It is a very simple piece, but it needs a 100% infill, because if not, it could breack while printing.
I do recomend too, to print this at TPU, as is more rubbery and it gets more grip. But pinting it on PLA would be nice too.
Thanks for sharing and downloading!!
I did this because the pulleys of my 3D printer where off and they cost 8$ to buy new ones, but you can easily print them with your printer.