Originally Posted by
wschruba
FYI, most narrow-wide chainrings need replacement if you have changed a cassette due to wear. If you get two cassettes out of one chainring, that is considered reasonably good.
Their cumulative wear usually results in noisy operation, or in more extreme cases, a chain not releasing smoothly...same as it ever was. Component wear manifests as skipping on the rear, and typically as failure-to-release on the front, unless it's simply good and roached.
Hmm... thinking why... narrow-wides have every other teeth wider, so more resistant to wear, the narrow teeth are standard width. So my guess is this results in different speed of wear between narrow and wide, resulting in length mismatch at a very local level. Maybe not, as the wide teeth will still be pushing on the same width roller (and not the inner sideplates, hopefully), so perhaps the roller contact point is the exact same width as the narrow teeth. Curiouser and curiouser.