Good information, here. I have used bb7 on the tandem for years, I know them, they stop a tandem predictably (we're not going down monster mountains with them tho). We did just start having and issue with them ... when we go over a significant bump one pad in the rear dislodges and jams against the rotor; braking is unpleasant when unexpected. The pads are held in by magnet so that seems to be a design issue, best guess, though it's taken years for this issue to start. So I'm looking to try something different. I will replace the pads on the tandem's bb7 and make sure the spacing to the rotor is small which might resolve this issue.