How To Replace Strimmer Wire
Swapping the spool on our WORX cordless strimmer took a few simple steps and the same method works on most other models.
The short answer
To replace strimmer wire, switch off and remove the battery or plug, then unclip or unbolt the cap and take out the old spool, noting which way it sits. Fit a pre-wound spool, or wind new line tightly onto the old one following the arrow on the spool, thread the ends through the eyelets, refit the cap and test that the line feeds out.
Strimmer line has a habit of running out halfway round the garden, and it's always at the far end from the shed. Getting it going again isn't difficult, and corded, cordless and petrol strimmers all follow much the same routine. The photos below come from changing the line on our own WORX WG163 cordless strimmer.
Before you touch the head, switch the strimmer off and remove the battery, unplug it from the mains, or pull the spark plug cap off a petrol model. It only takes a second and stops the head spinning while your fingers are in it.
Pre-Wound Spool Or New Line On The Old Spool
There are two ways to put new line in. You can buy a ready-wound replacement spool and simply swap it in, or buy line on a reel and wind it onto your existing spool. We pay the extra for pre-wound spools, like the one on the right in the photo below, as the winding is done for you and done properly. Rewinding the old spool costs less, so it's the way to go if you're watching the pennies and don't mind a fiddly job.
If you rewind your own, check the direction markings on the spool before you start and wind the line the same way. Wrap it tightly and evenly, with no twists or crossed loops, because loose winding is the main reason line jams and refuses to feed out. Use the line diameter your strimmer's manual specifies, as thicker line won't feed through the eyelets properly.
On a double-line strimmer, each half of the spool takes its own length. Once it's wound, clip the ends into the notches on the spool so they don't unravel while you fit it.
How To Replace Strimmer Wire Step By Step
1. Work Out How The Spool Is Held On
Look at the strimmer head to see how the cap and spool are fixed. Most cordless and lighter strimmers use a push-fit cap with clips on either side, while heavier petrol and commercial strimmers have a bolt or knob that has to be undone with a spanner.
Our WORX WG163 uses a simple push fitting, so getting the cap off to reach the spool took no tools at all.
2. Take Out The Old Spool
Remove the cap and lift out the old spool. Note which way round it sits as it comes out, because the new one has to go back the same way. A quick photo on your phone saves any guesswork later.
With the spool out, clear any grass and dirt packed in behind it. It's not essential, but a clean housing lets the new spool turn freely and feed line properly.
3. Wind New Line Or Grab A Pre-Wound Spool
If you're reusing the old spool, wind the new line onto it now, following the direction arrow and keeping it tight. If you're using a pre-wound spool, there's nothing to do at this stage.
4. Fit The Spool And Thread The Line
Drop the spool back into the head the same way round as the old one. It should click into place and sit firmly with no wobble. On models like ours, the end of the line then needs threading out through the eyelet in the side of the head, as in the photo below.
Refit the cap until it clicks, or tighten the bolt on a heavier model.
5. Test The New Line
Put the battery back in or plug the strimmer back in and give it a short run on some long grass. Check the line feeds out when you tap or trigger it. If it won't, take the spool back out and check the line isn't crossed over inside and that the spool is the right way round.
Stopping Strimmer Line Snapping And Jamming
Line that breaks off constantly or won't feed out is nearly always down to one of a few causes. Keep these in mind and you'll be changing spools less:
- Winding: Loose or crossed line binds on the spool, so wind it tight and even every time.
- Line size: The wrong diameter jams in the eyelets or snaps early, so stick to the size in the manual.
- Old line: Line left in a hot shed dries out and turns brittle, so store spare reels somewhere cool.
- Hard edges: Strimming tight against walls, fences and paving wears line down fast, so let the tip do the cutting.
A dirty head causes problems too, so knock out the packed grass after each session as you would when servicing a petrol lawnmower.
Changing Strimmer Line Without The Fuss
Replacing strimmer wire takes a few minutes once you know how your model's head comes apart, and a pre-wound spool makes it quicker still. How long each spool lasts comes down mostly to how much edging you do against walls and paving, so if your garden has plenty of hard edges, keep a spare in the shed.
If your strimmer is past saving, our pick of the best cordless strimmers is the place to start, and a garden multi-tool with a strimmer head is worth a look if you also need to tackle hedges. For the main lawn, pair it with one of the best electric lawn mowers.
Your Questions Answered
Which way do you wind strimmer line onto a spool?
Wind strimmer line onto a spool in the direction of the arrow printed or moulded on the spool itself. Winding it the wrong way means the line won't feed out when the head spins. If there's no arrow, check the manual, and keep the line tight and even with no crossed loops as you go.
Why does my strimmer line keep breaking?
Strimmer line keeps breaking when it's old and brittle, the wrong diameter for the strimmer, or being pushed against walls, fences and paving. Line stored in a hot shed dries out and snaps easily. Use the size in the manual, keep spare line somewhere cool and let the tip of the line do the cutting.
Can you use any strimmer line in any strimmer?
You can't use just any strimmer line, because each strimmer is designed for a specific line diameter, and many cordless models only take their own brand's spools. Line that's too thick jams in the eyelets and strains the motor, while line that's too thin snaps quickly. Check the manual or the old spool for the right size.
Is it cheaper to rewind a strimmer spool yourself?
Rewinding a strimmer spool yourself is cheaper than buying pre-wound spools, as a reel of line refills the same spool many times. The trade-off is time and fiddliness, and badly wound line jams. Pre-wound spools cost more each but drop straight in, which is why we use them on our own strimmer.
Is a pre-wound spool worth paying extra for?
For us it is. A pre-wound spool drops straight in with the line already wound tight and even, and loose winding is the main reason line jams. Rewinding your own costs less per refill, so it makes sense on a tight budget, as long as you're happy taking your time over the winding.
Do I need tools to change the spool on the WORX WG163?
No, the cap on the WORX WG163 is a push fit, and we had it off by hand. That's typical of lighter cordless strimmers. Heavier petrol and commercial machines hold the spool on with a bolt or knob instead, so on those you'll need a spanner to hand.
Is it safe to change strimmer line with the battery still in?
No, always take the battery out before your fingers go near the head. A knocked trigger with the battery in will spin the head straight away. The same goes for other types, so unplug a corded strimmer and pull the spark plug cap off a petrol one. The battery only goes back in for the test run.
What should I do if the new line won't feed out?
Pull the spool out again and look at two things, whether it went back in the right way round and whether the line has crossed over itself inside. Crossed or loose winding is the main culprit, so rewind it tight and even if needed. If both look fine, check the line diameter against your manual, as line that's too thick jams in the eyelets.
Archie is our gardening specialist. He started out as an apprentice at a gardening firm, built up his own knowledge from there and now writes most of our garden content.