 15% (!) lower than pm and it seems not accurate in terms of hr and rpe. Will try the factory recalibration.
Hey that means you’ve been working 15% harder than you thought and your FTP is that much higher! Last spring I thought I was hitting all-time bests but turned out my trainer was reading high, definitely somewhat deflating….