- May 17, 2005
The CT comparison should reveal a large discrepancy, assuming you warm up your CT before comparing, but I wouldn't count on the CT revealing a small discrepancy (e.g., 10W). When I first got my CT, I compared the CT watts with my PT watts after warmup and using the CT procedures for setting press-on force and the rolling resistance calibration routine. I found that the CT was off by enough (although I can't remember the number now) that I decided to set my press-on force more precisely and not rely on the CT rolling resistance calibration routine. So, I machined an adapter out of aluminum for using a precision torque wrench to set the press-on force. That procedure allows me to get within 1-2 watts of my PT, but I have to change the torque force slightly as my tire wears. Also, I have run MAP tests for other cyclists on my CT and I have found huge variances in the amount of torque force depending on what tire they were using. When I say huge, I mean a range of about 40lb-in - 75lb-in, depending on the tire.Originally Posted by bgoetz .
What if I put my bike on the computrainer and compared the numbers? Would that be a good way to check the calibration? Also how do I do a manual torque calibration vs the auto calibrate?
Also, my AP now seems reasonable (196 for RR and 283 for crit), just the NP is high (316 RR and 361crit). So you still thinking calibration issue? I suppose the data could still be suspect, I do use the "auto pause" feature could this also be screwing things up?