A road transport system of a header of a harvesting machine includes two pairs of wheels and two wheel frames. Each wheel frame is connected to a pair of wheels. The two wheel frames are rotatable between a field operation position and a road transport position. A header of a harvesting machine includes two pairs of wheels and two wheel frames. Each wheel frame is connected to a pair of wheels. The two wheel frames are rotatable between a field operation position and a road transport position. A method of converting a header of a harvesting machine from a field operation mode to a road transport mode includes: releasing wheel frames of the header from the header； rotating the wheel frames from a field operation position to a road transport position； and enabling kingpin steering connections between at least one of the wheel frames and a pair of wheels.
