String trimmer laying on grass

String Trimmers Buying Guide

A string trimmer picks up where a lawn mower leaves off, providing the finishing touches as it whisks away grass around trees and flower beds, straightens uneven edges along driveways, and trims patches of lawn your mower or tractor can't reach. What's more, you can get a capable trimmer at a good price.

Features

Even the best-kept lawn won't look its best with untrimmed walks and tall grass poking up around trees and fence posts. The latest string trimmers address lawn-grooming issues with more performance and convenience for less money. Here are the string trimmer features to consider.

Straight or curved shaft

The shaft transfers power from the engine or motor to the lines that do the cutting. Models with a straight shaft offer a longer reach, and they tend to be better for tall users and for reaching beneath bushes and other shrubs. Models with a curved shaft tend to be lighter and easier to handle.
 

Split shaft

In these models, the shaft comes apart to accept a leaf blower, edging blade, or other yard tools. Most such add-on tools didn't prove to be very effective in our tests.
 

Rotating head

On some models, the head can be swiveled to a vertical position for edging.
 

Cutting line

Most manufacturers tell you which size replacement line fits your trimmer. Line that's too thin can compromise cutting power, while line that's too thick can bog down a trimmer's engine or motor. Two lines cut more than one with each revolution and can handle heavier growth.
 

Bump-feed line advance

This feature conveniently releases line from a spool when you bump the trimmer head on the ground.
 

Fixed-head lines

Instead of a spool, more consumer trimmers are using pro-style fixed strips to help eliminate jams and tangles associated with loading new line. You simply thread in a piece at a time.
 

Carrying aid

Many heavy-duty models have a shoulder harness for easier handling.
 

Top-mounted motor

This configuration makes electric trimmers easier to handle.
 

Stop switch

This safety feature lets you stop the engine or motor quickly without moving your hands.
 

Engine type

Four-stroke gas engines tend to start more easily than two-stroke engines. And they pollute less, because they burn straight gasoline instead of a two-stroke's gas-and-oil mixture. But four-stroke trimmers are heavier than most two-stroke models. Most gas-powered trimmers run on 87-octane regular, though some brands with high engine compression recommend 89-octane fuel.
 

Centrifugal clutch

This feature allows a gas-powered trimmer to idle without spinning the line, That's safer and more convenient than when the line keeps turning. (Electric models don't spin unless you press a switch.)
 

Starting aids

Spring-assisted starting makes pulling the starter cord of a gas-powered trimmer easier, and a relatively foolproof sequence for pushing the fuel-primer bulb and engaging the choke delivers the proper fuel mixture to a cold engine for faster starts.
 

Exhaust deflector

Most gas trimmers have a deflector to aim hot exhaust gases rearward. That's important if you're left-handed.
 

Translucent fuel tank

On gas-powered models, you can see at a glance when the fuel is low.