Robot mower buying guide
How to choose a robot mower for slopes
The maximum slope number is a screening tool. Traction, surface condition, slope direction, transitions, and nearby hazards decide whether a mower is truly suitable.
Quick answer
Measure the steepest sustained mowing area and the transitions into it, convert the result to the same unit used by the manufacturer, and leave margin below the published maximum. Favor traction, braking, and drive layouts suited to the terrain, then check wet-grass guidance and boundary setbacks near drop-offs.
Percent grade is not degrees
Slope percent is rise divided by horizontal run, multiplied by 100. Degrees measure the angle. A 45 percent grade is about 24 degrees, not 45 degrees. Compare like with like, and use a reliable level or measurement method rather than estimating by sight.
Measure the steepest part the mower must actually traverse, including short ramps, ditch edges, and transitions. A published maximum may assume dry, firm grass and a straight climb rather than wet turf, side-hill travel, or a turn at the limit.
Traction is more than four-wheel drive
Driven wheels, tire design, weight distribution, articulation, ground clearance, cutting-deck movement, braking, and control software all affect hill behavior. Four-wheel drive can add capability, but it does not make every steep or slippery area safe.
Look for official guidance on maximum slope at the boundary as well as inside the work area. The allowed grade near a perimeter can be lower because stopping or turning room is limited.
Protect dangerous downhill edges
Water, retaining walls, roads, steps, and open drop-offs deserve a physical risk assessment. Virtual mapping and obstacle sensing are useful features, not substitutes for the manufacturer's required setbacks or barriers where a navigation error could cause damage or injury.
Plan drainage and avoid mowing when the surface is too wet. Repeated wheel slip can damage turf even when the mower eventually completes the route.
Buy with operating margin
A mower rated exactly at your measured maximum leaves little room for measurement error, wet conditions, side slopes, or surface change. Shortlist models above the requirement, then compare credible owner reports from similarly shaped properties.
Buyer checklist
- Steepest grade measured, not estimated
- Percent and degrees converted correctly
- Internal-slope and boundary-slope limits both checked
- Wet grass, loose soil, and side-hill travel considered
- Traction, braking, clearance, and drive layout compared
- Water, roads, walls, and drop-offs physically protected
Apply the guide to real models
Open the source-backed catalog with a useful starting filter, then verify the exact model page and linked documentation.
Open the filtered catalog