I've hung a number of bikes, including a 80s Holdsworth tandem (531 steel, no idea how much it weighs but definitely more than the other bikes!) using the RubberMaid FastTrack vertical bike hooks. I used an older version (the 5E02) that's no longer produced but I found a whole box of them at a nearby Home Depot:
The 5E02 has two holes in the mounting plate so I was able to screw them directly into the studs (using 2 1/2" deck screws, I believe.) They've had bikes in them for about 4 months now with no signs of slippage/looseness. Here's what it looks like in action:
I really like the two cheap brackets that I bought at Home Depot or Wall Mart or somewhere. They allow the bike to tuck up against the wall higher. You just have to watch the oily chain if you walk in that area often. Each bracket comes with foam padding on the arm to protect your paint.