WHEEL BOLT PATTERN

 

     

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.

Input

Dimensions

 

Pattern

Side

UNIT

Bolts - Diameter (mm)

mm

X  mm
  X  inch
Bolts - Diameter (inch)

inch

X  mm
  X  inch
Bolts - Side (mm)

mm

X  mm
  X  inch
Bolts - Side (inch)

inch

X  mm
  X  inch

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

 

 



 

Updated : april 03, 2006 - 01:49 CET