Originally Posted by lawkd

Mox, I used to think exactly what you did, that the wear was mostly on the plates and pins, and not the rollers. BUT my own experience, at least with SRAM chains, has been contrary to that. And it's not the *outside* of the rollers that wears, I think it's the *inside* of the rollers, rubbing against the pseudo-bushings that are created by the plates. That makes sense too, because it's probably the first place where grit combines with lube to form grinding compound. If the rollers are made of softer metal than the plates, as seems to be the case with the SRAM chains, they are what will wear, on their inside surfaces. If the plates are softer, *they* will wear. If the pins are softer than the plates, the plates will wear them away like in the picture. But my chains still had pristine, perfect pins and measured at exactly 12 inches, when the rollers had worn enough to have significantly more space between them.

Of all the methods discussed above, I think that San Rensho's is best. It takes the exact measurement of the gap between adjacent rollers, which is the bottom line, regardless of what exactly creates that gap. I like gcl8a's comparison of new chain/old chain, too.