I snapped a belt driving on a newly paved road with some gravel and tar. I'm sure it was a piece of gravel that tried to go through one of the sprockets. At 2000 miles I had a small piece of gravel punch a hole through the original belt so I replaced it.
The belt was still working so I coiled it up and jammed it inside the frame under the seat as a spare. When the replacement belt snapped, I coasted into a driveway and decided to try to install the spare. It was really easy to do by removing the rear fender and unplugging the taillight wire. The replacement belt can be installed by passing it between the tire and hugger fender then on the inside of the rear sprocket and over the front sprocket. I didn't mess with the axle nut, I just rolled the belt on by rolling the bike backwards. Yes, I know this is not recommended and also that you are not supposed to coil up the belts but this is an old belt with a hole in it. I was back on the road in about a half an hour and rode home 30 miles in rain mode to limit strain on the belt. There are very few tools needed to do this. See the photos to see the belt storage, tools used and broken belt.
This worked perfectly and got me home where I could properly replace with a new belt.