Trimmer line buying guide

Trimmer line, also referred to as nylon line or strimmer cord, should be chosen to match the type of machine you have and the kind of vegetation you need to tackle. For example, do you have soft grass or long grass? Or do you perhaps need to trim back some undergrowth?

It's also important to think about how powerful your machine is, as this largely dictates the type of trimmer line you will be able to use. Finally, you'll have to determine whether you're after a trimmer line spool or a pack of individual lines.

Trimmer line sizes

Trimmer line can come in a range of shapes including round, hexagonal and even square. Whatever the shape of the trimmer line, the size of the line refers to its diameter even if the line is square. Please note that when talking about the diameter of square trimmer line, the value actually refers to one side of the square. The size of the trimmer line is one of the most important factors to consider and generally ranges from 1.2 to 4.5mm.

It's often tempting to go for a larger size than required thinking that the job will be quicker and easier or that there will be less risk of breaking the line. However, large trimmer line also requires more power.

If you choose trimmer line that is too large for your brushcutter or trimmer you risk slowing down the speed at which the engine can turn the cutting head which causes the system to 'stiffen'. In fact, a 2-stroke engine can only lubricate itself properly if it is able to turn at full speed.

The opposite is also true. If you use a trimmer line that is too thin for the engine size, you will end up with mediocre performance compared to the amount of fuel you burn. The table below sets out basic guidelines to match trimmer line to the equivalent engine capacity of a 2-stroke engine:

Line thickness, vegetation and brushcutter power

• The thinnest trimmer line (1.2 to 2mm) is designed for short grass and low-growing plants such as ray grass and clovers. This type of nylon line can only be fitted to less powerful trimmers.

• Thicker trimmer line (up to 3mm) is designed for longer grass and can be used for medium-powered trimmers or brushcutters.

• The thickest trimmer line (3mm+) is usually twisted, serrated or square-shaped and is designed for long grass and low undergrowth. This type of nylon line can only be used with the most powerful brushcutters.

Line thickness and cutting heads

A 'universal' trimmer head with a manual, semi-automatic or automatic cord feed system can only take trimmer line of up to 3mm.

A multi-line trimmer head designed for pre-cut line doesn't have a particular size limit beyond the manufacturer's recommendations.

In either case, the most important factor to consider when purchasing trimmer line is engine power.

The shape of a trimmer line refers to the form of its cross-section. A few different shapes are available depending on the type of vegetation you want to cut.

Round trimmer line

Round trimmer line is the most traditional option. This trimmer line is versatile and often comes as standard when you buy a brushcutter or trimmer. Round trimmer line offers a few advantages:

• it can be used on any brushcutter or trimmer;

• it unwinds from the spool easily;

• its round shape gives it strength and a cutting angle that never alters.

Square trimmer line

Known for its strength, square trimmer line cuts less evenly than round line – in fact, the flat side of the line tends to hack through grass rather than cut it.

That said, it does work well for rough grass cutting or clearing small areas of undergrowth. But be sure to keep this type of line far away from trees or wall render!

Star-shaped trimmer line

Star-shaped trimmer line is also known as pentagon or hexagonal line as it features five or six sides. It boasts a number of cutting edges giving it a very effective cut – any way you position it, it is poised to cut! This type of trimmer line can easily cut through long grass for a neat finish and a high precision cut. Its even cutting angle also makes it very resistant to wear.

Serrated trimmer line

Trimmer line can only be serrated if it is thick enough (3mm+) and must therefore only be used on powerful machines. These lines look a lot like saw blades and work particularly well for undergrowth.

As sharp as a saw but just as flexible as traditional nylon line, this type of trimmer line will save you having to use a brushcutter blade to cut down tough stems from plants like thistles, mugwort or brambles.

Twisted or helicoidal trimmer line

A fairly recent addition to the market, this type of trimmer line spins more easily meaning it requires less effort from the engine. This results in relatively quiet operation and a very hardwearing nylon line. Twisted line is very versatile.

One type of trimmer line is not necessarily better than another. Regular users will have their own preferences depending on the type of task being performed. For example round, flexible line or a twisted line is usually easier to use for lawns while a serrated line will be more effective on rougher grass.

Trimmer line is almost always made of nylon which is a polyamide. In fact, it is often simply referred to as 'nylon line'. However, high-performance materials can be added to this material for greater durability, flexibility and wear resistance. For example, fine aluminium particles will provide the line with better breakage resistance around the eyelet where the wire comes out. Depending on the types of materials used to make the line it might be called things like two-component, titanium and so on.

Oxo-biodegradable line is a better option for anyone hoping to protect the environment and the planet in the long term. Featuring the same characteristics as traditional nylon line, this type of trimmer line should 'only' take 7 to 10 years to break down.

Trimmer line is sold in spools or in packs of lines. Spool lines are designed to be inserted into the cutting head of a trimmer or brushcutter that winds automatically or manually.

Individual spool lines are pre-cut nylon lines that come in different lengths (e.g. 26cm, 35cm, 42cm) to be thread manually through the head.

Please note that cutting the line from spools yourself will be much less expensive than buying pre-cut trimmer line.

Trimmer line needs a bit of humidity to retain all its properties. Keep the nylon line away from sources of heat in a moist environment to ensure it stays strong. You can also moisten the line from time to time to ensure it maintains the right level of humidity.