Fiberglass and vinyl garage doors are composite units, combining a steel core behind a fiberglass or vinyl skin. They have also polyurethane insulated base sections, or other type of foam insulation. These premium doors can match steel garage doors, and be a realistic imitation of wood (namely fiberglass units), but they may be more expensive than steel units.
2.3 Beware of older winding cones. These older Crawford and McKee torsion spring cones were made for 5/8" bars. Sometimes, however, the holes are too small for 5/8" bars. Whatever you do, don't use a 1/2" bar; instead, grind down a 5/8" bar to fit. I recently had a McKee spring let loose after winding because I used a 1/2" bar when my 5/8" bar wouldn't fit. Just before it let loose I was telling myself, "This is not safe." And it wasn't. The only safe way to replace these older springs is to make a winding bar for each hole of each cone.
With over 300 independently moving parts, your garage door is a deceptively complex piece of equipment. To help prevent malfunctions and break-downs, it is a good idea to occasionally perform a garage door tune-up to keep all of these parts in good working order. A regular tune-up service by a Sears professional can prevent unexpected door problems and prolong the life of your existing equipment. http://m.youtu.be/Z_eZc-kh40c