[flameout]

I ran a quick test as well (not graphing the data or anything, just dumping it to the standard output) and found a similar amount of variation. I was using whatever WPILibJ defaults to for encoder decoding (1X? 2X? 4X?).

For what I'm writing, however, manual differentiation (to those who don't know what this means, it's the method Ether wrote in the last post) is easier to implement and completely effective.