RainmanP

I've noticed that at my LBS they just use the large plastic-coated hooks designed to hang bikes in the garage. HOWEVER, they use them in an innovative way. Rather than screwing them to the ceiling they use one hook per bike screwed into the wall at a downward angle, probably about 45 degrees but probably not critical. They actually have them screwed into a 2x4 ripped with the appropriate angle, but that is probably not really necessary as long as there is room for the hooks to turn as you screwe them in. The hooks are place about 6 feet off the floor with the hook open to the side rather than up. Hanging a bike by it's rear wheel both tires rest on the wall. They have all their repair bikes hanging like this, maybe 40 bikes, and none has ever fallen despite the inevitable bumping. As far as I can tell as long as you have some downward angle to the hook, the exact angle and distance of the hook from the wall is probably irrelevant. Those hooks are only a couple of bucks apiece at Home Depot or Lowe's so you can't get much cheaper.

Forgive me if this is painfully obvious, but make sure you screw them into studs, not just drywall, and drill a pilot hole a little smaller than the screw threads at the selected angle before trying to screw the hooks in.