Long time owner, first time poster, with odd question
My dad had a single speed 10 speed sized bike that he modified the frame to accept two pipe unions so he could seperate the bike in 2 and put it in the trunk of his dart. He only used it once when he ran out of gas, 15 miles from the nearest gas station.
On a more practical note...
@jaws had an OEM trailer hitch. He might still have it!