We stock sealed-bearing nylon rollers in the standard 2-inch and 4-inch stem lengths, which cover the large majority of doors built in the 2001 era - that's what came standard on most builder-installed doors from that period. We also carry steel rollers with sealed bearings for anyone upgrading off the original plastic, which run quieter over time and hold up better through repeated freeze-thaw cycles. What we don't stock on the truck is anything for older, non-standard track widths - narrower or wider stem gauges you sometimes find on doors from before the 1980s. That's not the housing stock out here, so it rarely comes up in Roxborough Park, but it's worth saying: if your roller stem doesn't match a standard bracket, we may need to order it, and that adds a day or two rather than same-visit. For a typical door in this neighborhood, though, the parts we carry on the truck cover the job in one trip.