Tech A says that twin leading shoe brake systems are more efficient in forward braking than reverse braking. Tech B says that leading/trailing shoe brake systems provide equal, but not maximum, braking in both directions. Who is correct?

Both are correct

Explanation:

The two tech company are correct because when the primary side leading shoe is pressed against the drum by the wheel cylinder, the force that makes it rotate together with the drum wedges the secondary side leading shoe into the drum to achieve braking action. This type of drum brakes provides strong braking for both reverse braking and forward movement.

This is use in commercial vehicle that require especially large braking force.