Originally Posted by Duragrouch

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.