Robot mower leaving uncut strips: what overlap and cutting-width specs say

Cut width is the smallest number on the spec sheet

Across the mowers we publish pages for, published cutting width runs from 7.1 in to 15.7 in. That is a spread of more than a factor of two, and it is the single figure that decides how many passes a machine has to plan and land correctly to cover a given lawn. A 7.1 in swath needs roughly twice as many adjacent passes as a 15.7 in swath over the same ground, which is twice as many opportunities for a positioning error to leave a ribbon behind.

Two of those figures carry a measurement basis that a bare comparison hides. Sunseeker publishes 14 in for the X7, but that is the combined width of dual cutting discs, three blades on each of two discs, not the swath of a single blade disc. Dreame publishes a 40 cm (15.7 in) mowing width for the A3 AWD Pro 3500 in its spec table, with marketing copy on the same page rounding to 15.8 in for dual blades. Worx publishes 7.9 in (200 mm) as cutting diameter for the Landroid Vision WR208 in the official owner's manual, and does not show it on the web spec table at all.

Nothing in that list is a defect. A narrow disc is a deliberate trade against weight, battery draw and manoeuvrability, and the small-yard machines in this set are narrow for good reasons. It just means that a complaint about strips on a 7.1 in machine and the same complaint on a 15.7 in machine are not the same engineering problem.

• Segway Navimow i110N: 7.1 in (US spec page publishes inches directly).
• Mammotion YUKA mini 2 1000H: 7.5 in.
• Worx Landroid Vision WR208: 7.9 in (200 mm), published in the owner's manual, not the web spec table.
• Ecovacs GOAT O1000 RTK: 8.66 in.
• Segway Navimow X350: 9.3 in, with systematic mowing on a 6-blade cutting disk.
• Husqvarna Automower 420 iQ: 9.4 in, three pivoting razor blades.
• Sunseeker X7: 14 in, and that is the combined width of two discs, not one.
• Mammotion LUBA 3 AWD 3000 and Dreame A3 AWD Pro 3500: 15.7 in (400 mm).
• Discontinued but still published: EcoFlow Blade 10.2 in, Mammotion LUBA 2 AWD 3000HX 15.7 in.

Systematic and adjacent-pass navigation are not the same job

How a mower plans the next pass decides whether a positioning error shows as a stripe or gets absorbed. Husqvarna documents both approaches for Automower and is unusually explicit about the trade. Its published account of selectable, or systematic, mowing describes the mower building a cutting path from a pre-selected direction, the lawn's shape and known obstacles, then cutting along the calculated paths while keeping a slight offset at each mowing session to prevent track marks and ensure full coverage, finishing with a perimeter pass that it states removes any uncut grass along the boundary and obstacles. It offers three patterns: parallel, chequerboard at 90 degrees to the previous session, and triangle at 60 degrees.

Husqvarna also publishes when not to use it. Systematic mowing is described as most suitable for flat, open areas with few obstacles, while irregular mowing is described as ideal for lawns with slopes, complex work areas and areas with many obstacles such as trampolines or flower beds, specifically to achieve an even mowing effect as the lawn is cut uniformly from all directions. That is the maker telling you that a complex lawn on a systematic pattern is the configuration most likely to leave visible strips. Its stated payoff for systematic mowing is capacity, not finish: it claims an increase in work area capacity of at least 50 percent on typical residential lawns and up to 100 percent in open areas such as football pitches. Our spec record for the Automower 420 iQ carries the same split from the product page, with area capacity published as 0.5 acre for irregular areas and 1 acre with systematic mowing.

Mammotion documents four selectable cutting path modes for the LUBA 3 AWD 3000 under Mow, Settings and Cutting Path Mode: Perimeter Laps Only, which mows only the lawn edges; Zigzag, described as classic striped lines; Chess Board Path, described as a crisscross pattern for a dense, even finish; and Adaptive Zigzag Path, in which the robot automatically adjusts the path for efficiency. Segway publishes systematic mowing on a 6-blade cutting disk for the Navimow X350. None of the three publishes the line spacing or overlap percentage that any of these patterns actually uses.

The documented causes of missed areas, maker by maker

Segway publishes the longest cause list of the three, in a Navimow Academy article on missing areas dated 09 July 2026. Its named causes are mapping issues, including forgotten areas when creating multiple zones and, notably, sharp turns of less than 90 degrees where it states the mower will leave some area while trying to make a smooth turn; internet issues, where it says an unstable connection can leave the map only partly loaded so the mower misses the areas that did not load; inaccurate positioning from antenna or charging station placement; non-grass areas such as stone paths and utility holes that the mower treats as obstacles and reroutes around; long grass or weeds, which it says the mower may also read as obstacles; a dirty camera lens or LiDAR sensor causing false obstacle detection; narrow passages, where it says multi-directional obstacle detection reads close walls as obstacles and the mower returns before it enters; hidden objects in the grass; and animal detection. On the last of these it adds a caveat worth keeping: an area skipped because of a bird or an animal is not permanently missed, and it states the area is not missed until mowing progress is 100 percent.

Segway's published fixes are correspondingly specific. Edit the map rather than remap, keeping mapped turns greater than 90 degrees and drawing in straight lines. Split a narrow passage into two separate zones, or set a VisionFence-Off zone, which it describes as an area where the mower does not sense obstacles and mows like a blind mower, with the explicit warning to use it only in safe and predictable areas, never where children and pets roam, and to keep it as small as possible. Place the antenna at least 6.6 ft from trees and buildings, or on a wall or roof. Keep the charging station at least 6.6 ft from trees, house walls and fences with at least 1.6 ft clearance on the left and right and 6.5 ft at the front. Clean the camera lens and LiDAR regularly.

Husqvarna documents one gap that is stated as a hard geometric rule rather than a symptom. In its systematic mowing article it describes the mower stopping in front of an unexpected object, continuing the planned pattern around it, and returning afterwards to complete the area behind it, then states plainly that any areas less than 1 metre or 3.3 feet between an unexpected obstacle and the virtual boundary will remain uncut. That is a published, unrecoverable strip: a garden chair left a metre from the fence produces one by design. It adds two more pattern rules: for EdgeCut mowers, a parallel pattern running in only one direction can leave edges uncut while chequerboard and triangle cover edges from multiple angles, and for the 435X AWD NERA it states uncut grass can occur in sharp corners under systematic patterns because of the mower's size and the space it needs to turn. It also notes that a mowing session is interrupted if the work area is not completed within 72 hours, and that if the lawn is not fully cut after a session the remedy is to extend the scheduled hours.

Husqvarna's camera troubleshooting adds a fourth mechanism for vision-navigated machines: a dirty or blocked camera glass produces the messages Camera lens blocked or No object detection available, heavy rain produces Camera lens wet and a pause, and on several NERA models an Object avoidance setting lets owners choose Continue mowing, which it warns may cause the mower to collide with objects, or Pause mowing until visibility is restored. Mammotion exposes the equivalent lever differently, as an Obstacle Detection Mode with three levels, where Sensitive is described as increasing sensitivity to both standard obstacles and non-grassy areas such as pavement and gravel. A machine set to Sensitive on a lawn with bare patches has been told to treat those patches as things to avoid.

• Husqvarna: less than 1 m (3.3 ft) between an unexpected obstacle and the virtual boundary stays uncut.
• Husqvarna: a one-direction parallel pattern can leave edges uncut; alternating patterns cover edges from multiple angles.
• Husqvarna: a work area not completed within 72 hours interrupts the session.
• Segway: mapped turns sharper than 90 degrees leave area behind during the turn.
• Segway: narrow passages can be refused because close walls read as obstacles; split the passage into zones or use a VisionFence-Off zone.
• Segway: long grass and weeds can be read as obstacles, so an overgrown patch is skipped rather than cut.
• Segway and Husqvarna both: a dirty camera or LiDAR causes false obstacle detection and reroutes.

Slip is the third mechanism, and it has its own numbers

A wheel that turns without moving the machine puts the next pass in the wrong place, which produces a strip that no amount of pattern tuning will fix. Segway's Navimow Academy article on slipping, dated 05 August 2026, puts wet grass first and states plainly that if you are using the mower on wet slopes then slipping is perfectly normal. Its published waiting periods are concrete: after morning dew, wait until 10 am; after a gentle sprinkle, 4 to 6 hours; after a drizzle, 4 to 6 hours; after heavy rain, at least 24 hours. Its second cause is an uneven surface, with bumps and dips reducing speed and increasing the chance of slips, and its remedy is to level the slope. Its third is that some Navimow models carry a Traction Control System that it describes as dynamically adjusting wheel torque to prevent slipping on low-traction lawns, enabled in the app.

Mammotion says the same thing in its LUBA 3 pre-mowing guidance: mowing in the rain can make the grass stick on the robot and cause slipping, and the robot should not be operated in standing water or in heavy rain. Husqvarna approaches it from the pattern side, warning that on slopes a chequerboard pattern can send the mower across the slope side to side, potentially causing wear on the lawn or causing the lawn mower to slip, and recommending mowing straight up the slope, or setting the pattern at 45 degrees to it.

The published slope ratings tell you where the risk lives, and the boundary figure is the one that matters for strips because that is where edge passes run. The Navimow i110N is published at 30 percent (17 degrees) maximum slope ability but only 10 percent (6 degrees) maximum slope at the boundary. The Navimow X350 is published at 50 percent (27 degrees) with 25 percent (14 degrees) at the boundary, and Segway's slipping article repeats the same 50 percent and 25 percent split for the X3 series. The Automower 420 iQ is published at 45 percent maximum slope performance inside the installation with slope at the boundary limited to 15 percent. The GOAT O1000 RTK is published at 45 percent (24 degrees) for the work area with a separate lower limit of 17 percent along virtual boundaries. Mammotion's LUBA 3 manual publishes 80 percent (38.6 degrees) inside the task area and 40 percent (21.8 degrees) at the edge. A boundary that runs across a bank steeper than the second number in each of those pairs is outside the published envelope, and a strip along it is the expected result rather than a fault. Our guide to slope ratings sets out how each maker measures these.

What the documentation tells you to change

Built only from the published instructions above. Nothing here is our own diagnosis, and each item belongs to the maker named beside it.

The ordering is deliberate: the free changes come first, and the ones that require a remap come last.

• Clear the strip and inspect it. Remove stones, twigs, toys and hoses, and cut any patch that is taller than the surrounding lawn down to the same height, because both Segway and Husqvarna document long grass and small objects as obstacle triggers.
• Clean the camera and the LiDAR. Husqvarna specifies checking the camera glass for leaves and slugs, rinsing with running water and drying with a soft cloth; Segway says to clean the camera lens and LiDAR regularly.
• Check the pattern against the lawn. Husqvarna publishes systematic mowing as suited to flat, open areas and irregular mowing as suited to slopes, complex areas and obstacle-heavy lawns.
• Alternate the cutting direction. Husqvarna recommends this for optimal area coverage and grass health, and notes a one-direction parallel pattern can leave edges uncut.
• Extend the schedule. Husqvarna states that if the lawn is not fully cut after a session, the remedy is more scheduled hours, and that a work area not completed in 72 hours interrupts the session.
• Mow dry. Segway publishes concrete waiting periods after dew, sprinkling, drizzle and heavy rain; Mammotion prohibits operation in standing water and heavy rain.
• Move furniture away from boundaries. Husqvarna publishes that anything less than 1 m (3.3 ft) from an unexpected obstacle to the virtual boundary stays uncut.
• Edit the map rather than rebuild it. Segway says to keep mapped turns greater than 90 degrees and to draw in straight lines, and to split a narrow passage into two zones.
• Reassess antenna and charging station placement. Segway publishes at least 6.6 ft from trees, walls and fences for both, plus 1.6 ft side and 6.5 ft front clearance for the station.

Where the record has gaps

Three gaps are worth stating so this reads as no more complete than it is. First and largest: not one maker behind the mowers we publish pages for publishes a path overlap figure. Cutting width is published everywhere, and pattern names are published almost everywhere, but the spacing between adjacent passes, the overlap percentage, and the positioning tolerance the planner assumes are published nowhere we could find. That is the number that would actually let you predict striping from a spec sheet, and it does not exist in public. Husqvarna comes closest by describing a slight offset at each mowing session to prevent track marks, without quantifying the offset.

Second, Husqvarna's deepest coverage documentation does not list the iQ series. Its systematic mowing article names the NERA, EPOS, Aspire and commercial models it applies to, and the 410 iQ, 420 iQ, 435 iQ AWD and 440 iQ appear nowhere in that list, even though the 420 iQ product page publishes a separate area capacity for systematic mowing. The 1 metre obstacle-to-boundary rule, the 72 hour interruption and the pattern guidance are all published inside that article. Whether they transfer to an iQ machine is not stated either way, and we are not going to assume it.

Third, Segway's missed-areas and slipping articles are published as Navimow Academy blog posts rather than as support articles tied to a model, and the slipping article's model list covers the X4, H2, X3, i2 LiDAR and i2 AWD rather than the i110N and X350 we publish pages for. The X3 figures it quotes match our X350 record, but the i-series figures it quotes belong to i2 models. For the underlying spec comparison across the set, see our guides to cutting height and width and passage width, and for what makers leave out generally, what yard robot makers do not publish.