Even the best lawn trimmers will eventually need new string. Doing this kind of maintenance can be intimidating for some people, but replacing the string on a trimmer is not difficult. With a little help, it won’t be long before you’re out trimming your lawn once more.

Method1

Changing the Line on a Single-Line Trimmer

lines for single line trimmer

1
Prepare the line. The length and width of line you need varies based on your trimmer. If you purchase the wrong width of line, the trimmer will not work correctly, so don’t waste your money by simply guessing at the hardware store. If you are not sure what size line your trimmer uses, check online—the manufacturer’s website often has instructions, and if not the customer service department should be able to help you.The length to which the line should be cut also varies, from around 10’ to 25’. If you are not sure, err on the side of too long; you can always cut it shorter later.
2
Make sure your trimmer’s engine is turned off. If it has a gearbox, make sure it is cooled down. This will help prevent accidents.
3
Remove the retaining cap from the trimmer head. This will probably involve either unscrewing it, pressing one or multiple tabs, or a combination of the two.Some models use different mechanisms for removing the spool. These should be designed to be relatively intuitive, but contact your trimmer’s manufacturer if you are having trouble figuring it out.
4
Locate the starter hole in the spool. Insert the tip of the trimmer line, and wind in the direction of the arrows.Wrap the line in neat, straight rows, to prevent jams later on. When there are about 5” or 6” of line remaining, snap it into the retainer on the spool to hold it in place.
5
Line up the retainer with the slot on the outside of the head. Replace the spool into the trimmer head. Remove the line from the retainer, and pull it through the slot to make sure it is feeding smoothly.Reattach the retaining cap.
Method2

Changing the Line on a Double-Line Trimmer

double line trimmer

1
Prepare the line. The length and width of line you need varies based on your trimmer.If you purchase the wrong width of line, the trimmer will not work correctly, so don’t waste your money by simply guessing at the hardware store. If you are not sure what size line your trimmer uses, check online—the manufacturer’s website often has instructions, and if not the customer service department should be able to help you.The length to which the line should be cut also varies, from around 10’ to 25’.If you are not sure, err on the side of too long; you can always cut it shorter later.
2
Make sure your trimmer’s engine is turned off. If it has a gearbox, make sure it is cooled down. This will help prevent accidents.
3
Remove the retaining cap from the trimmer head. This will probably involve either unscrewing it, pressing one or multiple tabs, or a combination of the two.Some models use different mechanisms for removing the spool. These should be designed to be relatively intuitive, but contact your trimmer’s manufacturer if you are having trouble figuring it out.
4
Locate the starter holes in the spool. Insert the tip of the first length of trimmer line into one starter hole, and wind in the direction of the arrows.Wrap the line in neat, straight rows, to prevent jams later on. When there are about 5” or 6” of line remaining, snap it into the retainer on the spool to hold it in place.Repeat this process with the second line. At this point, the line ends should be at opposite sides of the spool, to match the eyelets on the outside of the trimmer head.
5
Remove the lines from the retainers. Thread them through the eyelets on the outside of the trimmer head. Replace the spool into the trimmer head, and pull the lines through the slot to make sure they are feeding smoothly.Reattach the retaining cap.
Method3

Changing the Line on a Speed-Feed Trimmer

speed-Feed trimmer

1
Prepare the line. The length and width of line you need varies based on your trimmer. If you purchase the wrong width of line, the trimmer will not work correctly, so don’t waste your money by simply guessing at the hardware store. If you are not sure what size line your trimmer uses, check online—the manufacturer’s website often has instructions, and if not the customer service department should be able to help you.The length to which the lines should be cut also varies, from around 10’ to 25’.If you are not sure, err on the side of too long; you can always cut it shorter later. Both lines should be cut to the same length.
2
Make sure your trimmer’s engine is turned off. If it has a gearbox, make sure it is cooled down. This will help prevent accidents.
3
Rotate the cap so the arrows align with the eyelets. You should be able to see light through the head when you look through the eyelets.
4
Thread the end of the trimmer line through one eyelet. It should come through the eyelet on the other side of the trimmer head. Hold the ends together and pull to make both sides even. Twist the head clockwise until 5” or 6” of line are exposed.