I have been having some troubles with a new Ergomo unit. When I first rode the bike the power was WAY off, it was very obvious... 250W (estimated) was reading 300W.
I convinced a buddy to let me use his PT to try and calibrate the unit. The factory suggested k-factor is 182, I had to drop it all the way down to 165 to have it match the PT. The PT and Ergomo line up pretty nicely until I get into the higher power (+300W), then there is some drift with the Ergomo reading lower than the PT. the drift isn't linear, it appears to get worse as the power is increased.
My question is two part:
1 - The LBS who installed the unit admitted today that they did not use a torque wrench to install the BB. They did, however, chase/re-face the shell before installation. They also have the wires exiting at exactly 9 o'clock. Could the fact that the unit may not have been torqued properly cause this type of mis-reading?
2 - Are there other variables that could affect the Ergomo to the point that the mounted k-factor is almost 20 points off the factory specified?
I am taking the bike back to the LBS next week to have it removed and re-installed. Any suggestions on what I should tell them aside from the documented install instructions?
Thanks,
Geoff