I can’t speak from experience regarding keeping bikes on balconies, but I do know that we had extra bikes stored in our outdoor storage shed and they began to rust eventhough they were inside the building. The night moisture is definately not good, nor is the temperature changes. We were told by our LBS to not store bikes in the garage either - our garage gets very warm in the summer and cold in the winter. So now we have several bikes taking up space in our living room as well. Not sure what to do yet, but our motto is: love us, love our bikes. I feel for you not having enough space however - hope someone can come up with a solution for you. Short of suspending them from the ceiling, I can’t come up with anything. Thanks for the link on the bike stand - I will run it by DH - that would help our situation.