Bump Feed vs. Fixed Line

Bump it to Feed it

• A bump feed head takes its name from bumping the bottom of the trimmer against the ground so that a calibrated amount of line is fed out of the head. When the head is tapped on the ground, while the trimmer is running, an internal spring is squeezed and the whirling motion of the trimmer head causes the string to feed outward. The spool is loaded with either one or two lines, depending on the manufacturer’s design.

Bump to Save Time

• The advantage of a bump feed head is the operator can control how often the line feeds out, because string is only released when the head is tapped on the ground. There is no stopping and starting the unit to let more line out, saving time when you are trimming your yard. When it comes time to reload the spool, you can either wind new string onto the existing spool or remove it and replace it with a pre-loaded spool of string, saving even more time when you’re trimming. One downside is that the head can be damaged if bumped against the ground too hard, especially on hard surfaces such as flat rocks or sidewalks.

No Need to Wind Line

• Fixed line trimmers, also called fixed head, differ from bump feed heads because they do not use a spool system. Instead, line is cut to length or purchased pre-cut and then slid into holes on the head and held in place by grips. This method eliminates the need to wind thread on a spool, and these heads can take larger sized line than bump feed heads. String that is larger in diameter can cut heavier grass. On the downside, you must stop the trimmer each time you need more string. On some heads, the string tends to pull out when contacting wire fence or large weeds, resulting in more time replacing the string.

Right Line, Right Cut

• As summer wears on, uncut ditches or areas around outbuildings may go uncut for long periods, resulting in denser weed patches and weeds with stems that are large in diameter and hard to cut. Whether you choose a bump feed or fixed line head, match the right line with the workload. For general trimming around your lawn, choose line that is 0.085-inch diameter or smaller. For large weeds, choose a line 0.110-inch diameter or larger. Make sure the line you choose is within the manufacturer's recommendations for your brand of trimmer. Using a line that is too heavy for your machine could result in the line becoming jammed in the head.