... bearing bar is 20 x 3 to 100 x 10;the specification of I-section ... Pitch / center to center: 12.5, 15,25, 30, 30.16, 32.5, 34, 40, 41.25, 45, ... 50, 60, 60.32, 80, 100 mm etc, also be according to client's requirement ... and 30, 40, 60mm are recommended,America standard is ... / center to center: 38, 50, 76, 100, 101.6mm etc, also be according to client's ...