Shipping a bike

[OakLeaf]

We own a box and get about six trips before they are toast.

Wow.

I just counted, my Thule box has nine FedEx flights on it in the past four years, and really no sign of wear on the hard parts (including wheels) or the straps, handles and buckles. I expect the foam is about halfway to needing replacement - which I think is as much a function of time as it is of use - and it's just plain sheets of foam rubber the size of the box, no molded or pre-cut holes, very inexpensive. I actually cut up an old convoluted-foam mattress topper to supplement the foam that came with the box.

Why do you think your box is wearing out so quickly?