Give me a stiff... inner sole.

So I’ve been riding in my Vans “fixies” a fair bit lately, and occasionally in the Gabe Morford Half Cabs and I’ve found the stiffer sole in those shoes is amazing compared to the regular inner sole in regular Vans Era’s. Does anyone know of a thin but stiff inner sole I can put in my other Era’s to stiffen them up? Or a DIY way? You can’t remove the inner sole in Vans, so it has to be reasonably comfortable.

Orthoheel (Orthaheel?), the green ones. A good bit stiffer than most but you can still walk in 'em - get ‘em from chemists and sporting goods. I use ‘em to stiffen up me wadin’ boots when I’m out tormentin’ high-country trout.