It is important to check the winding of your current spring to avoid buying the wrong one.
Garage door spring winding direction.
Right wound left wound or both.
Usually you will have two springs on your door which will be color coded.
Replacement of torsion springs is among the most common garage door spring repairs performed by companies that specialize in garage doors.
Most of the time the end on the right hand wind is red and the left and wind is black as you can see on the graphic below.
Each spring used in this manner has a particular wind direction.
Black winding cone torsion springs are used on the right side of the door and red winding cone torsion springs are used on the left side of the door when viewing the door from the inside looking out.
Right hand winding springs wind in a clockwise manner with the end wire on the right while left hand winding springs go anticlockwise with their end wire on the left.
Basically door springs can either wind to the left or to the right.
How to determine wind direction.
In most cases you can determine the wind of your garage door torsion spring by using the color coded system on the cones at the end of the spring.