Originally Posted by
Mike Mills
This is why I think it might be a posture-related problem and not a "fit" problem. Do that pelvic tilt. Strengthen your stomach muscles and your gluteus maximus. This will flatten your lower back and make you "longer" rather than humped forward on the bike.
I could be entirely wrong.
I'm with Mike 100 percent on that. Working on core strength, posture, and flexibility will help many other aspects of your life besides riding a bike--digestion, circulation, sex life, and how good you look in a suit
. I also recommend working with a chiropractor if you can afford it.
And return that saddle tilt to something more closely resembling horizontal--you might be unconsciously pulling yourself up on the nose to ameliorate the sensation of sliding off the back.