There is a spacer in the OEM wheel that sits up against the roller bearing on the brake side. You need to remove that from your OEM wheel and use it with the COO wheel. It typically stays in place on the OEM wheel because there is a oil seal that holds it in place. There is no oil seal on the COO wheel to hold the spacer in place. Notice that there is a ridge on one side of the spacer, it faces the bearing.
On another note, some of COO's wheels use only the OEM spacer, some use the OEM spacer PLUS another one. Whenever you put it all together it should be pretty obvious it you need one or two based on the space between the caliper bracket and the bearing.