Welcome to Healing Well!
It sounds like you're definitely in the right place. Chronic GERD is a different experience for different people. Some suffer much more than others, with food and acid refluxing into their mouths on a daily basis. Others only suffer with intermittent heartburn, and still others have GERD related lung problems, or hoarseness. I'm sure you've surfed the net looking for answers, and probably already checked out this resource, but just in case, check this out for more answers...www.medicinenet.com/gastroesophageal_reflux_disease_gerd/article.htm
I can see why leaning forward to ride a bike could cause problems with reflux. One suggestion would be to be sure you don't ride after eating...when your stomach is full, it puts more pressure on the LES valve that holds the acid and food in your stomach.
Be sure to stick around. I'm sure others will be by to share their experiences and support.