In a grinding device, first, an eddy-current-sensor detects a distance from the eddy-current-sensor to an outer peripheral surface of a belt layer while a tire to be retreaded held by a pair of half rims is caused to rotate. One such system comprises a decoder adapted to decode a received transmission frame using a decoding scheme, a channel assessment unit for sensing channel characteristics, and a tuning unit for adjusting the decoding scheme based, at least in part, on channel characteristics sensed by the channel assessment unit. High pressure gas causes forward movement of the recoil piston thereby generating a force opposing the recoil generated upon firing.