Originally Posted by ronzorini
No ultimate solution, but instead of using bungee cords, you can try quick release nylon webbing straps--the kind used for backpacking. They are more durable and can be cinched down tightly.
http://www.rei.com/product/709044
The problem with the webbing straps is that they don't cinch down well when the object is rigid like a box. I just don't trust them.
Here is what they need. Something like the cargo tiedown straps, with a ratchet tightener. But regular cargo tiedown straps are too long, too bulky and too heavy for cycling applications. They have to be, because they are used to secure hundreds or thousands of pounds of cargo on trucks and airplanes.
We only need to secure at most 30-40 pounds, usually far less. So a lighter, thinnner, shorter strap with hardware that is plastic or alloy. But with a ratchet tightener that we can get uber-tight and not worry about coming loose.