The motor's field swithcing option allows driving mods optimal for both racing and city driving. Series field mode gives lower rpm and higher torque both at a reduced amp draw making it ideal for the typical city conditions with frequent starts/stops and low average speed. Switching to parallel field mode increases rpm and nominal amp draw while decreasing torque a bit. This, however, doubles the copper cross section in the stator, greatly increasing overload ability. The result is a motor which can survive severe overloads while keeping rpm high so very little gear shifting is needed.