I'm sure there are better options, but when I was 330 lbs (6' 2") I bought a Cannondale Quick 5 and it worked great. I made sure to get the right frame size. I'll jot down some thoughts that I did or experienced.
- I thought that TYPE of bike did GREAT for me.
- I bent rims more than I would hope. I bought beefier rims, in a 28mm width. THAT really helped and made for a happier experience.
-- I put 25's up front.
- I added bar ends to give me an option for hand position. Amazed at how well that helped.
- I trained for and completed a 100-mile ride on this bike, and I'd do it again if needed.
As I lost weight, I rewarded myself with an endurance class bike. This class is more of a stretched out road bike and is designed for people who want to regularly do 40-60 milers. Though I like that distance, I got it because of my height and a weight I'd never get below (230 lbs is thin for me).
Like many here, I bounce on my weight. When I go up I get my Cannondale out and ride it until I done suffocate myself bending over for my other bike.