[BrianG]

It's really the torque curve vs rpm. Nitro engines have low power at low rpm, which BL has high power at all rpms. Naturally, when a tranny shifts up, the rpms drop. In a nitro setup, the lower rpms results in lower force on the gears. In a BL setup, the torque actually is higher because more current is being drawn to drive a taller gearing (torque is proportional to amperage). That high force "snap" during shifting is what causes the breakage.