Patented wing design keeps tire from climbing out of the head during mountingHead rotates relative to hex mount bar for improved fit with wheel rimDeep overhang design avoids raised spokes and provides additional rigidityFor first time buyers with TCX5X models with serial numbers lower than IKE721041, TCX56 models with head kit lower than VKI046785, and all TCX565, 550, 5X5, 500 models, conversion kit RP11-8-11400329 is required for install.