What is the difference between the A and C type pinions for model GSR-R racks.
The entire surface of the A type pinion has been face hardened. Only the teeth of the C type pinion have been face hardened. For this reason, when the C type is used by the customer, hole diameters can be changed, key grooves can be machined and other additional machining can be performed as desired. However, additional machining with the A type is impossible because surface hardness has been increased by face hardening. Contact THK for details about the hardness of materials.