Printed for a friend who had completely and totally worn out the pulleys on his SRAM Red derailleur. Printed in red because SRAM Red.
Only issue is the SRAM Red pulleys use a 626 bearing with has a 19mm OD, which is quite a bit larger than the original hole size. So, I took the lazy approach and loaded the original STL into Meshmixer, mixed in a 19mm cylinder, and used that for a boolean cut. Didn't get it quite centered (some of the original slots are still visible, but only two of them) and it chopped through the rotation arrows, but when it's mounted up, it looks great and it works fine! Including the modified STL if anyone wants. (See the first comment on this make)
I also chose to use this design over this design which uses a 626 bearing because this is an 11t pulley, and the other is only a 10t, which logic would dictate would be a smaller diameter.. What's strange, however, is that holding the two next to each other, the diameter is almost exactly the same... that doesn't seem like it should happen with a 0.5" pitch, but it does. Both pulleys run noise-free with a normal chain. You can see the comparison in the third photo.
Printed at high resolution only because I wasn't in a rush. Support material took a little doing to remove but wasn't a huge problem.