• Bolt Circle Diameter: The bolt circle diameter (or pitch circle diameter - PCD) measures the diameter (in millimeters or inches) of the imaginary circle on which the bolt are placed.
  

Bolt circle diameters can be listed in either inches or millimeters. Following industry trends, all bolt patterns on this site are listed in millimeters.

Here is a list of common bolt patterns and their conversions:

Bolt Pattern Conversions
mm	inches
4-100	4x3.94
5-100	5x3.94
4-108	4x4.25
5-108	5x4.25
4-110	4x4.33
5-110	5x4.33
5-112	5x4.41
4-114.3	4x4.5
5-114.3	5x4.5
6-114.3	6x4.5
5-115	5x4.52
5-120	5x4.72
5-120.7	5x4.75
5-127	5x5
6-127	6x5
5-130	5x5.12
5-135	5x5.3
6-135	6x5.3
5-139.7	5x5.5
6-139.7	6x5.5
8-165.1	8x6.5
8-170	8x6.69
bold = common reference