This is a WAG on my part, but looking at nancysv's post and valygrl's post, I think rider weight has a great impact on BOB handling. I'm 300 lbs, I've ridden with my bob empty, with a moderate load(gear for an self supported tour) and a heavy load(two bundles of firewood plus 24 lbs of ice). With an empty BOB, if it weren't for the rattles when I went over road imperfections, I'd barely know I was pulling anything, no matter what the speed. With any load, I found low speed handling a pain, and the bike would get kind of squirrelly, especially my road bike. With a heavy load, descents were more of a handful, and I definitely had a feeling of the trailer trying to push me around, but it never felt unmanageable. My guess is that tandems/triples are great companions for a bob, with their extra weight and long wheelbase.