I've lost about 61 pound since this time last year. My normal cruising speed has picked up from about 12mph to 14-15mph. Average speed over the whole ride has increased as well, but not as much. There's a steep hill close to the end of my usual route that I like to challenge myself with. When I was first able to tackle it last year, I got up at about 3-4 mph. The other day I did it at 5-6mph, and wasn't breathing or struggling nearly as much as I used to. I'm figuring the improvements are due in part to being stronger and partially to towing around less weight.