In the photo below you can clearly the shoe on the right hassole blow out in the critical wear zone – under the big toe. The shoe on the left in the same area there is one good indication that the same sole blow out is about to happen. The circled area highlights a crease which indicates that the sole is waver thin. This crease occurs were the rand rubber (the side wall rubber) laps and ends under the shoe.
In the next photo we have removed the sole to show where the lapped rubber edge meets the midsole. We made one pass with the sander on the shoe on the left to demonstrate just how soon the sole was about blow out on that shoe.
Refer back to the top photo. Ideally these shoes should have been resoled no later than when presented like the shoe on the left – just a crease and not blow out. In the time between when the crease occurred and the blow out, the climber significantly increased the wear and tear on the thin rand rubber. They also risked tearing out the sole to the extent that simple resole would not be enough to get these shoes back on rock.