Well, I differ on this one. I guess it depends on the racks. I can say the ones I bought with my Klose are WORTHLESS!!!!! Yes, you can cook more ribs, but by the time you add time for the fact that very little hot air can circulate between the ribs, and the jockying of racks to allow for even cooking. If I had 9 hours to cook ribs, I could use them!!!! The first time I tried them, I found that the front side of the first rack, and the back side of the last rack looked great in three hours. The other 8 sides looked pretty raw because no air circulated betwixt them! I would recommend using only every other space. you can achieve the same effect by stacking the ribs IMHO! Good luck. WM