Posted by Herb (207.200.150.64) on November 07, 2003 at 16:25:50:
In Reply to: Re: Tacx Calibration Follow Up posted by Joe Scho on November 07, 2003 at 12:25:02:
: For calibration purposes using only the speed reading, obviously speed is very important: You are using this in the calibration procedure whether you use 30 Km/h or 40 Km/h as your starting point in a roll-down test. From what I understand, at the zero resistance setting the speed calculation does not incorporate body mass or height or any other parameters. It makes sense to me to use the pressure on the tire as a way to calibrate the system and not play around with the "scale factor".
It doesn't make any sense to me at all to not use the scale factor. With the scale factor set at the factory default of 100 and the Tacx programmed at 200 watts, my Power-tap showed that I was actually pushing around 230 watts!! There is no way to fix this just by playing around with tire pressure and roller pressure! In fact adding more pressure to the tires and the roller would only make the error worse while decreasing the pressure would make for unacceptable tire slippage on the roller.