Best Robotic Lawn Mowers for Hills and Slopes in 2021

Hills and slopes can be an important consideration if your yard or garden has uneven or undulating areas. One of the most common questions I get when it comes to robotic lawnmowers is “But can it mow on hills”?

The good news is that most robotic lawn mowers can deal with hills and slopes. However, there are a wide variety of factors, including the number of wheels, wheel design, traction, weight distribution, power output and battery life, to bear in mind when it comes to determining just how capable the particular model that you may have your eye on is when it comes to dealing with those inclines.

The best robotic lawn mowers for mowing on slopes are:

Model	Mowing gradient
WORX Landroid M 20V WR140	up to 35%
WORX Landroid M 20V WR143	up to 35%
WORX Landroid L 20V WR150	up to 35%
WORX Landroid L 20V WR153	up to 35%
HUSQVARNA Automower 310	up to 45%
REDBACK POWER RM24	up to 50%
HUSQVARNA 435X AWD	up to 70%

This article aims to provide a thorough examination of all the factors that should be considered when determining the best robotic lawn mower for dealing with hills and slopes in 2021. If you have a yard or garden with inclines that need to be mowed, read on to find out more!

Do Robotic Lawn Mowers Actually Work on Hills?

If you have been wondering whether those nifty robotic lawn mowers that more and more people are delegating all their repetitive lawn mowing tasks to can handle your garden’s hills, fear not — I’m here to hopefully set your mind at ease and help you make a decision based on your own needs with some solid data.

As mentioned, most robotic lawn mowers can mow on slopes, at least to some extent, but the degree of the incline on which they can operate depends on the brand, design and its features.

Below is an exhaustive list of the features that determine the maximum operating inclines of robotic lawn mowers.

What to Look for in a Robotic Lawn Mower for Hills

Consider these factors when it comes to robotic lawn mowers that will be used to operate on hills.

Four Wheels As Opposed to Three Wheels

The number of wheels on a robotic lawn mower has a lot to do with the maximum slope upon which it can operate. Four wheels provide better balance and thus make it easier for robotic lawn mowers to mow on hills and inclines.

Wheel Design and Traction on the Drive Wheels

The design of the wheels on your robotic lawn mower can also make a big difference when it comes to its ability to mow on inclines. Some designs are specifically aimed at stability and traction of the drive wheels, whereas others are aimed at being more discrete, potentially at the expense of traction. Drive wheels with low traction can result in slipping, especially during rainy weather or when your lawn is wet.

It depends to a large extent on what the main purpose of the robotic mower in question is. Some mowers are designed for small flat areas, whereas others are designed for more heavy-duty work or uneven terrain. Check out the list of recommendations we have at the end of this article to compare the maximum mowing gradients of specific models.

Weight Distribution

Different models and brands have different design philosophies when it comes to weight distribution too. The position of the motor and other components can have a huge effect on the overall weight distribution of your robotic mower.

For operation on hills and inclines, it is generally best to look for models that have their weight as evenly distributed as possible, or with most of their weight on the drive wheels. It is also important to stay away from top-heavy designs if you need your robotic lawn mower to mow on hills, but fortunately most modern robotic lawn mowers are fairly compact and streamlined.

Power of the Drive Motor

The power output of the drive motor naturally also plays a huge role in determining incline operation capacity when it comes to robotic lawn mowers.

Motors need to be sufficiently powerful to ensure that your robotic lawn mower can climb and maneuver on hills when mowing. Weaker motors may be fine for even areas but the power output is an important thing to bear in mind when assessing whether your robotic lawn mower will be able to “cut it” (no pun intended).

Battery Life

Operating on inclines also requires more power than is the case with flat lawns, and this means that your robotic lawn mower’s battery life will have to be sufficient to ensure that it does not run out of power when navigating your garden’s hills and slopes.

Most manufacturers indicate the operating time of their robotic lawn mowers based on tests conducted on even lawns. The degree of the slopes and the number of hills in your yard could therefore have a huge effect on your robotic mower’s actual operating time. With enough hills, the average mowing time could be as little as half that indicated by the manufacturer in some cases. So keep this in mind when deciding what the best model would be for your own mowing needs.

Additional Features

Depending on the features that your robotic lawn mower has, it may or may not be able to monitor the degree of the incline that it is mowing on and make adjustments to its behavior, such as movement speed, etc., accordingly.

Certain robotic lawn mower models, such as the RX and RS models by Robomow even feature a special rotary mowing design, which is aimed at auto-adjusting itself to unevenness, called a “mowing deck”.

Rain Detection

Another function that a number of robotic lawn mower manufacturers, such as Husqvarna, either include or offer as add-on features is rain detectors.

These are sensors that communicate with the mower’s onboard software and generally tell it to return to its docking station by default, although a number of models such as those in the Worx WR series, are weatherproof in addition to shipping with rain detectors.

As you can imagine, mowing wet grass on slopes could easily lead to slipping, so rain detectors can be a very handy feature to have on a robotic lawn mower!

How to Know the Maximum Slope in Your Yard

The gradient of a slope is the ratio of its height to its horizontal distance. In order to find out what the gradient of a slope is, the increase in vertical height over a horizontal distance must be divided by said distance. The final result is then usually determined as a percentage. For example, at a height difference of 5ft per 100ft, the gradient is 5 ÷ 100, i.e. 5%.

As you can imagine, measuring and determining the mathematical angles of topography is a science in itself. But if you would like to learn more about how slopes can be calculated easily, Robolever has your back! Feel free to read our other article on how to do it here.

What Slopes Can Robotic Lawn Mowers Deal With?

The maximum slopes that different robotic lawn mowers are capable of mowing on can be seen in Robolever’s exhaustive table below:

Model	Max Raising
AMBROGIO L200 Carbon Blackline	45 %
AMBROGIO L250i Elite GPS	45 %
AMBROGIO L350i Elite GPS	45 %
AMBROGIO L400	45 %
AMBROGIO L60 Deluxe	45 %
AMBROGIO L60 Elite	45 %
AMBROGIO L85 Elite	55 %
HONDA Miimo HRM310	58 %
HONDA Miimo HRM520	58 %
HUSQVARNA Automower 115H	30 %
HUSQVARNA Automower 305	40 %
HUSQVARNA Automower 310	40 %
HUSQVARNA Automower 315	40 %
HUSQVARNA Automower 315X	40 %
HUSQVARNA Automower 430X	45 %
HUSQVARNA Automower 430XH	45 %
HUSQVARNA Automower 435X AWD	70 %
HUSQVARNA Automower 450X	45 %
HUSQVARNA Automower 450XH	45 %
HUSQVARNA Automower 535 AWD	70 %
HUSQVARNA Automower 550	45 %
HUSQVARNA Automower 550H	45 %
MCCULLOCH ROB R1000	25 %
MCCULLOCH ROB S400	35 %
MCCULLOCH ROB S600	35 %
REDBACK POWER RM18	35 %
REDBACK POWER RM24	50 %
ROBOMOW RC306	36 %
ROBOMOW RS612	36 %
ROBOMOW RS622	36 %
ROBOMOW RS630	36 %
ROBOMOW RX20	15 %
WORX Landroid L 20V WR150	35 %
WORX Landroid L 20V WR153	35 %
WORX Landroid M 20V WR140	35 %
WORX Landroid M 20V WR143	35 %

Which Robotic Lawn Mowers Are Best Suited for Hills?

Now we get to the actual hard data. As explained above, there are a number of factors that can determine the actual efficacy of your robotic lawn mower on hills, but here is some concrete data to help you make a decision when it comes to choosing a robotic lawn mower for mowing on hills or slopes.

Robotic Lawn Mowers for Up to 35 % Incline

In the 35% gradient range, we have a number of options that can do the job fairly effortlessly. Our favorite picks for robotic lawn mowers that can mow on slopes of up to 35% are as follows:

WORX Landroid L 20V WR150

The WORX Landroid L WR150 is a favorite among many of our readers as it is ideal for lawns of up to 1/2 an acre in size.

Coming in at $1299 The WR150 boasts all the features you would expect from the WORX Landroid series, including the patented AIA technology, which is specific to the WORX Landroid series, and is almost identical in terms of out-of-the-box functionality.

As is the case with all models in the Landroid series, the WR150 L ships with a guide wire,. which is used to define where you want it to mow and which areas you would like it to stay away from, a 4.0 Ah battery, and scheduling functionality via the Landroid app.

As mentioned, the WR150 L also features the patented AIA technology, which makes it possible to specifically configure it to traverse very narrow pathways — something that is entirely impossible for robotic lawnmowers without similar technology — meaning that it can mow in areas that would otherwise require human intervention and can work more efficiently since it does not have to make as many wrong turns as would otherwise be the case.

Here are some of the WR150’s stock features:

• can mow on slopes with gradients of up to 35%
• 4.0 Ah battery
• up to ½ an acre maximum cutting surface
• customizable schedules and control using the Landroid app
• can pre-define mowing zones to avoid certain areas of your lawn
• comes with patented AIA technology, meaning that it can be configured to navigate pathways and complex areas
• automatically turns away from obstacles if it bumps into them
• ships with rain detector
• weatherproof
• 9” cutting width
• 1.6” – 3.9” cutting height 
• Rotating disc with 3 blades
• 2x brushless wheel blade motor
• 63 dB noise level
  

WORX also has a GPS version of this model – the Worx Landroid WR153, but the only difference between the two versions is that the WORX WR153 ships with GPS functionality out of the box.

WORX Landroid M 20V WR140

If you need a smaller version of the WORX Landroid WR150, the Landroid WR140 is a very popular choice and is perfect for small gardens. 

This model in the WORX Landroid series can mow up to a ¼ of an acre on a full charge and is specifically designed for small and confined areas. It also features the patented AIA technology, which means that it can be configured to operate in extremely tight spots.

You can also check out this video review if you would like to see the WORX Landroid WR140 in action: 

The WORX Landroid WR140 comes in at between $900 to $1000 and ships with the following features out of the box:

• can mow slopes with gradients up to 35%
• 4.0 Ah battery
• ¼ acre maximum cutting surface on full charge
• customizable schedules and control using the Landroid app
• can pre-define mowing zones to avoid certain areas of your lawn
• comes with patented AIA technology, meaning that it can be configured to navigate pathways and complex areas
• automatically turns away from obstacles if it bumps into them
• ships with rain detector
• 7” cutting width
• 2.6” – 3.5″ cutting height 
• Rotating disc with 3 blades
• 2x brushless wheel blade motor
• 63 dB noise output

There is a GPS version of this model, called the WR143. The only difference between the two is that the latter ships with GPS navigation functionality out of the box.

Robotic Lawn Mowers for Up to 45% Incline

Husqvarna is the hands-down reigning champion when it comes to mowing on slopes with gradients of up to 45%. Here are our favorite Husqvarna picks for mowing on slopes:

Husqvarna Automower 310

Our best recommendation for slopes of up to 45% is the Husqvarna Automower 310. 

Husqvarna is known for its innovation and unique features and their robotic lawn mowers are no exception when it comes to excellent design and quality.

Whereas the Worx WR140 was designed mainly with small gardens and urban yards in mind, and the Worx WR150 is more suitable for larger lawns, the Husqvarna 310 is an ideal choice for medium-sized lawns, especially when it comes to complex layouts.

The Automower 310 is priced at $1999, can cut up to a ¼ of an acre of lawn unattended on a full charge and, as mentioned, can also operate on slopes of up to 45%!

The device can operate under all weather conditions and can generally mow for about 70 minutes at a time before needing to recharge.

Here are some of the Husqvarna 310’s features:

• can mow on slopes with gradients of up to 45%
• 0.8” – 2.4” cutting height
• patented GPS navigation system
• 70 min average mow time on a full charge
• mowing area of ¼ acres
• automatic passage handling
• all-weather operation
• GPS theft tracking
• 60 db noise output

Robotic lawn mowers for up to 50% incline

REDBACK POWER RM24

OK guys, so technically the REDBACK POWER RM24 is supposed to be able to operate on slopes with gradients of up to 50%! But in our experience, low budget robotic lawn mowers can be a bit on the wonky side when it comes to actually doing what they say, especially with regard to mowing on slopes. In our personal experience, Husqvarna still delivers better results mowing on slopes, even though its maximum slope is “only” 45%.

Nevertheless, if the $900 price point is exactly within your comfort zone for a robotic lawn mower that can operate on slopes, the REDBACK POWER RM24 could be exactly what you are looking for.

Here are some of the features that the REDBACK POWER RM24 ships with:

• can operate on slopes of up to 50%
• 28V lithium-ion 4 Ah battery
• mow scheduling
• 3 cutting blades
• 1” – 2.5” height adjustment
• 1 year warranty on battery, 2 year warranty on mower
• brushless motors
• water and dust resistant
• 9.5” width
• 65 db noise level
  

Robotic Lawn Mowers for Really Steep Slopes (up to 70%)

Now for really heavy-duty mowing work on steep inclines of up to 70%, there is only one real contender in our extensive experience with robotic lawn mower testing.

HUSQVARNA Automower 435X AWD

If you are willing to invest in this $6000 beast, there is simply no comparison when it comes to overall functionality as it also comes with probably more features than any other robotic lawn mower on the market right now.

The HUSQVARNA Automower 435X AWD comes with the following impressive features:

• can mow on slopes of up to 70%
• premium “X-line” design
• 1.2” – 2.8” cutting height
• 30 min charging time
• patented GPS navigation system
• Outstanding maneuverability
• 0.9 acres approximate cutting area
• GPS theft tracking
• 62 db noise output

To read more about these and other models, as well as our favorite overall picks for 2021, feel free to also check out our other article on the Best Robotic Lawn Mowers in 2021.

Well guys, I hope that this article has helped you to understand what determines the mowing capacity of robotic lawn mowers when it comes to mowing on slopes and hills. If you have any questions, or would like us to write on any other topics relating to robotic lawn mowers or robotic vacuum cleaners, feel free to let us know!