How To Measure A Bolt Pattern On A Hub And Drum Assembly

Updated 10/11/2010 | Published 10/10/2010

Question:

to measure hub-drum for bolt circle, do you measure center-of #1 hole to center of # 3 hole? I have been told, from outside hole #1 to center of hole # 3 ?.

asked by: Jim B

Expert Reply:

To measure a bolt pattern it will always be from center of bolt hole not the outside of the bolt hole.

If you have a bolt pattern with an even number of lugs you will measure from center of one bolt hole to center of the bolt hole directly across from it. If you have a bolt pattern with odd number of lugs you will measure from center of one bolt hole to the point halfway between the two bolt holes directly opposite from the first.

I am sending you a link to a FAQ page and a link to a video that will show you how to measure a bolt pattern.

expert reply by: Jeff D