Originally Posted by interested
So some real world examples shows sprocket thickness varying between 22% and 33% thicker than my cassette, even considering the ramping grooves, it really isn't that much of a difference, but for arguments sake let me say that +50% more thickness equals 50% longer wear (linear). That means that if I spread the wear on my cassette to only 3 rear sprockets I would still be significantly ahead considering wear.
I really don't think that a cheap BMX-style sprocket is made of the same grade of steel as a Shimano 105 cassette, and steel quality (hardness) plays a role in how fast things wear out.
I think your missing an important point. Chain stretch and sprocket wear is much less important on a ss drivetrain. It matters on a cassette because if the chain stretches it will wear the commonly used sprockets. Change to one of your less used sprockets and the stretched chain starts skiping on the virtually unworn sprocket.
That doesn't matter with ss. Who cares if the chain stretches and wears the sprocket? The chain only has to mate with a single sprocket so they can happily wear together. Even when all the wear is concentrated on a single sprocket it takes a long time for the teeth to wear down so far they stop working. Unless you are willing to only use two or three sprockets on your cassette you will be replacing your cassette when the teeth have worn much less.
Also since the chainring has no shifting ramps it can also be flipped so the chain wears the oppersite side of the tooth, this means you get double the life from your chain rings. IIRC the hub sprockets can also be flipped to double the life.