The cryo rings do not get so hard that they do not wear in, but they do get harde enough to reduce overall wear, transferring a bit more of the "wear in" (the initial "shaving" of the rough un-evenities) on the cylinder walls. The process is the same, except now the walls are broken in more so thantherings themselves. Cryoing is good because it leaves the rings less worn and less prone to blow by, since they will wear less in the future and be less succeptible to cracking/breaking due to the improved internal structure.
sil80
