The Ryobi CS30 trimmer uses a double track line spool instead of a single line. This helps to make quick work of your lawn trimming needs. Over time the line requires replacement just like any other trimmer. Ryobi recommends using replacement .080 filament line when restringing the spool. Stringing a Ryobi CS30 is a bit different than many other types, because you do not need to tie a knot in the end of the line where it initially hooks into the spool.
Disconnect the Ryobi CS30 spark plug wire from the spark plug. If possible, place the trimmer on a work table with the trimmer head hanging over the side of the table. Place the trimmer on its right side with the fuel tank pointing up if no work table is available.
Hold the trimmer spool with one hand and turn the spool retainer counterclockwise with your other hand. The spool retainer is on the center of the trimmer spool.
Pull the spool away from the trimmer head, leaving the spring on the top of the spool in place. Hold the spool and remove any remaining line. It might be necessary to scrape the line off the spool with a flat-head screwdriver if it has melted slightly.
Cut two 9-foot pieces of string from the stock trimmer string roll with a pair of scissors or utility knife. Insert one end of one piece of string into the anchor hole on the upper track of the spool. The anchor hole holds the end of the string securely.
Wrap the string counterclockwise evenly around the upper track of the spool. Maintain tension on the string as you wrap it around the spool. Once you have six inches of string left, slide the end into the closest upper slot of the spool.
Insert the end of the second string into the anchor hole on the lower track of the spool. Wrap the string counterclockwise around the lower track just as you did the upper track. Once there is only six inches remaining, slide the end of the string into the nearest slot on the bottom of the spool.
Place the trimmer string spool back into the housing with the spring side first. Guide the two ends of the string through the eyelet holes on the housing. Thread the spool retainer over the spool until it is hand tight.
Pull the two strings with your fingers sharply to disengage them from the slots. Push down on the spool retainer while pulling the strings to ensure the spool is installed correctly. Place the wire back over the spark plug.