Hi.
I have been having an ongoing knee issue, so I decided this past December to go in for Bike Fit Tune ups on my road, gravel, and “trainer” bike. I decided to start with the trainer bike as it was the one I was using most frequently given the weather in the Northeast at this time of year. We made some adjustments, which unfortunately resolved the knee issue, but caused issues in adjacent soft tissue. So, I went back in for another adjustment this past week. Too soon to tell whether these are the correct adjustments, early indications are promising.
One of the changes made was to add 19mm pedal extenders to help my knees track better. This is all fine for the trainer bike, as I don’t have a power meter. I source the power from whatever smart trainer I have the bike on, currently a Kick’r Move.
My concern, my road and gravel bikes are using dual side Garmin Rallys (RK200 for the road, and XC200 for the gravel). After a discussion with Garmin support, I know that pedal extenders are not supported for two reasons (1) it will block the antenna/transmitter that is at the end of the spindle; (2) Could potentially lead to misleading power numbers because of some changes to how the strain gauge is deflected.
I am not very clear on how an extender will affect the measurement. Which leads to my next question.
I reached out to several power meter manufacturers (Wahoo Speedplay, Favero Assioma, Stages, SRAM/Quarq. All provided the same response, pedal extenders are not supported, they will import the values being reported. Leaving out Speedplay and Favero, how does a pedal extender affect the values being reported by a crank arm, spider, or spindle-based power meter?
Thanks
-marc