IMO Your OB will discourage you, if it was 30 miles a day, maybe, but not 50-84. It will be your decision of course, totally your call and she won't be interested in your peeps from the interweb's opinions, her job is to define you as a risk, and manage you as such. Fetus is about a half ounce, increased blood volume, potential for feeling like **** as you sometimes do at the time of pregnancy, will you actually enjoy the ride worrying about your decision? Were you riding alone? How will this impact your group if not?