After the old Preston system, but before going to the current micro-disc, Ride had four different types of toothed mounting discs. All of them adjusted angle in 3 degree increments.
This is the standard Ride disc. It's standard 4x4 and Burton 3D compatible. There is an un-pictured variation which doesn't have the threaded hole in the center to attach a disc cover.
This is the Ride Shift disc. The slots in the disc are offset by 3mm, allowing for some fine tuning of stance width, setback, or centering. I've found them to be very useful on Burton 3D boards since those don't allow much adjustment to begin with. These are very rare.
This is the Ride convertible disc designed to adapt Ride bindings to Burton Channel system. The disc is thicker and heavier than standard Ride discs and is very beefy. I suspect Ride wasn't sure what kind of stress the Channel would place on the disc, so they just massively over-engineered it to be safe. Even though the disc has a threaded hole for a disc cover, the disc it thick enough that a Ride disc cover won't actually fit. The kits also came with beefy mounting screws with very tall heads that protrude significantly above the disc surface. The center slots provide easy viewing of the stance markings on Channel boards. These can still be found from time to time, but are become more rare.
These discs were used shortly after Ride moved Preston discs to toothed discs. They're 4x4 and Burton 3D compatible. They're made of thinner aluminum and have a smaller toothed area than the later discs. In some cases these offer more stance options than Ride Shift discs, and sometimes the Shift discs offer more. Neither will offer as many options as the standard 4x4 mounting pattern. They are not compatible with disc covers. These are very rare.
For reference, this is the current Ride micro-disc. It's compatible with both 4x4 and Burton's Channel, but is not compatible with the older Burton 3D pattern.
