Redesigning shoes is not a project for the fainthearted. Especially it’s not a job for anyone not deep into the shoe manufacturing business. For starters, shoes take a terrible beating in use, so their construction needs to make use of various tricks for robustness and an extremely robust and strong design would not appear to lend itself to designs that can be disassembled for reuse or replacement of parts. We are fortunate however because some designers at Nike have flung themselves at the redesign process and have come up some interesting ideas See Wikipedia discussion.
The report on the Nike redesign goes through a number of innovations that made sense to Nike. There is only one which has a major impact on Zero Waste design for product reuse, as opposed to reduction of direct manufacturing waste and scrap. And it’s a lulu.
What the article suggests, is that the new design incorporated an outer sole WHICH WAS NOT IRRETRIEVABLY FASTENED TO THE UPPER SOLE. This is an astounding breakthrough, given the mechanical forces and constant abrasion which afflicts the outer sole. What appears to have been done, is to design the lower surface of the upper sole and the upper surface of the outer sole so that they strongly interlock with each other. Presumably this interlocking attachment will survive the stresses of walking and running. However, any form of interlock can also, by the proper use of tools and knowledge, become separated. This allows for contemplation of the repair of the most heavily worn part of the shoe, the outer sole.
Once the outer sole is available as a separate piece, it might be possible to add material to it to repair the worn parts, in the same way that tires are recapped. Of course the polymeric material out of which the sole is made must be selected to allow for this possibility, back when the sole was manufactured. At present, this constraint is nowhere in the design.
This observation doesn’t end the question of shoe reuse and repair. The uppers, the tongue, the laces, the tie holes and more also wear out. But it’s a start.