I looked further into this following bluedino's mention of TreadWright. Doing a bead to bead retreading will eliminate the issue of rubber rot due to sunlight or wear and tear.[1]
"... when we make the remolded tire we remove the existing rubber down to about 3-6mm remaining on the recycled casing. The rubber is removed from the inside bead, across the sidewall of the tire, across the tread of the tire, all the way to the outer bead. We then replace the rubber from "Bead-to-Bead" applying 6mil rubber on the sidewalls and multiple plys of rubber on the tread."
They probably do some kind of scan to determine the structural integrity of the tire structure, I imagine.
"... when we make the remolded tire we remove the existing rubber down to about 3-6mm remaining on the recycled casing. The rubber is removed from the inside bead, across the sidewall of the tire, across the tread of the tire, all the way to the outer bead. We then replace the rubber from "Bead-to-Bead" applying 6mil rubber on the sidewalls and multiple plys of rubber on the tread."
They probably do some kind of scan to determine the structural integrity of the tire structure, I imagine.
[1]https://www.treadwright.com/pages/faq