We’re on the second floor of a four-story condominium and when I'm riding two bikes, I keep them both and just inside the narrow entrance to our unit, leaning against the bench seat pictured below. One is an ultralight carbon fiber bike and the other is a heavy-duty beater mountain bike. The MTB is pretty heavy, and I have a back injury that makes it a chore to carry up the stairs.

This winter I am only using the mountain bike and I decided to keep it in the vestibule of the condo at near street level. The only other condo owner who might object is spending the winter in Mexico. By April when he comes back, I'll (hopefully) mostly be using the carbon fiber bike. I gotta watch the woodwork though.

It is partly visible through the door window, but it's a strong door with a good lock and a security camera.