This isn't something I was wanting to do but I had a blow out on the rear tire yesterday so, here I am. This morning I disconnected the derailer, disconnected the ,motor cable and loosened the axel nuts and removed the brakes. At this point, I expected the rim to just lift off the frame. No such luck... after applying some penetrating oil and a few good tugs, it seems something is still holding the rim to the frame. Any suggestions would be appreciated. Pictures for reference.