Here are my quick calculations. Half the 135mm rear frame is 67.5mm. The 28T Gates cog is 10mm in from the right side, so it's 57.5mm from the frame centerline. The BBS02 drawings I have say the BBS02 sprocket mounting surface is 50mm from the centerline, so without even moving it inward via a spider adapter and the 50T Gates sprocket offset there is 7.5mm to work with. Not sure there will be enough room to use both Origin-8 wide black support spacers, but it looks like belt alignment won't be a problem if those numbers are correct.
