Threaten to move out over it, and make sure you look like you might cry. She will relent, if you use all the advice above, such as protecting the wall/floor where you keep it. She may not be aware of how valuable your bicycle is to you, so be clear that it's not a toy but a necessity, and that you will seek to end the contract over it. More trouble than it's worth, she will relent.
Threaten to move out over it, and make sure you look like you might cry. She will relent, if you use all the advice above, such as protecting the wall/floor where you keep it. She may not be aware of how valuable your bicycle is to you, so be clear that it's not a toy but a necessity, and that you will seek to end the contract over it. More trouble than it's worth, she will relent.