I know that most of us use a nylon strap as a way to keep our doors from swinging around and slamming against the side of the trailer. I was trying to figure out where to get the nylon strap when it occurred to me that a car seat belt would work perfectly. They come in a variety of colors so you can color coordinate to your trailer. They are quite strong, have a nice weave, and every junkyard has hundreds of them to choose from.
For those of you building multiple tears, one seatbelt will do a bunch of trailers!

I had a friend pick up a tan seatbelt out of the junkyard when he was there. (They didn't even charge him for the piece) I cut off a few feet and threw it in the washing machine to clean it up. Once dry, I cut one piece for each door. I folded each end over for a double thickness where the screws go through. A big squirt of hot glue held it folded over while I finished the strap. Next I heated a piece of clothes hanger over the stove and burned two screw holes in each end. Lastly, I used some stainless steel screws and upholstery washers to hold it in place.

Just one way to do it.
Joanne