How do I know if I need extension spring or torsion spring?

If you have a one piece solid flip up door then you will always need extension spring. A sectional roll up door can have either extension springs or torsion springs. If you have a roll up door than torsion springs will either be above the garage door attached to front wall of garage.

And torsion springs can also have torsion springs at the back of the end of the track near the opener if you have one. This is called torsion to the rear. If you have extension springs on same door than the springs are at the back of door above the track and are attached to a long cable with a pulley at the front of the track where the track bends. The torsion springs are tubular and run through a metal pole and the pole runs the length of door and has cable drums at each end. Extension springs (Extension springs are found on sides of door or run along sides on top of track) stretch out when door is down and contracts to open the door.

Do not ever try to remove and replace torsion springs yourself. Suppliers don’t even sell them to general public. Sometimes you can find extension springs at retail hardware stores such as Home Depot, Ace or Lowes