Measuring disc offset?

[Bitza]

Hi an awkward question, what does the offset of a brake disc actually mean? Is it measured from the hub/disc join, out to the side of the braking surface of the disc or to the center line of the braking surface? Not as obvious as I had assumed.

[Mr Gazza]

Usually the disc offset is as you say, from hub face to outside of the disc.
Or the entire thickness of the disc and carrier (Excluding any carrier bobbins that might be above the disc surface.)

Be warned that some sellers, particularly on eBay, don't seem to understand that, and you do get some strange interpretations sometimes!

I sourced some spacers available in bespoke thicknesses should you need any.

[Dukedesmo]

As above, from hub to outside of disc, as per this cross section where, F = offset;