A bearing section for a mud lubricated drilling motor comprising a housing having an inner bore, a mandrel at least partially disposed within the inner bore of the housing, a thrust bearing disposed around the mandrel and within the inner bore of the housing, a lower radial bearing disposed around the mandrel and within the inner bore of the housing, the lower radial bearing positioned below the thrust bearing, the lower radial bearing having an outer cylindrical member including an inner surface, and an inner cylindrical member disposed within the outer cylindrical member of the lower radial bearing and having an outer surface, the bearing section characterized in that: one of the inner surface of the outer cylindrical member of the lower radial bearing or the outer surface of the inner cylindrical member of the lower radial bearing includes a flat profile and the other includes a series of circumferential grooves [84, 100], the lower radial bearing further includes a series of spherical members disposed within a space between the inner surface of the outer cylindrical member of the lower radial bearing and the outer surface of the inner cylindrical member of the lower radial bearing, wherein each spherical member of the series of spherical members of the lower radial bearing engages one of the circumferential grooves of the series of circumferential grooves [84, 100] of the lower radial bearing; and the bearing section further includes an upper radial bearing [54, 58] disposed around the mandrel and within the inner bore of the housing, the upper radial bearing [54, 58] positioned above the thrust bearing, the upper radial bearing [54, 58] includes an outer cylindrical member including an inner surface, an inner cylindrical member disposed within the outer cylindrical member of the upper radial bearing [54, 58] and having an outer surface, one of the inner surface of the outer cylindrical member of the upper radial bearing [54, 58] or the outer surface of the inner cylindrical member of the upper radial bearing [54, 58] includes a flat profile and the other includes a series of circumferential grooves [84, 100], the upper radial bearing [54, 58] further includes a series of spherical members disposed within a space between the inner surface of the outer cylindrical member of the upper radial bearing [54, 58] and the outer surface of the inner cylindrical member of the upper radial bearing [54, 58], wherein each spherical member of the series of spherical members of the upper radial bearing [54, 58] engages one of the circumferential grooves of the series of circumferential grooves [84, 100] of the upper radial bearing [54, 58]. one of the inner surface of the outer cylindrical member of the lower radial bearing or the outer surface of the inner cylindrical member of the lower radial bearing includes a flat profile and the other includes a series of circumferential grooves [84, 100], the lower radial bearing further includes a series of spherical members disposed within a space between the inner surface of the outer cylindrical member of the lower radial bearing and the outer surface of the inner cylindrical member of the lower radial bearing, wherein each spherical member of the series of spherical members of the lower radial bearing engages one of the circumferential grooves of the series of circumferential grooves [84, 100] of the lower radial bearing; and the bearing section further includes an upper radial bearing [54, 58] disposed around the mandrel and within the inner bore of the housing, the upper radial bearing [54, 58] positioned above the thrust bearing, the upper radial bearing [54, 58] includes an outer cylindrical member including an inner surface, an inner cylindrical member disposed within the outer cylindrical member of the upper radial bearing [54, 58] and having an outer surface, one of the inner surface of the outer cylindrical member of the upper radial bearing [54, 58] or the outer surface of the inner cylindrical member of the upper radial bearing [54, 58] includes a flat profile and the other includes a series of circumferential grooves [84, 100], the upper radial bearing [54, 58] further includes a series of spherical members disposed within a space between the inner surface of the outer cylindrical member of the upper radial bearing [54, 58] and the outer surface of the inner cylindrical member of the upper radial bearing [54, 58], wherein each spherical member of the series of spherical members of the upper radial bearing [54, 58] engages one of the circumferential grooves of the series of circumferential grooves [84, 100] of the upper radial bearing [54, 58].