Like most of us, I assume, I hang my bikes from the ceiling. Screw plastic-coated hooks (found at any hardware store for 50 cents apiece or some such), into the 4"side of a two-by-four, on 9" centers for maximum storage efficiency. Use 1/4" lag screws to screw the 2x4 into the studs in the ceiling. You can store 10 bikes on one 8' 2 x 4. If you want a little looser clearance, go to 10" centers...I've found 9" ok for most applications, if you're reasonably careful about getting the bikes in and out of their spots...if you're worried about damage, just put some foam insulation over the top-tubes. Easy enough to remove for use.
This method works as well for wall mounting, but stress on the lag fasteners is greater, unless you screw the hooks into the 2 x 4 at a downward angle, so that stress is reduced. I always secure to the ceiling...gives more space on the floor too, and, heaven knows, I need it.
Charles "too many bikes, not enough time" Andrews beautiful south Orange County CA
"Even in such a time of madness as the late twenties, a great many men in Wall Street remained quite sane. But they also remained very quiet. The sense of responsibility in the financial community for the community as a whole is not small. It is nearly nil."
--John Kenneth Galbraith *The Great
Crash of 1929*