I was on my TT bike with 165mm cranks today and for whatever reason not using power match instead TR was taking power directly from my Tacx Neo 2T. This was the first time that I noticed a very large discrepancy vs. the power my head unit was displaying via my Vector 3 pedals (correctly calibrated to 165mm). Does anyone know why this might be?
Always in the past when I have used my road bike with 172.5mm cranks I’ve been surprised by how closely the Neo and pedals have tracked, but this time the Vectors were reading lower by between 5% (when at 120% of FTP) and 15% (when at 40% of FTP). This seems too much to be a case of drive train efficiency.