An over-bit backreamer. The backreamer is configured to be placed over a bit without detaching the bit from a drill string associated with a pilot bore. The backreamer has an internal surface that conforms to a steering surface of the bit. Rotation is transferred from the bit to the backreamer at the internal surface. The backreamer further defines a flange which interacts with a feature, such as a heel, on the bit. The flange and heel form a shoulder which transfers pullback force to the bit. The backreamer comprises a pullback eye that pulls a product pipe back through the borehole.