How to replace strimmer line and spools

Before you start

Remove the battery or unplug the strimmer. For a petrol strimmer, stop the engine and disconnect the spark plug lead. Check the manual for the line diameter your head takes, usually between 1.2 mm and 2.4 mm on garden strimmers, and whether it uses single or dual line.

• The correct line diameter, or a pre-wound spool
• Gloves
• Scissors or side cutters
• Your manual for the winding direction

Strimmer line sizes explained →

Fitting a pre-wound spool

This is the easiest option and the one many battery strimmers are designed for.

1. 1

   Press the tabs on the head cover and lift it off

2. 2

   Lift out the empty spool and its spring, if fitted

3. 3

   Clean grass and dirt from inside the head

4. 4

   Fit the spring and new spool, feeding the line ends through the eyelets

5. 5

   Refit the cover until it clicks

6. 6

   Trim any excess line with the cutter on the guard

Rewinding a spool by hand

Rewinding is cheaper than buying pre-wound spools. Cut the length of line your manual recommends. For a dual line spool, the line is usually either folded in half and hooked into a central slot, or wound as two separate lengths in two channels.

1. 1

   Remove the empty spool

2. 2

   Hook or insert the line end into the anchor slot

3. 3

   Wind tightly and evenly in the direction of the arrow on the spool

4. 4

   Do not overfill; stop below the rim

5. 5

   Clip the ends into the notches on the spool rim

6. 6

   Refit the spool, feeding the ends through the eyelets, and refit the cover

Note:Winding in the wrong direction stops the line feeding. Always follow the arrow on the spool.

Loading a bump feed head

Some heads, including many on higher voltage strimmers, can be loaded without taking them apart. You line up arrows on the head with the eyelets, push a length of line straight through until it is centred, then twist the head knob to wind it in. It is quick once you have done it once. The EGO Powerload system winds the line in automatically with a button press.

Getting the line to feed

Most strimmers feed line automatically or by tapping the head on the ground while running. If line does not come out, it may be wound too loosely, crossed over itself, welded together by heat or the wrong diameter. Soaking nylon line in water overnight before winding is a traditional tip some gardeners use to keep it supple; check what your maker recommends.

If the line keeps snapping short, see why strimmer line keeps breaking.

Replacing the whole head

If the head is cracked, the eyelets are worn through or the bump knob is damaged, replace the head. Heads are often specific to a brand and model. Some universal heads are sold, but check the thread and fitting before buying. Our explainer on strimmer line sizes and shapes covers compatibility questions.

Choosing between spools and line on a reel

Pre-wound spools are quick and tidy, which makes them popular with people who strim only occasionally. Line on a reel is cheaper per metre and lets you choose the shape, such as round, twisted or square, within the diameter your head takes. If you strim a lot, rewinding from a reel soon becomes second nature.

Whatever you choose, store spare line out of direct sun, because nylon becomes brittle with age and heat. Brittle line snaps more often and feeds poorly.

If you are choosing a new strimmer, the head design is worth a look. Bump feed heads that load without dismantling, like those on many higher voltage models in our cordless strimmer guide, make line changes far less fiddly.

Frequently asked questions

Which way do you wind strimmer line? In the direction of the arrow on the spool. Winding the wrong way stops it feeding.

How much line goes on a strimmer spool? Check the manual. Overfilling stops the line feeding properly.

Can I use thicker line than recommended? No. Thicker line can jam the head and strain the motor. Use the diameter in the manual.

Are pre-wound spools worth it? They save time and fiddling, but rewinding from a reel is cheaper over a season.