Good questions. I'd actually ridden the same road at about the same time of day just the day before, but with my usual stoker who weighs probably 20 lbs more.
Didn't experience the same thing, but we might have been going a tiny bit slower.
Maybe I was a little nervous, because this was the stoker's first tandem ride and she'd never been on a bike at that speed before. But she wasn't nervous at all. In fact, it was amazing that we rode the same hilly 15 mile route averaging a couple of mph faster than the day before
