When choosing a trimmer line, take into account the power of the trimmer, for which the line is needed. Very often customers think – the thicker the line, the longer it will serve, the less it will wear out and break, but they don’t take into account the air resistance of the line when it’s spinning. Trimmers cut grass at around 8000-10000 rpm. If the diameter of a line is increased by even 0.5 mm, the air resistance increases so significantly that trimmers with insufficient power may overheat, meaning expensive repairs. If you’re working with a trimmer line that’s too thick, the speed of the trimmer also decreases significantly, thus the grass is not cut “sharply”, but rather “bluntly”, which results in longer working hours than usual.
| Trimmer power/engine volume | Trimmer line diameter |
|---|---|
| Electric trimmers 0,6kW-1,2Kw | 1,3mm-2,00mm |
| 20cm3-25cm3 | 2,0mm-2,4mm |
| 25 cm3 _40cm3 | 2,4mm-2,7mm |
| 40 cm3 _50cm3 | 2,7mm-3,0mm |
| ≤ 50cm3 | 3,0mm-3,5mm |
| Walk-behind trimmers (e.g., McCULLOCH MWT420) | 4,3mm-6,0mm |
Selecting a line by its profile – the market offers a very wide range of trimmer lines with different profiles – there are round, twisted, extruded and even serrated lines.
- The traditional – round lines – are universal lines and they cost less compared to other types of lines (extruded, reinforced etc.).
- Star trimmer line – its sharp edges provide smoother cutting of blades of grass, thus the lawn looks better and the grass turns yellow less. These lines also slightly reduce the load of the trimmer engine, thus saving its resources.
- Reinforced lines – manufacturers often add aluminium “chips” of some other material during the production of these lines, thereby increasing the service life and reducing the breakage.
- Lines with a graphite core – customers often incorrectly believe that the core of this line consists of a metal wire. On the contrary, it is a material that is even more flexible and softer, thus also making the line more flexible and softer, as well as its ends become frayed less and break less frequently.
- Twined lines – these lines are the “quietest” of all the trimmer lines. I have to admit that if you’re working with a trimmer, which has an internal combustion engine, this advantage seems insignificant (the noise is loud anyway), but if you’re working long hours every day, you will appreciate this feature. This sound difference will be more noticeable with electric trimmers.
- Lines with serrated teeth – these lines are designed for work with very high-powered trimmers and brush cutters (engine volume over 50cm3). Working with these lines requires a special trimmer head. This line can be used not only for mowing overgrown and thick grass, but also raspberry bushes, sagebrush, etc.
Trimmer lines are made of different materials – both high-quality (and thus more expensive such as polypropylene FP6) and lower quality polypropylene, and even with impurities such as low-quality polyethylene, thereby reducing production costs. Low-grade material has a lower wear resistance, it is more fragile and has a lower heat resistance. In the case of intensive work, it melts and gets stuck in the trimmer head, which complicates and prolongs the work.
There have been cases when there’s a metal wire wrapped in the trimmer head, but it is very dangerous, because as the metal wire hits rocks and other obstacles, its ends get broken off and at a large trimmer speed they turn into microscopic “bullets” that can dig into the legs.
Line storage – line should be stored in a cool and humid place. Often a line is stored in a container with water so that it does not lose its physical properties. By allowing the line to dry out, it will break frequently during mowing, it will be difficult to wrap it on the trimmer head etc. For this reason, it is recommended to purchase trimmer line for one full season.