Originally Posted by Jonny5

It lets the tire sit nicely and not have a wad of foam on the edges near the bead. Venting the tire/wheel is a preference and situational thing. I used to vent the tire for CC foam and the wheel for open cell. Now I vent the wheel if I plan to clean and sauce regularly as the hole in the tire lets the sauce in and eats the foams. If you don't sauce, venting the tire is fine. Either works well IMO, just depends on the application.