Phil Wood & Co. belt drive components utilize a 10mm width belt. For clarification on the terminology, the front belt drive component is referred to as the Sprocket, and the rear belt drive component is referred to as the Cog.

Sprockets (the front / crank component), are supplied with a lip on the outside - furthest from the frame

Cogs (the rear component), are supplied with a lip on the inside- toward the center of the frame.

Centerline of the sprocket or cog is defined as the point 5mm on the tooth from the lip of the belt drive component

It is imperative, in the belt drive system, that the bottom bracket shell and the rear axle be parallel. Any misalignment will cause either the belt to rub against the lip, or cause the belt to work its way off the sprocket and cog.

BELT DRIVE COMPONENT DIMENSIONS

Paul Component Belt Sprocket Dimensions (pdf)