The solid rectangular tyre has a simple shape, good casting processability, easy quality assurance, and long service life. Rotary dryer has a relatively small diameter than the kiln, so the disadvantage that the solid rectangular tyre wastes more material than the box-shape tyre is not obvious, therefore the current rotary dryers almost all use solid rectangular tyres. 
Installation of rotary dryer tyre:

The rotary dryer tyre ring is looped on the cylinder body, and the backing pad is sandwiched between the tyre and the cylinder body. The gap between the backing pad and the tyre is 1-2 mm, so as to facilitate installation and adapt to the thermal expansion of the cylinder body. There are two types of pad, one is a saddle pad, the other is a welding pad. Rotary dryer saddle pad, using cast steel material. The inner and outer arcs are machined, and each clearance needs to be equal or similar. The saddle is provided with shoulders and staggered to position the tyre axially. This type of structure requires large processing and assembly work, and drilling on the cylinder will weaken the strength of dryer cylinder, so the welding pads are adopted by many dryer manufacturer.
About rotary dryer tyre made by CHAENG:

CHAENG, as a professional steel castings manufacturer, is experienced in producing steel casting tyre for rotary dryer and rotary kiln according to customers’ drawings and requirements to match the machines very well. Excellent product quality makes CHAENG rotary kiln tyre sold to Henan, Guangxi, Zhejiang and other provinces, and also to many well-known overseas enterprises in Italy, Turkey, Chicago, Kazakhstan and others.