Originally Posted by McGuillicuddy
No way. 18 - 19" is too large for a 5'9" rider. I'm between 5'10" and 5'11" and I ride a 17.5. My friend who is around 6'1" rides a 19". I'd think that 16" may suit you well, but I would never recommend buying a bike without riding it (or one just like it) first.
I don't ride a mountain bike, but I agree. I'm 5'9" and I was told 16-17" is what I should look for if I want a mountain bike.