I’ve got these thin-soled shoes that are foot shaped and I really like them, but the damn insoles creep backward in the shoe because of how I walk.
I can just take them out by what little padding they provide is quite helpful comfort & the fit of the shoe.
Is there a glue that could adhere cork to leather while remaining flexible?
There’s a glue called “shoe goo” that worked well for me to bond a rubber insole to the sole of a running shoe. The sole isn’t cork, but it’s a rough fabric that has a similar texture.
You could get some insoles that are more rigid at the back so they won’t deform. Idk about glues
If I were you - I might try a different solution: shoe inserts. I’d google and read Amazon reviews to find the best ones. But I wouldn’t buy anything from Amazon. Once I knew the brand names - I’d go to mall with a bunch of places that likely sell the inserts. As needed - I’d go to one store after another to get a friendly store clerk to let me open the pack and try them out by walking around.
I swear by “Superfeet” inserts. They’re fuckin expensive (~$50 a pair) but they last years and I can be on my feet for 10+ hours in them
