I'm running a 1.5 inch roller (few hills) and I weigh 135 dripping wet. I took it pretty easy on the motor 'till I had about 200 on it (not really, but I tried). Also, I'm running a City Slick on the front and a pretty slick Armadillo on the back. Both with 60+ lbs air. I disassemble, clean, and White Lithium grease every bearing surface on the bike annually. Finding the exact pressure of the roller on the tire is also important.
I'm gettin old, For me it's not ALL about the speed. It's about being able to go places these old legs won't easily get me. And not paying much for it (relatively).