FYH Bearing UC218-56 3-1/2" Axle Insert Mounted BearingFYH Bearings Mounted Bearings UC218 56 3 1 2" x 3 1 2" x 3. 78" 3 1 2" mounted Bearing, UC218 56, measures an inner diameter of 3 1 2", a standard bearing size commonly used in a variety of industrial and commercial applications. d = 3 1 2" D = 3 1 2" B = 3. 78" C = 1. 496" Ca = 0. 433" S = 1. 563" S1 = 2. 217" S2 = 0. 591" Bearing No = UC218 56 Basic Load kN (Cr)= 96. 1 Basic Load kN (Cor)= 71. 5 Mounted Bearing Bearing Size: 3 1 2" x 3 1 2" x 1.