A process and a plant for producing tyres for vehicle wheels are described. Building of a crown structure of the tyre includes building a crossed belt structure on a substantially cylindrical first forming drum, transferring the crossed belt structure from the first forming drum to an annular holding member, positioning a second forming drum in a radially inner position with respect to the annular holding member, transferring the crossed belt structure from the annular holding member to the second forming drum by radially expanding the second forming drum until it is brought into contact with the crossed belt structure so as to toroidally shape the crossed belt structure, and depositing at least one zero degrees belt layer on the second forming drum in a radially outer position with respect to the toroidally-shaped crossed belt structure.

A method for building belt assemblies for tyres for vehicle wheels is described. The method includes building a crossed belt structure on a forming drum. Depending on the type of tyre to be produced, the method selects whether to build a belt assembly having a cylindrical shaping or a belt assembly having a toroidal shaping. In order to build a belt assembly having a cylindrical shaping, zero degrees belt layer is deposited on the forming drum in a radially outer position with respect to the crossed belt structure. In order to build a belt assembly having a toroidal shaping, the crossed belt structure is picked up from the forming drum. The crossed belt structure is then toroidally shaped and transferred onto another forming drum. A zero degrees belt layer is then deposited on the other forming drum in a radially outer position with respect to the toroidally shaped crossed belt structure.

A method for building belt assemblies for tyres for vehicle wheels is described. The method includes building a crossed belt structure on a forming drum. Depending on the type of tyre to be produced, the method selects whether to build a belt assembly having a cylindrical shaping or a belt assembly having a toroidal shaping. In order to build a belt assembly having a cylindrical shaping, a zero degrees belt layer is deposited on the forming drum in a radially outer position with respect to the crossed belt structure. In order to build a belt assembly having a toroidal shaping, the crossed belt structure is picked up from the forming drum. The crossed belt structure is then toroidally shaped and transferred onto another forming drum. A zero degrees belt layer is then deposited on the other forming drum in a radially outer position with respect to the toroidally shaped crossed belt structure.

A process and a plant for producing tyres for vehicle wheels are described. Building of a crown structure of the tyre includes building a crossed belt structure on a substantially cylindrical first forming drum, transferring the crossed belt structure from the first forming drum to an annular holding member, positioning a second forming drum in a radially inner position with respect to the annular holding member, transferring the crossed belt structure from the annular holding member to the second forming drum by radially expanding the second forming drum until it is brought into contact with the crossed belt structure so as to toroidally shape the crossed belt structure, and depositing at least one zero degrees belt layer on the second forming drum in a radially outer position with respect to the toroidally-shaped crossed belt structure.

A plant for producing tyres for vehicle wheels is described. The plant includes a building line configured to build a crown structure. The building line includes a building device configured to build a belt assembly. The building device includes a trolley, a first forming drum, a second forming drum, a first working area including a belt building device, a second working area downstream from the first working area including a depositing device, a first service area downstream from the second working area including a stationary annular holding member, and a second service area downstream from the first service area including a first support member.