The Shimano diagrams conveniently include the thickness, so it would be easy to manufacture the part to spec. For 9-speed Shimano, the separate spacers ar 2.56mm thick. I reckon a 2.5mm BB spacer would be close enough, and there should be plenty of those floating around in parts bins.
The Shimano diagrams conveniently include the thickness, so it would be easy to manufacture the part to spec. For 9-speed Shimano, the separate spacers ar 2.56mm thick. I reckon a 2.5mm BB spacer would be close enough, and there should be plenty of those floating around in parts bins.