Brushless vs Brushed String Trimmer: What the Motor Really Changes

The brushless vs brushed string trimmer question comes down to one part: a brushed motor passes current through carbon brushes that wear down, while a brushless motor switches the current with electronics and has no brushes to wear. That is the whole mechanical difference, and it does not set swath, line size or weight.

I read the motor line of a spec table before I read the product name, a habit from years of calibrating sprayers and seed drills, where I wanted the number before the label. Below I explain how each motor works, what the makers’ claims support, which popular trimmers carry which motor and how to check a model before you buy it.

Brushless vs Brushed String Trimmer: What Actually Differs

A brushed trimmer motor uses small carbon blocks, the brushes, that press on a rotating contact called the commutator and feed current to the windings. A brushless motor drops both parts. A small controller board switches the current instead, usually guided by sensors that read where the rotor is.

The difference lives inside the motor housing. It does not decide the cutting swath, the line size, the feed system, the guard or the battery platform, and those decide most of what you feel on the lawn.

• Brushed: the brushes are a built-in wear part, and the electronics stay simple. In the models I compare below, the brushed ones sit in the budget and mid-range tiers.
• Brushless: a controller does the switching. The brushless models below run from mid-range to premium.
• Both: the head, the swath, the line and the battery pack set the real work, so judge them first.

Motor type is a battery and corded word. A gas trimmer has no electric motor, so brushless versus brushed applies only to corded and battery models, while I cover the separate battery versus gas trimmer choice in my power-source guide. The same split runs through brushless vs brushed power tools of every kind, and trimmers are one more case.

How the Two Motors Work

Both motors turn electric current into rotation with magnets and coils. They differ in how the current gets to the right coil at the right moment, and that one design choice is what the rest of this article follows.

The Brushed Motor and Its Wear Part

In a brushed motor the brushes rub on the commutator as it spins, and that contact steers the current. Rubbing wears things down. Brush wear is one of the main limits on the life of small brushed motors, and the small electric arc at each switch erodes both the brush and the commutator (1).

I think of brushes the way I thought of a sprayer nozzle: a part that wears by design, slowly and quietly, until the output drifts. A brushed trimmer is fine while that part has life left in it.

The Brushless Motor and Its Controller

A brushless motor replaces the brushes and commutator with a controller that switches the current. The controller needs to know the rotor position, and low-cost Hall-effect sensors, which sense the rotor magnets, usually supply it (2). The same review lists long operating life with no brush erosion and quiet operation among the general advantages of brushless motors over brushed ones.

The brushed vs brushless motor question is easy to answer on paper. A trimmer adds a head, a shaft, a line and a pack that all wear on their own schedule. I explain what the same motor change means in a saw in my brushless versus brushed chainsaw guide.

What a Brushless String Trimmer Gives You

A brushless string trimmer gives you one clear benefit and several claims the makers print. I separate the two before I spend money.

What Is Solid

The solid part is the missing wear part, and it is the one gain I count. I do not call a brushless trimmer maintenance free: the line, the head, the guard, the bearings and the battery all stay in service.

What Is Only Claimed

Makers like big numbers. According to WORX, its WG173 brushless motor gives “40% more power, 20% longer runtime and 10x the lifespan” compared with brushed motors, and Greenworks says the brushless motor in its 80V trimmer delivers more torque, power and life with virtually no maintenance. I put the 60V and 80V Greenworks kits head to head in my Greenworks 60V and 80V trimmers comparison.

A percentage like that describes a motor. A trimmer is a motor plus a head, a shaft, a line and a pack. I read it as the maker’s claim and check the run time printed for the actual pack instead.

Run time shows why. According to Milwaukee, its M18 2828-21 kit with a 6.0 Ah pack runs 20 minutes on low and 14 minutes on high at the 14 in. swath. Craftsman prints up to 75 minutes for its CMCST930P1 V20 kit, but with a 5.0 Ah pack, at no load, on low speed and with the 11 in. swath. The two numbers come from different packs, speeds and swaths, so they cannot be compared, and neither says anything about the motor type.

What About Noise

NIOSH sampling of landscaping crews found significantly more noise and carbon monoxide exposure when workers used fuel-powered trimmers than battery versions (3). That gap is gas against battery, and it says nothing about the motor type.

I cannot give you a decibel difference between brushed and brushless battery trimmers. I wear ear protection with either kind.

What the Motor Does Not Change

Almost everything you feel at the end of the shaft belongs to the rest of the machine. Here is what stays the same whichever motor is inside.

Swath, Line and Feed

The head decides the line. The Greenworks 40V 12 in. trimmer takes 0.065 in. line only, and its manual warns that bumping the head to advance line will damage the trimmer. The brushless Greenworks 16 in. model takes 0.095 in. line and feeds by bump, a head type I weigh against auto feed in my guide to bump feed string trimmers.

Craftsman warns that serrated or heavier line will overload the motor and cause overheating, and Milwaukee warns that other line can degrade performance or cause damage. Fit only the line the head allows, because line heavier than the manual permits can overload either motor, cause overheating and damage it. My guide shows how to read the manual for the trimmer line size to use on your head.

Swath works the same way. DeWalt’s manual says line beyond the rated swath harms performance, runtime and motor life. That is a head and guard rule, and it holds for any trimmer.

On the strip along my tree rows, the head and the guard decided how close I could work to the bark, and the motor type never entered into it. My width guide covers the right string trimmer cutting width for strips like that.

Debris and Eye Protection

A trimmer throws what it hits. In a series of 26 open-globe lawn trimmer eye injuries in Taiwan, more than half involved a foreign body inside the eye, most often metal (4). Brushed or brushless makes no difference to that. Eye protection that meets ANSI Z87.1, hearing protection, heavy long pants, long sleeves, sturdy boots and gloves go on every time, and bystanders and pets stay back at the distance the manual gives.

Cold Packs and Hot Packs

A lithium-ion cell delivers less capacity and less power below freezing because its internal resistance rises (5). The motor does not fix that. EGO lists its ST1610T for operation from 32 to 104 F, and Bosch says performance of its GRT18V-40 is limited below 32 F. On cold mornings I keep the pack indoors until I walk out to start, a workaround that costs nothing.

Greenworks says in the manual of its 80V trimmer that the motor stops from overload when the head is forced into growth, recovers when the load comes off, and that a hot battery or hot trimmer shuts off until it cools. Take that as a reason to cut in stages, whatever the motor. I cover that 80V kit in my review of the Greenworks ST80L210.

Which Trimmers Carry Which Motor

Where the manual and the product page disagree, the row says so. Here are popular models with the motor as the maker states it. I compare swath and warranty only, because weights are quoted with and without the battery and would mislead.

Read the Conflicts

The Craftsman CMCST930P1 shows why I read tables. Its product name says brushless, and the spec table on the same page says brushed. It is not in the table, and I would skip it if a confirmed motor type matters to you, until the maker settles it.

Two Greenworks models also look like a brushed vs brushless pair, and they are not. The 12 in. model has a fixed swath, 0.065 in. line and auto feed. The 16 in. model has an adjustable swath, 0.095 in. line and bump feed. With all that different, no difference in feel between them can be pinned on the motor.

Warranty Does Not Follow the Motor

The warranty column shows no pattern. The brushed Greenworks and the brushed Craftsman models carry 3 years, and so do the brushless Milwaukee, Greenworks 16 in. and WORX models, the WORX only when you register it within 30 days. The brushless Greenworks Pro 60V carries 4 years and the EGO tool 5 years. A warranty covers defects under the maker’s conditions, so read its terms and do not treat its length as a motor rating.

Some makers print nothing at all about the motor. For the WORX WG163, WG170 and WG183 and the Black+Decker 20V and 40V models, neither the manual nor the maker page states a motor type, so I do not call those trimmers brushless. I compare two of those WORX models in my WORX WG163 and WG170 comparison.

How to Check the Motor Before You Buy

Checking takes a few minutes and settles the question better than any review. Work down this list in order.

1. Find the spec table on the maker’s page and read the line named Motor. A line reading “Brushless” or “Brushed” is the answer.
2. Open the operator’s manual and find its specification table. The manual wins over the product page, and it sometimes says only the voltage.
3. Compare the product name with the table. A name such as “Brushless” with a table that says “Brushed” is a conflict, so treat the motor as unconfirmed.
4. When the maker states nothing, write the motor down as “not stated”. A marketing word on the listing is not a specification.
5. Look at the head, swath, line size, feed type and run time for your pack before you give the motor any weight. I compare nine options for different yards and budgets in my roundup of the best cordless string trimmers.

I keep the motor line on the same note as the swath and the line size, which is how I used to keep a sprayer’s flow rate next to its pressure. One number alone told me little.

Who Should Pay for Brushless

Brushed or brushless is a budget and workload question, and the honest answer is different for a quarter acre of lawn and for a long fence line. The same motor question comes up with blades, and I cover it in my guide to brushless and brushed hedge trimmers.

Brushed Is a Fair Choice When

Brushed is a fair choice for short, light jobs. Edging the house lawn after mowing is the job I know best, and a brushed trimmer in the budget or mid-range tier handles it, though I explain when to choose a string trimmer or edger in my comparison. For that kind of short, light trimming I would not pay the premium tier price for a motor type.

Brushless Makes Sense When

Brushless is worth the premium when the trimmer already fits your job on swath, line and run time for a pack you will own, and the price gap is small enough that the missing brush wear matters to you. Among the models in the table, the adjustable 14 in. or 16 in. heads and the larger swaths come with brushless motors, which is a pattern in this list and not a rule of the technology. Skip the extra cost when the reason is a promise of more runtime or power, because the run time that counts is the one printed for your pack.

The pack matters more than the motor on a long fence line or a ditch bank. Check the run time the maker prints for your pack, and buy a second pack before you pay extra for a motor type.

If you already own a battery platform, look at the bare tool its maker lists as compatible. Buy it only when its swath and line suit your job and your pack has the capacity for it, and keep to each brand’s own list of approved tools. If you are still choosing a platform, my 40V and 56V string trimmer comparison shows which battery fits which yard.

Care and Safety With Either Motor

The safety order is the same for every trimmer. It protects your hands, and no motor type changes it.

Keep the guard on, because a missing guard leaves the line too long and overloads the motor. Charge and store the pack within the temperature range in your manual, and use the maker’s charger and battery only. Never use a damaged or swollen pack.

When I clear a wrapped head, I switch off, wait for the head to stop and take the battery out, then I set the pack down away from keys, coins and other metal.

What To Take Away From the Motor Debate

Three things to remember: the missing brushes are the one solid gain of a brushless motor, the maker’s claims about runtime and life are claims, and the head, swath, line and pack decide most of the work. My tip is to read the motor line of the spec table and the manual before the product name, and to buy the pack size you need before you pay for a motor type. A buyer who knows the swath, the line and the run time of the pack already knows more than the brushless vs brushed string trimmer label on the box can tell. When you are ready to shop, I compare nine picks across power types in my list of the best overall string trimmers.

Frequently Asked Questions

What is a brushless string trimmer?

A brushless string trimmer is an electric trimmer whose motor has no carbon brushes and uses electronic commutation to switch the current instead. The spec table or the manual is the place to check which motor a model has.

Is brushless more powerful than brushed?

Brushless is not more powerful than brushed by definition, since motor type describes how the current is switched and says nothing about a power rating. Cutting performance depends on the whole tool, so compare the swath, the line size, the speed settings and the pack the maker lists.

How long do brushless motors last?

A brushless motor has no brushes to wear down, which removes one wear part from the motor. That does not set a life for the complete trimmer, since the head, shaft, bearings and pack wear on their own schedule.

What are brushless motors?

Brushless motors are electric motors that replace the brushes and commutator with an electronic controller, usually guided by Hall-effect position sensors. A product name and its specification table can disagree, so read the motor line of the specification table.

Brushed vs brushless motor: which is better?

A brushed motor is the simpler and cheaper choice for short, light jobs, and a brushless motor removes the brush wear part and suits owners who want it. Judge the whole trimmer by its swath, line, feed and run time for the pack you will use.

References

1. Sawa K, Ueno T, Nakano K, Toya K. Effects of brush spring force on brush wear and arc behaviors of small DC motor. 2023 IEEE 68th Holm Conference on Electrical Contacts (HOLM). 2023:1-6.
2. Gamazo-Real JC, Vazquez-Sanchez E, Gomez-Gil J. Position and speed control of brushless DC motors using sensorless techniques and application trends. Sensors. 2010;10(7):6901-6947.
3. Alexander BM, Graydon PS, Pena M, Feng HA, Beamer BR. Hazardous exposures and engineering controls in the landscaping services industry. Journal of Occupational and Environmental Hygiene. 2025;22(3):189-202.
4. Zhang JR, Hsieh TC, Chang FL, He MS. Lawn trimmer-related open-globe injuries in Taiwan. Retina. 2022;42(5):973-980. doi:10.1097/IAE.0000000000003402
5. Hossain Ahmed S, Kang X, Bade Shrestha SO. Effects of Temperature on Internal Resistances of Lithium-Ion Batteries. J Energy Resour Technol. 2015;137(3):031901.

Safety Note: Read your manual first. A string trimmer or brush cutter throws debris with force, so clear stones, glass and wire from the area before you cut. Wear impact-rated eye protection with side coverage that meets ANSI Z87.1, hearing protection, gloves, heavy long pants, long sleeves and sturdy slip-resistant boots (steel-toe where your manual says so). Keep people and pets at least as far away as your manual says (50 feet in some manuals, 100 feet in others), and stop if anyone comes closer. Keep the correct guard fitted, use only the cutting attachments, handles and harness the maker approves for your exact tool, and never replace trimmer line with wire. A blade can kick sideways when it hits a stump or a thick stem, so fit the handlebar and harness your manual requires for blade work, hold both handles firmly and keep secure footing. Before you clear a jam, clean the tool or change line, a blade or an attachment, switch it off, wait for all movement to stop, then remove the battery, unplug the cord or disconnect the spark plug wire. Refuel a gas model outdoors with the engine off and cool, away from flames or sparks, and move away from the fueling spot before starting, as far as your manual says (often 10 to 30 feet); never run it in a garage, shed or other closed space. For a battery model, use only the maker’s battery and charger, charge it within the temperature range in your manual and never use a damaged or swollen pack. For a corded model, use a GFCI outlet, keep the cord clear of the cutting line and avoid wet conditions.