The flywheel on our trucks is very thick and can be resurfaced usually more than once before it gets to minimum thickness. I have to ask why your are replacing it though. If your truck is stock and has less than 200k on it I doubt that it is worn out, unless it has been abused. I made the mistake of buying a new one for mine at 98k when the 5th gear fell off. Thought I might as well do the clutch at the same time. We miked the old one and it had less than 30% wear, even though I tow a very heavy trailer.