Calibrating a Tacx Flow Ergometer

[Robert Chung]

Tacx has a line of relatively inexpensive ergometers, including the Grand
Excel, the I-Magic, and the Flow (which appears to be intended to replace
the Basic). The load generator for all three ergometers is exactly the
same -- they differ in the capabilities of the computer head unit.

According to the Tacx manuals, accuracy of the ergometer will depend on:
1. the pressure between tire and roller
2. the line voltage
3. the rider's weight

The new Flow model includes a built-in rolldown test that helps to ensure
that the tire-roller pressure is consistent. In addition, one can "scale"
the Flow's readings up or down if one has an external way to measure
wattage such as a Power Tap or SRM power meter (it has been reported that
Polar's power unit may not provide consistent readings on a trainer).
However, the Flow's manual omits any description of how to change either
the scaling factor or to take into account the exact line voltage.

The Grand Excel's manual describes how to alter the scaling factor, and
that procedure works on the Flow.

To change the scaling factor: unplug the cable to the Flow's computer
head. While holding the SET button, plug the cable back in, and continue
to hold the SET button until the display clears. Press the MODE button.
The scaling factor will be shown and you can change it with the + or -
keys, then press the MODE button again. IF YOU KNOW your exact line
voltage, you can enter it, too.

For more hints, see:
http://www.topica.com/lists/wattage/read/message.html?mid=902722761