In West Virginia, the terrain is such that even with a road bike, I'll hit a mountain where I feel lucky if I don't have to put a foot down. And then I'll be going 40+mph on a descent for several minutes, doing absolutely no work. One day with a lot of back roads riding and gradients that made me want to cry, I averaged 15mph over about 50 miles. The next day, we hit a smooth rolling stretch of highway for a while, so the average went up to 17.3mph for 60 miles with a double rotating paceline. Obviously, those who could climb the mountains those days and had a weight advantage on the descents averaged much higher than me. Would I have sustained my averages solo? No. Would I have done that on a mountain bike? Hell no. Does it matter? Not at all.

It's nice to have some time and speed goals. There's a rolling 21 mile loop I like to do when I'm short on time as a kind of TT practice (it takes me a few rollers to warm up, and the fast part of the course is the back side). I only do that route by itself occasionally (usually it's part of a longer ride), and it's nice to see if I improve over time. It's also nice to be out there chasing a number on my cyclocomputer. However, I don't think there's a speed I *should* be going. If it was an actual race, I'd think I'd need to go a certain speed to have a good chance of placing well, but that's racing.

If you want to go faster, work on going faster, but there is no magic number you should be shooting for that will make you an adequate bike rider or anything. That speed may vary greatly depending on what terrain you hit, wind conditions, etc. The more you ride, the more you can use your previous rides as a good frame of reference, but there's no need to compare yourself to any of us who ride different bikes in different places.