For this job we carry both steel and nylon rollers, since older track profiles sometimes need the steel ones to seat right. We stock replacement track sections in the common lengths, end brackets, center brackets, and the lag hardware to reset a bracket into solid framing rather than just re-driving the same holes. Cable is on the truck too, along with the drums it seats on, because a door that's off-track from a jumped cable needs that fixed before the track alignment matters at all. We carry lubricant meant for door hardware, not general-purpose grease, since the wrong lubricant on old rollers just attracts grit and makes the next jam worse. What we don't carry is a match for every discontinued track profile - some older hardware from this era isn't made anymore, and if a section needs a specific match we don't have on hand, that's a return trip rather than a same-visit fix. We'd rather tell you that up front than pretend every truck carries every part.