Segway Navimow X4 Series Review

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The X4 series is Segway’s new flagship for big residential lawns. It sits above the X3 series in Navimow’s range, and it’s the first Navimow with all-wheel drive at this size. It’s sold through Navimow’s own store and, per PCWorld, at Lowe’s, The Home Depot and Walmart.

I went through Navimow’s product pages and buying guide, plus long reviews from PCWorld, Techaeris and 9to5Toys. I haven’t owned or tested an X4 myself. I run a metal and composites workshop and keep my own lawn with EGO battery tools, so I paid close attention to the drive, the blades and the battery, but everything here is based on the published specs and reviews.

The X4 line-up: X430 vs X450

Navimow currently sells two X4 models in the US.

Navimow’s pages and the Techaeris review say the two share the same chassis, all-wheel drive, cutting deck and navigation. The only listed differences are rated area and the length of free cellular service. So everything below applies to both.

Which one? If your lawn is under an acre and fairly simple, the X430 is enough. If you’re near an acre with lots of beds, trees and slopes, or above an acre, the X450 gives you headroom for about $500.

Key specs

Specs are from Navimow’s X4 product page, the X450 page and Navimow’s buying guide. Size and weight are from PCWorld’s review and Techaeris.

Navigation: Network RTK and 360° vision

Like every Navimow, the X4 works without a buried perimeter wire. It finds its position with RTK, satellite positioning corrected to a few centimeters, and draws its boundaries from a map you make in the app.

Network RTK: often no antenna

Older RTK mowers need a reference antenna on a pole or a roof. The X4 uses Network RTK, which gets corrections over the cellular network. Navimow includes it at no extra cost, and Techaeris describes the service as free for life. PCWorld found it activated automatically in its area.

Where the network service isn’t available, you use the GNSS antenna included in the box. PCWorld notes that means assembling a mast, finding a spot on the ground and keeping a clear view of the sky.

Cameras for the hard parts

On top of RTK, the X4 runs 360° camera vision with VSLAM and VIO. That does two jobs.

1. It keeps tracking position when satellite signal drops under trees or close to the house.
2. It spots obstacles. Navimow says it detects more than 200 types. 9to5Toys lists dogs, toys, lawn chairs, pots and hoses among the things it recognized.

Two caveats came up in reviews. 9to5Toys’ X430 didn’t detect a test pile of dog poop hidden in the grass, and the mower treated the reviewer as an obstacle and skipped areas around them. Techaeris warns that dense tree canopy or tall structures can still block satellite signal, so placement of the dock and antenna matters.

For a deeper explanation of RTK, cameras and LiDAR, see how robot mowers work.

Cutting: 17 inches, 0.75 to 4 inches

The X4 cuts a 17-inch strip with two discs and 12 pivoting blades. Pivoting blades fold back when they hit something hard instead of chipping or bending. Techaeris says they folded back on rocks and roots, which is what I’d want to see as someone who sharpens and repairs blades.

Cutting height goes from 0.75 to 4 inches in quarter-inch steps. That covers short warm-season lawns like Bermuda and zoysia and tall cool-season lawns like tall fescue. Navimow also lists up to 8 cutting layers for tall grass, meaning it can step the height down over several passes.

Reviewers were happy with the cut. Techaeris called it clean and consistent. 9to5Toys found that on a hilly, uneven yard, the 4-inch setting did little on tall grass and that heights around 2 to 2.75 inches gave the most even result there. That’s normal for uneven ground: a higher cut shows every bump.

The X4 mulches clippings. There’s no bag. Frequent mowing keeps the clippings small, which is better for the lawn anyway. My guide on how to mow a lawn explains the one-third rule and the right height for your grass.

Slopes and rough yards

This is the X4’s strongest point.

• 84% (40°) slope rating, the steepest in Navimow’s current range.
• Four-wheel drive with high-torque hub motors and dual suspension.
• Xero-Turn articulated steering. Instead of skidding to turn like most robot mowers, it steers its wheels, which should reduce torn turf on turns.
• Steps over obstacles up to 2.8 inches.

PCWorld didn’t test the full 84% claim, but noted the X430 stayed inside a narrow drop-off boundary where a smaller Navimow slipped twice. 9to5Toys ran it on a hilly yard and said edge awareness near a curb was strong.

One caution from 9to5Toys: on wet ground, the X430 can dig up grass. That’s true of any 64-lb machine with driven wheels. Let soggy lawns dry before mowing.

If slopes are your main concern, compare it with others in best robot mowers for hills and slopes.

Battery and charging

Navimow lists about 110 minutes per charge and a 90-minute or faster recharge from a 224 W charger. It covers up to 9,600 sq ft per charge. PCWorld cites about 5,382 sq ft per hour.

Runtime drops on steep slopes, in mud and thick grass, and in hot weather, as Techaeris points out. When the battery runs low, the mower goes home, charges and resumes.

There’s a good battery-care feature: you can cap charging at 80% or 90%. Lithium-ion packs last longer when they aren’t held at 100% all the time, and I’d set it to 90% for the season.

9to5Toys expects the battery to need replacing after about 3 to 5 years. It’s replaceable, at extra cost.

Setup

Plan on an afternoon.

Unboxing. The box is large and heavy. 9to5Toys used a yard cart and Navimow recommends two people to lift the mower out. Techaeris also notes there are no proper carrying handles.

Dock placement. 9to5Toys says Navimow’s guide warns against placing the dock against the house, under trees or under homemade shelters, which can block satellite signal. Navimow sells its own Garage X shelter.

Firmware. PCWorld’s mower ran two updates that added about 20 minutes.

Mapping. You have two choices.

• Auto-mapping: the mower drives the edges itself. Good for flat, clearly edged lawns. PCWorld says Navimow advises against it where your lawn blends into a neighbor’s, around pools or near drop-offs.
• Manual mapping: you steer the mower around the edge with the app. 9to5Toys used this on a complicated yard and said there’s a learning curve; the first attempt was redone.

Tip from 9to5Toys: keep the boundary a bit away from fences and raised concrete edges. Its X430 got stuck where a raised edge met lower grass. You’ll trim those edges by hand anyway.

App, connectivity and security

The Navimow app handles maps, schedules, zones (up to 120), no-go areas and per-zone settings. EdgeSense handles border mowing, and there’s a Doodle mode that mows patterns and letters into the lawn, which is a fun party trick.

Connectivity is Wi-Fi, Bluetooth and built-in 4G. The 4G lets you control the mower and get alerts away from home. Connect+ is free for 1 year on the X430 and 2 years on the X450, then $32.90 a year.

Security features include GPS tracking, Apple Find My, a lift alarm and PIN protection. It works with Alexa, Google Home and Home Assistant.

Reviewers liked the app overall. PCWorld found it intuitive, with stop and home controls easy to reach. Techaeris found it a little sensitive on small phone screens.

Noise and weather

Navimow lists under 68 dB(A) in lab, no-load conditions. PCWorld cites 60 dB(A), and the Techaeris reviewer reported roughly 60 dB in use. Either way, it’s much quieter than a gas mower.

The mower and charging station are rated IP66. PCWorld says the power supply and camera are IP67. A rain sensor sends the mower home when it starts to rain. 9to5Toys doesn’t recommend night mowing, because vision is reduced in the dark.

What reviewers liked and disliked

Liked:

• Strong navigation on complicated lawns (PCWorld).
• Excellent, consistent cut and good blade protection (Techaeris).
• Climbs rough and steep ground with confidence (all three).
• No wire and often no antenna.
• Quiet in use.

Disliked:

• Price is high for small or simple yards.
• About 64 lb and bulky; two people to unbox, no carrying handles.
• Signal can drop under heavy tree canopy.
• Setup, firmware updates and mapping take time.
• Camera lenses need regular cleaning.
• Tall weeds may need a second pass.

How it compares

Navimow X3 series (X330, X350). Navimow’s older big-lawn line costs a bit less (the X330 is around $2,300 for 1 acre) and runs longer per charge, but it’s rated for only 50% (27°) slopes and doesn’t have all-wheel drive. Choose an X3 only if your lawn is mostly flat.

Husqvarna Automower 420 iQ. Also rated for 1 acre, quieter and much lighter at 38 lb, with a 4-year warranty and dealer support. But it costs more, cuts only 9.4 inches and is rated for 45% slopes. See my Navimow vs Husqvarna comparison.

Mammotion LUBA 3 AWD 5000. Rated for 1.25 acres and 80% slopes, with 360° LiDAR that should help under trees, and about 41 lb. Its standard version cuts only 1 to 2.7 inches, and its deck is a little narrower. See Navimow vs Mammotion.

Who should buy the X4?

Buy the X430 if:

• Your lawn is around half an acre to 1 acre.
• You have slopes, banks or bumpy ground.
• You have trees, beds and kids’ stuff to work around.
• You want one mower that covers 0.75 to 4 inches.

Buy the X450 if: your lawn is over an acre, or close to an acre with a complex layout.

Skip it if: your yard is small and flat. Navimow’s own i-series costs much less for lawns under a third of an acre, and you’ll find more options in best budget robot mowers.

My verdict

The Navimow X4 is the robot mower I’d shortlist first for a big, hilly US lawn. All-wheel drive, an 84% slope rating, a 17-inch deck, a full 0.75 to 4-inch height range and Network RTK make it a very complete package for the price.

The trade-offs are real. It’s heavy and bulky, the warranty is shorter than Husqvarna’s, and like every camera-based mower it needs clean lenses and decent light. But for a lawn of about an acre with hills, I don’t see a better value right now. Want to see it against the rest of the field? Check my best robot lawn mowers guide.