This is a bit of an odd one I think so I’ll cut out as much fluff as I can.
So, when on the trainer and I’m riding in the small chainring the RPE drops by one or two levels if I drop into an easier gear on the back whist maintaining the same power output as reported by my trainer’s power meter to TR/what I see on my laptop.
Curious to see what was going on I decided to record a ride whist the trainer was controlling the power but also to see what my power meter pedals (Assioma duo’s) were reporting.
When the watts we low say during a warmup/rest between sets the trainer (tacx Flux) and the Assiomas power matched close on my head unit to what TR/my trainer was reporting.
Now where it gets weird.
I just finished a threshold workout and during the work sets whilst in an ‘easier’ gear on the back, the Assiomas were reporting my power to be 15 to 20 watts lower than what I was seeing on TrainerRoad/what my trainers power meter was reporting but TR was still telling me I was holding target power.
I shifted into a harder gear, the RPE went up, the power reported by the Assiomas would more or less match what TR was reporting but the power as reported by TR stayed the same - it didn’t change at all.
Dropping back down a couple of gears the power reported by TR stayed where it should be, the RPE dropped and the Assiomas started reporting my power to be 15 to 20 watts lower than TR.
I get that power sources are different etc but I’m pretty sure that my trainer/TR is reporting my power as being 15-20 watts higher than it actually is when riding in a lower gear (I think the Assiomas are reporting correctly).
I’m not sure I’ve explained this well but I have the FIT files and happy to share and if anyone cares to take a look and I can pinpoint the time when I was riding during an interval in an easier vs harder gear so it possible to see the variation, it’s kind of hard to take screenshots to illustrate the point but I’ll give it a go.
So this is the first interval of the workout as report by TR/my trainers power meter and loaded in Golden Cheetah shown overlayed with power zones (its easier to see the difference vs seeing power in watts):
This is the same interval of the workout as report by the Assiomas power meter and loaded in Golden Cheetah:
And this is TrainerRoad/My trainers data in TR:
So according to the data from my trainer I’m in the right zone, based on the data from my Assiomas I’m in sweet spot.
Does anyone know what’s going on? The variation kicks in when in an easier gear that’s the only difference.
I ride with oval chain rings as well in case that matters.
I know I could use powermatch but I wasn’t over the moon and I would really know what the root cause is.
Any thoughts welcomed!!!