Inner tubes are one of those bike related items that can be hacked in all sorts of ways. Reader Alex from Rochester, NY sent along two uses for thick tubes meant to resist thorns.
Thorn Tube Mudflap
Cut an old thorn resistant tube (they have a little more "structure") so you have about an inch of overlap on the fender and a half inch or so off the ground. Take two old spokes (cut to size) and skewer the tube as shown in the pic (three horizontal, one vertical). Keep all the pointy ends in the inside (aesthetics). This will retain good shape and give the best coverage.
Drill two small holes about a half inch in on either side of the fender, pierce tube slightly with a knife and zip tie the tube to the fender. HUGE improvement over so-called long coverage fenders. This will dramatically reduce winter slop and salt from getting to your drivetrain. Enjoy!
Thorn Tube Door Sweep
Take an old piece of lath and an old thorn resistant tube and measure/cut according to your door width. You'll likely need to cut your tube in half longwise, set this up so the thorn resistent/thick part of the tube is closest to the floor. Pre-drill four 1/4" evenly spaced holes in your lath. Use 1.25" wood screws.
Starting at one end pierce the tube with the screw already mounted through the hole in the lath. As you work from one side to the other stretch the tube slightly to keep a uniform shape. Trim excess tube at the finished end. Line up the sweep on the closed door, secure with screws and admire your upcycling project with drink in hand.