There is a MUP down right by the arch. If you're on the same road that goes in front of the arch right along the river go north or towards the TWA Dome and you will hit the riverfront trail right in front of the old Laclede power building. They do rent bikes during the summer not sure about now or the type. I think it's more of a cruiser type rental, but if you ask like the previous poster on the other forum you will probably find something.