Are you working hard enough? When I started riding again I could add miles and increase speed with delightful ease. But then the speed plateaued and settled into an average that I sort of wish was a bit higher. A few times a year I ride with brother. He's an A group rider and when we're together my speed picks up a couple mph. But I also realize I'm working a lot harder than I do on solo rides. And I'm pretty sure if I did that every ride my average would increase. That's hard to do riding alone though. You have to really want it to be able drive yourself to work harder every time you go out. Honestly, I don't want it bad enough. At least I'm enjoying the ride.