I checked with M-3 and when you are ready to wind the spring on the Enclosed Trailer Ramp Spring # ERS120D81 you will need to use two 1/2 inch diameter bars (of around 18 inches long). You will insert the first bar into the winding cone of the spring and pull down. The system is then designed for 10 full revolutions of the spring. It will be easier to balance the door if the spring is wound in quarter turns.
Please note that we highly recommend only installing this if you have had previous... view full answer...