::: USS has entered the chat :::

In my experience, SAE is typically associated with fractional inch fine thread fasteners, and USS with coarse thread. Admittedly, most bicycle threads are fine thread.

But many common bicycle threads are neither SAE nor USS. A common example is the standard axle thread of 3/8-26, which is close to (but incompatible with) SAE 3/8-24, and is close to (and partially compatible with) M10x1.0 very fine metric thread.