Not your typical subfloor! I dont know of any hardsurface floors that would approve an installation over joists 48" on center. You will have better luck installing a floor thats floating rather than one thats fastened to the floor. When you walk on the floor can you tell if there's movement? If there isn't any movement, and it's a small space, you might not have any problems. Make sure the floor is flat, and you maintain your perimeter gaps I don't know why it wouldn't work. Jump up and down on the floor and see how much the floor moves. If it doesn't move then you'll be fine.