how long should trimmer line be

How Long Should Trimmer Line Be?

One of the most common mods that people do with their string trimmers is to remove the deflector guard. While this does have its advantages, it can also bring about some drawbacks. In line with this, we have to think about how long should trimmer line be both with the guard in place and when it has been taken off.

Most people will concern themselves with the thickness of their weed eater line and while it is true that finding the right thickness is important, there are advantages in making sure that the string trimmer line length also receives attention.

You might think that having more wire means that you have greater cutting ability but at what expense? Well, the truth is that it could be at the expense of the power of your trimmer. That’s right, your weed wacker requires a lot of power from its engine to operate and when you release too much line, this may result in the engine having to work overtime.

This may sound a little crazy, to begin with, but when you think about it, it makes sense. After all, the longer the string trimmer length, the less rpm (rotations per minute) are produced. As a result of this, your weed eaters engine will have to work doubly hard to keep producing the same degree of power. However, as it does this, less air is able to move through the cooling system and this could cause your engine to overheat. We are all familiar with the problems that this can cause so it is likely something you will want to avoid.

In addition to this, you will find that the level of vibration increases significantly when running a longer trimmer line. Manufacturers make their trimmers in a specific way and this includes being able to operate with a certain length of wire. However, many people opt for removing the guard from string trimmers allowing for lengthier wires. When the manufacturer’s intended limit is exceeded and the engine has to work harder, the vibrations naturally increase.

Length With Guard On

If you have opted to leave the weed eater guard in place then you will benefit from a much longer-lasting trimmer. This is because the engine won’t need to overwork and therefore, will have a greater lifespan.

Every trimmer is different but essentially, the length of the wire will be dictated by the guard. There should be a marker on the guard that shows you where the wire should come to. Some trimmers have a length requirement of as little as ten inches whereas others might go up to 25 inches. It is vital that you check this in your user manual. If you don’t have this, most manufacturers have an online manual for reference.

In bump models, there is normally a blade on the edge of the guard. This means that once the string is released, any excess will be automatically chopped off, leaving you with the perfect amount every time.

Length With Guard Off

Once the guard has been removed, you are free to release as much trimmer line as you see fit. However, there are drawbacks to this, as we have already discovered. That being said, we should point out that a longer wire will deliver a wider cutting area which allows you to cover more ground, and get the job done more quickly.

In terms of how long should trimmer line be when the guard is off, that’s really a personal choice. Let’s say that with the guard on, you could release 17 inches, you might want to add a few inches on top of this and go for 20”. However, you should keep in mind that the longer the wire, the less cutting power you have so while you may cover a wider area, the performance could dwindle significantly.

Safety Precautions

If you have removed the guard from your weed eater, then you will have also taken away an important safety feature. The guard serves as a way to prevent debris such as stones, pebbles and sticks, among other things, from flying up and hitting you. Without it, there is a more significant risk of injury.

For this reason, we would always advise using the correct personal protective equipment such as face shields or weed eater leg protectors when using a trimmer without a guard. However, this should also be observed when the guard is on as while it does provide a degree of protection, nothing is 100%.

You should also take the time to check the ground before starting. Doing this will give you the opportunity to remove any potential flying debris before it has even had the chance to make contact with the weed wacker.

Threading Your String Trimmer

One of the most important safety considerations when using any type of powered garden equipment is that you are using the equipment correctly. When installing a new line, there are some things you should pay special attention to. With that in mind, let’s take a look at the best way of restringing a weed wacker.

  • Make sure that you have the correct line thickness. Some models aren’t designed to work with very thick lines so you should be certain before making a purchase.
  • Before you begin, it is imperative that you ensure that the trimmer cannot turn on accidentally. Depending on the type you are using, disconnect the power or fully shut off the engine. You should also make sure that the engine is cool before you start.
  • In the trimmer head, there will be a retainer cap that can be pulled out or twisted off; this will depend on the brand, but either way, you’ll find that these are typically easy to release.
  • You can now insert the tip of the weed wacker wire into the hole on the spool.
  • There will be arrows on the trimmer that dictate which way the wire should be wound. It is very important to follow these.
  • Winding the wire around the spool should be done in horizontal lines moving side to side before beginning another layer. If you don’t do this, then there is a chance that the wire may become tangled down the line and you’ll have some serious unravelling on your hands. Furthermore, you should always make sure that the line is wound tightly otherwise excess wire may be released and this will be wasted once it is chopped off by the blade on the guard.
  • Keep winding until only around 6 inches of wire is poking out of the hole. You can then feed the line through the gap on the trimmer head and replace the cap to hold everything in place.


Many people ask the question how long should weed eater line be? While a lot of homeowners think that removing the guard to release additional line is a good idea, this could affect the performance of your trimmer. This is because the engine will have to work harder causing potential overheating and a shorter lifespan.

Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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