Tyre building bladders are rubber parts like turn up bladder,push over bladder and so on mounted on tyre building machines to support the green tyre building process.

Vulcanization is the process of applying pressure to the green tire in a mold in order to give it its final shape, and applying heat energy to stimulate the chemical reaction between the rubber compounds and other materials.
In this process the green tire is automatically transferred onto the lower mold bead seat, a rubber bladder is inserted into the green tire, and the mold closes while the bladder inflates. As the mold closes and is locked the bladder pressure increases so as to make the green tire flow into the mold, taking on the tread pattern and sidewall lettering engraved into the mold. The bladder is filled with a recirculating heat transfer medium, such as steam, hot water, or inert gas. At the end of cure the pressure is bled down, the mold opened, and the tire stripped out of the mold.