The omniscient Mike T posted this a few days ago on BOL about the
industry standard 4x4 bolt pattern and the Burton 3D pattern.

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4x4 is a 40 mm square. 3D is a 42 mm equilateral triangle. So a
strictly 4x4 disk is not compatible with a 3d pattern. Some bidning
manufactuers - Catek, Salomon, K2, and Burton themselves come to mind -
have designed disk that are "universal". This usually involves half of
the 4x4 holes being wider to accomodate both a 42 mm and a 40 mm
disntance between screws.
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Aegis wrote:
I have looked for a week RE this info, but the great google does not
reveal its secrets to me. Does anyone know what the exact dimensions
are for an "Industry Standard" bolt pattern and the burton 3-hole
patterns?