Commercial doors are not a bigger version of a residential door - the springs carry more load, the track is heavier gauge, and a torsion spring under full tension on a wide commercial door can put someone in the hospital if it lets go while unwound by hand. We tell every caller the same thing: don't touch the spring system yourself, full stop. Cable replacement, track alignment, and anything involving the torsion bar is a two-person job with the right winding bars, not a Saturday project. Where a business owner can safely do some of the work themselves is the low-risk stuff - clearing track of debris, checking that photo-eye sensors aren't blocked, tightening loose hardware on the header bracket. That's the honest limit of DIY on a commercial door: cosmetic and maintenance tasks, yes; anything that stores spring energy, no.