The bolt pattern of a wheel is
expressed in number of bolt holes X the
diameter of the imaginary circle through the centres of the bolt holes.
In case of a pair number of bolt holes, the diameter of the imaginary circle
through the centres of the bolt holes is equal to the distance between the
centres of 2 straight opposed bolt holes.
In case of an odd number of bolt holes it's not that easy to measure, because
there isn't a straight opposed bolt hole, here the only possible way is to
measure with the diameter of the imaginary circle.
Now, measuring with imaginary circles, and even measuring the distance between
the centres of 2 straight opposed bolt holes over the centre cap of a mounted
wheel certainly isn't simple.
Therefore the calculation below, where we are able to find the
bolt pattern with as only input tne number of bolt holes and the side, being
the distance between the centres of 2 adjacent bolt holes.
This calculation uses the
following formulas :
X = tne number of
bolt holes
Y = the
diameter of the imaginary circle through the centres of the bolt holes
Z = the side, being
the distance between the centres of 2 adjacent bolt holes
Z = Y * COS((180  (360 / X)) / 2) (calculation with a scientific calculator)
Z = Y * COS(((180  (360 / X)) / 2) * PI() / 180) (calculation with Microsoft
Excel = RAD instead of DEG)
1 inch = 25,4 mm
