Chainring SAMOX E-bike BCD104 steel black. 40T.

Steel bottom bracket for E-bikes.
40 teeth
Chain pitch 1/2"
Chain width 3/32", for 11/128" chains
4-bolt mounting
Color: Black
BCD/cross hole spacing 104mm
Weight: 160g
Measuring the hole spacing of the sprockets
In the 4-bolt model, measuring the screw spacing:
measure the screw spacing between adjacent holes
In the 5-bolt model, measuring the screw spacing:
generally use the attached measurement table for help.
Number of bolts in the sprocket Length between two different holes Cross hole spacing
mm. inches (PCD/BCD)
4 45.3mm. 1.78 inch 64mm
4 56.6mm 2.23 inch 80mm
4 62.2mm 2.45 inch 88mm
4 66.5mm 2.62 inch 94mm
4 67.9mm 2.67 inch 96mm
4 72.1mm 2.84 inch 102mm
4 73.5mm 2.90 inch 104mm
4 84.9mm 3.34 inch 120mm
5 43.5mm 1.71 inch 74mm
5 55.2mm 2.18 inch 94mm
5 64.7mm 2.55 inch 110mm
5 76.4mm 3.01 inch 130mm
5 9.4 mm 3.12 inch 135mm
Calculation chart for calculating bolt spacing on the outer rim:
4-bolt:
Distance between adjacent holes divided by
0.7071 = bolt spacing
5-bolt:
Distance between adjacent holes divided by
0.5878 = bolt spacing