This involves application of a new pre-cured tread strip onto the prepared casing. This is only for very high quality
casings, as no new rubber is added to the tyre sidewalls. Pre-cured tread strip, cut to length, is stuck to the casing
by a thin layer of uncured rubber. This is known as cushion gum and can be bought in, or prepared on site using a
laboratory two-roll mill. The tread and cushion gum are fitted together, carefully applied to the tyre, and the air
excluded using a roller (known as stitching)