After 18.5 years, I had a spring break on my garage door. After doing some research, I learned that the springs are designed for 10,000 cycles and I made an estimate and came up with ~ 9000+ cycles........ so I guess we wore out the spring.
This Door had 2 springs..... a right spring and a Left spring [red and blue].
After a bunch of searching, I bought the 2 springs online for a total of $ 62.31 for 2" dia x 24" long with .225" wire dia.
www.northshorecommercialdoor.com.
To install the spring, I took the 1" dia rod down. After putting the rod with new springs back up, it took a lot of trial and error adjustment on the springs before getting it set "just right".
I have 2 16" long rods that I use to turn the spring to get the spring" loaded up" to support the door weight while in use. And YES, I was carful. This is not the first time I have adjusted door springs.
Note: When opening and closing the door manually, it should require the same amount of force. If the spring is too tight or not tight enough......it will require too much force to move the door.
If the door springs are not adjusted correctly to balance the force needed...... the plastic gears in the motor will wear out.