So when a group advises their ride @ ~18mph (or whatever), are they refering to start-to-finish ave. speed, or rolling (cruising) ave. speed? Not that I do group rides, too much to keep up with. I have one bike w/ a computer, routes that take me through urban areas are typically 3 or 4mph slower ave. speed than rural routes, around here (NC piedmont). Up in the NC mtns. (parkway), my ave. speeds are 4 or 5mph slower than a rural ride here. But other than noticing that, my ave. speeds are pretty consistent, and I don't expect to see them change much.