You've got road BB7s designed to work with road levers, I assume? Have you played with the adjusters on each brake? Outer pad should be as close as possible to the rotor with a bigger gap to the inner pad.
I've never locked up a wheel with BB7s nor tried to do that.
My experience with BB7s on a hybrid and a couple of recumbents has been positive. The braking is consistent. Doesn't make me any faster........