rhm

While I admire the "I don't care how fast I go, or my average speed" attitude, it is not realistic when it comes to planning. You cannot plan a ride with other people unless you know how fast you all ride; you cannot plan a long ride unless you have some sense of whether you have time to finish it.

I like to ride a century every month, or sometimes a double metric, and aspire to longer rides, like triple metric or a double imperial century or whatever. But when we get over 125 miles or so, "how fast do you go" quickly translates to "how far can you go (in the time available)" and these are not rhetorical questions.

I find a century usually takes around ten hours when I'm by myself; more people means more time, not because you go slower, but because you spend more time not going. Average moving speed will be in the 15 - 16 mph range.