Spring type
Torsion vs extension, wire size and cycle rating.
01Cables
Cables run from the bottom brackets up to drums on the torsion bar. Rust at the bottom, fraying strands or slack on one side mean replacement. Cable work involves spring tension, so it is a job for a technician.
02Rollers
Steel rollers without bearings wear quickly and are loud. Nylon rollers with sealed bearings run quieter and smoother. Replacing rollers is a good time to tighten hinges and lubricate the system.
03Related work
A door that came off the track usually needs new cables or rollers; see off-track garage door repair.