http://shop.pbisprockets.com/product...&categoryId=56
Custom built blanks, drill your own holes.
Blank 428 Steel Rear Sprockets.
Blank Steel Rear Sprockets, available in 428, 520 and 530 chain sizes. With 1.0in. center hole. No lightening holes or bolt holes.
High Quality Carbon Steel - 45C:
They have 47 to 57 teeth options. I'm thinking I can use the old sprocket for the bolt pattern transfer to the new one. They sell aluminum or steel sprocket blanks.
They also have a custom build option to build to your bolt circle and center hole, but its always in 7075-T651 Aluminum. But the custom sprocket only comes to $50. Thats with 38mm center hole, 57mm bolt circle. And in my case I'm looking at going full on granny so maybe 50 tooth, but with option to go to 60 tooth max