Greenworks Commercial Optimus String Trimmer Review: A Legit Gas Replacement?

Greenworks Commercial has been steadily raising the bar for battery-powered OPE, and the Optimus ST161 string trimmer represents one of the company’s key handheld tools to replace gas. On paper, it checks all the right boxes. While it certainly looks promising, we’ve learned over the years that the real test happens when you put the trimmer in thick grass and let it eat.

With that in mind, we got one in for some hands-on testing and evaluation to see how it compares to other models on the market. Is this the right fit for your crew? Let’s find out!

READ
Best Battery-Powered String Trimmer Head-to-Head Review 2026

Greenworks Commercial Optimus String Trimmer Performance

Speed and Cutting Power

At its heart, the ST161 houses a brushless motor that delivers 1.6kW of continuous power and is rated as equivalent to a 36cc gas-powered string trimmer. The cutting head maintains a constant 5,500 RPM at the top end, putting it firmly in the Pro category and giving it the muscle to tackle heavy grass, weeds, and roadside overgrowth.

This trimmer sports a wide 17-inch cutting swath, which makes quick work of larger patches of grass. Unlike many trimmers, the ST161 does not feature an adjustable line cutter. Moreover, Greenworks tells us that this trimmer can hold up to 34 feet of 0.095-inch trimmer line. I’m sure you could use a 0.105-inch line in a pinch, but the overall line capacity and runtime will be affected. Given our experience, the 0.095-inch line worked flawlessly, even during heavy-duty applications.

Speed Control Modes

Greenworks equipped the ST161 with three speed settings and a variable-speed trigger. Speeds range from 4,500 RPM all the way up to 5,500 RPM. This range gives you the flexibility to conserve battery life during light maintenance trimming or unleash maximum power when you’re cutting through dense vegetation. It’s a simple feature, but one that can make a meaningful difference over the course of a full workday.

Runtime

Greenworks estimates up to 55 minutes of runtime using the recommended 4.0Ah battery. As with any string trimmer, actual runtime depends heavily on grass density, line size, and the speed setting you’re using.

During our hands-on testing, this trimmer ran for just shy of 30 minutes on high speed. Keep in mind, manufacturer runtime tests are usually conducted at the lowest speed setting, so this disparity isn’t too surprising.

While our runtime was a little lower, it’s still a respectable figure for a commercial-grade trimmer performing at this power level. Even better, the included dual-port charger can recharge batteries quickly, minimizing downtime between tasks.

Cutting to the Chase

When it comes to string trimmers, testing is a little difficult because these tools really only have one job. With that in mind, we had to get a little creative to test the actual cutting speed.

To evaluate cutting speed, we built a dedicated test rig using three layers of Vigoro reed fencing stretched across an 8-foot section. This material closely mimics the tall, stalky vegetation we often come across in overgrown sections, while providing better consistency than if we were to try and find a “close enough” section of lawn to work in.

We run the test at least twice and rate it based on the fastest time.

The Greenworks ST161 completed the two runs with an average time of 7.40 seconds—the fastest overall time in the group of trimmers we recently tested. To put that in perspective, the slowest model we tested (Ridgid RO1201VNM) completed the same test with an average time of 24.12 seconds! Moreover, Greenworks even managed to unseat our previous champion, the Makita 40V max XGT GRU07, which posted an average time of 9.0 seconds.

Another aspect we gauged was the overall vibration level; we rated all of our trimmers on a scale of 1 to 5, with 5 being the highest level. Here, Greenworks earned a 3. The vibration level wasn’t off the charts, but we were certainly aware of our hands after some extended trimming sessions. Granted, this is pretty subjective, especially if you’re a Pro switching over from gas-powered equipment.

Overall, this trimmer is clearly in the top tier of cutting performance as a serious Pro-grade option and definitely earned some major kudos from our testing team.

Greenworks Commercial Optimus String Trimmer Design Notes

Size and Weight

The ST161 weighs approximately 11.3 pounds as a bare tool and 15.7 pounds with the recommended Core300 battery installed. That puts it on the heavier side compared to many residential models, but that’s hardly surprising considering the commercial-grade gearbox, larger motor, and heavy-duty drivetrain.

The good news is that Greenworks paid close attention to balance. The top-mounted motor and compact gearbox help distribute weight throughout the tool, but there is a slight rearward bias when you hold the trimmer by the front handle.

While this sounds like a con, I actually found it helped while I was working and improved the overall maneuverability.

Moreover, this trimmer features a lanyard hook so you can attach a shoulder strap, further reducing fatigue during extended trimming sessions.

Trimmer Head

One feature that immediately catches my attention is the Load n’ Go trimmer head. Reloading line is one of those chores nobody enjoys, so any system that speeds up the process is worth talking about.

The spool accommodates up to 34 feet of 0.095-inch line, which should keep interruptions to a minimum during a normal day. Greenworks claims reloads can be completed in roughly a minute (and we believe them), making this a practical setup for Professional crews who need to stay productive.

Reverse Function

A standout feature on this trimmer is the reverse mode. If you’ve ever wrapped vines, fencing wire, or stubborn weeds around a trimmer head, you already know why this matters.

Simply activate reverse mode and feather the trigger; this will allow you to clear jams without disassembling the trimmer head or manually unwinding debris. It’s one of those features you may not use every day, but when you need it, you’ll be glad it’s there.

Durability

Greenworks clearly designed the ST161 with Pros in mind. It features a solid driveshaft, a magnesium base plate on the motor housing, an aluminum shaft, and a commercial-grade gearbox that’s rated for over 1,000 hours of operation before maintenance. Those are the kinds of details landscape crews look for when evaluating long-term durability.

From my personal observations, this trimmer is built to last. This becomes even more evident when you compare the ST161 to a residential trimmer. There is almost no flex in the shaft, the forward grip feels solid, and while it is a little heavy, this trimmer feels very stout.

Greenworks Commercial Optimus String Trimmer Price

The ST161 is available in three configurations: one bare tool and two kit options. The bare tool retails for $599.99, and the main difference between the kits is the kitted battery. One kit lists for $649.99 and comes with Greenworks’ standard 82V 4.0Ah battery, while the other kit sells for $949.99 and includes Greenworks’ new Core300 4.0Ah battery.

For most folks, the standard battery will do the trick and deliver solid performance. However, serious Pros should consider spending the extra cash for the new batteries, which offer superior power output and cooling.

Should You Buy It?

The Greenworks Commercial ST161 feels like exactly what a Professional battery-powered string trimmer should be. It delivered legitimate high-end gas-replacement power during our testing and proved that battery-powered OPE can stand up to the best. Not to mention, the feature set absolutely screams Pro.

But let’s be honest…as amazing as this trimmer is, it’s not cheap. The price tag on the ST161 puts it out of contention for most homeowners, unless you’re planning to maintain some serious acreage. However, for Pros, I believe the gas and maintenance savings will help start to help your bottom line faster than you think.

Bottom line, if you’re a Professional crew that’s looking to move away from gas-powered equipment, the Greenworks Optimus lineup deserves a spot near the top of your shortlist. And when you consider how well the Optimus line as a whole can replace gas equipment, it’s even more compelling.

Specs

• Model: Greenworks Commercial ST161
• Power Source: Greenworks 82V battery
• No-Load Speed: 4,500 / 5,000 / 5,500 RPM
• Estimated Runtime: 55 min. (with 4.0Ah battery)
• Max Power Output: 1.6kW (2.14 HP)
• Gas Equivalence: 36cc
• Cutting Swath: 17 in.
• Feed Style: Bump
• Line Capacity: 34 ft. (0.095 in.)
• Max Line Diameter: 0.095 in.
• Shaft Material: Aluminum
• Total Length: 72.5 in.
• Weight: 11.3 lbs (bare tool), 15.7 lbs (with Core300 4.0Ah battery)