Most houses in Lomira went up around 1991, a full generation newer than the 1970 median that describes the rest of our service area. That later build date means most doors here are the multi-panel steel type that came standard with factory nylon rollers, not the older one-piece or heavier sectional hardware you'd find on a 1960s house. Nylon rollers are quieter and don't need oiling, but they age out on a schedule: the nylon sleeve dries and hairline-cracks over roughly 10 to 15 years of cycles, and once it cracks, it starts shedding chips into the track.
Our winters push that timeline along. This part of Wisconsin sits in a severe cold climate band, and cold-hardened nylon cracks faster under load than it does in a mild-winter market. If your door's rollers are original to a house built in the early '90s, they're at or past the age where cracking is normal, not a sign anything else went wrong.