Did a small ramp test on the CompuTrainer at the cottage using my Winter bike PowerTap wheel. I'd been suspecting that the PowerTap might be reading a bit low and this proved to be the case. Between about 175W and 300W the PowerTap was reading about 10W below the CompuTrainer Lab Pro.
I'm not going to worry about this as I use the PowerTap as a data gathering tool rather than as a tool to guide my training or to do my tests with, I'd be more concerned also if the PowerTap was telling me my output was higher rather than lower! After the performance of sending the unit to Prague to have the bearings replaced I'm sure not going to send it again to be calibrated, I might if a UK agent opens up but not before as it's not essential.
I can't help but wonder if the apparent reading difference might be due to the lengthy period of very low temperatures we have been experiencing and the temperature sensitivity of strain gauges. My gut feeling is that this variation might just disappear when/if the warm weather comes, we shall see.
[Uploaded 24/01/2009 22:01:06]