Variable gear ratio mechanism variably sets {HEAD ~ a ratio} defining {TAIL ~ a pivot angle} of steered wheels of the vehicle to a steering angle of a steering wheel of the vehicle 
defining
Variable gear ratio mechanism variably sets { HEAD ~ a ratio } defining { TAIL ~ a pivot angle } of steered wheels of the vehicle to a steering angle of a steering wheel of the vehicle
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH