Late-1980s torsion systems
By the late 1980s, torsion spring systems on steel doors had mostly replaced the old extension-spring setups, and garage door openers were shifting from basic chain drives to the early screw and belt-drive units. So the truck we send out here carries torsion springs in a spread of wire sizes, steel roller and track hardware sized for that era's door openings, and the drive parts that match chain and screw-drive openers built to last through a few decades of Texas heat.
