I use a strap-on bow quiver made by Great Northern and had the lower rubber strap break the other day. Not having access to a replacement strap (does GN even sell them?) I cut a strip from an old bike innertube as a replacement. Works great, and if anything the bow actually seems a little quieter than before, maybe because the tube is stretchier and the few extra wraps around the bow holds the quiver tighter. Anyway, its an easy emergency fix that you can make in the field with a few extra biketube straps stored in your gear bag. And they can also double as bungees if you have gear needing to be tied down.