Add a stiffer arch supporting insole and improve that issue.. ..
I kept repairing the Birkenstocks i got in he 70's , last resole I had them use denser rubber..
On my bikr rours I got a shoe shop ti add stiff nylon in a shoe and birkenstock insoles
resoled them .. they fit loose, and being stiff were like penny loafers with the heel of my foot coming out as I walked..
more recently , close out, got SiDi touring shoes but that is not offered any more , maybe in UK/EU? IDK
Sandals? hand made?
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