Best Robot Mower Ambrogio, Advantage #2: The Wheels

Evaluations of robot mowers are not always complete. Often, very obvious things to consider are overlooked. One of these is the wheels.

Friction is the friend of the robot mower's wheel. If the robot does not have a sincere attempt to increase friction, the result will be spinning wheels and a stuck robot. Physics cannot be denied. 

The wheel material and its shape affects its ability to create friction with the ground. How the tire is mounted to the wheel hub is also a factor. Consider the tire's surface area and how much of the tire makes contact with the ground.

Surface area is important, but a tire design that trades-off surface area for grip has merit. Aerating spikes poke into the ground, providing more traction while also aerating grass roots.

Let's look at some examples of stuck mowers and consider how the wheels could have been designed better.

Stuck Robot Mower

Robot mowers, independent of brand, are made to ride on turf. They do not perform well when the tires come in contact with loose dirt or mud. In each of these examples, the robot encountered dirt before its mishap.




Certainly in each case the issue can be reduced by various adjustments, i.e. moving the perimeter wire, changing the driving surface for the stuck wheel, making the grass grow in bare spots, etc. However, a better wheel design with more friction between the wheel and the ground or a wheel design with spikes has the potential to avoid the issue altogether.

Wheel Traction

Ambrogio robot mowers have always had thoughtful wheel designs, even since the very early days when we started (2006). The latest Ambrogio wheels are wider and more innovative than wheels of the past. Here is a comparison of the traction between an Ambrogio 4.0 robot mower wheel vs a Husqvarna wheel.




The complete comparison between the two robots can be viewed here: Robot Mower Comparison: Ambrogio vs another brand

Another innovation of the new wheels on Ambrogio's premium robot mowers are is that the tires have a deliberate gap between the ground and the wheel hub. The gap is filled with air, but it is not pressurized, thus the air does not leak out if there is a puncture. The gap serves two purposes. One is to improve traction by enabling the wheel to shape itself to the ground. 

The second purpose is to work as a shock absorber. Uneven hard ground causes an "equal and opposite" reaction to the force coming from the ground that must come from the robot. This force is transferred to the wheel shaft and into the wheel motor gears. Reducing the strength of the shock will increase the longevity of the wheel motors since the internal gears receive less force over time.

Wheel Upgrades

Wheel upgrades are helpful for atypical lawns that have difficult terrain or other issues that may cause the robot to become stuck. Ambrogio offers "spiked wheel" upgrades (known as "hooked wheels" in Europe) for most of its mower models. This is what they look like:

They are installed on the outside of the tires with a few screws. The above wheels fit on the outside of these (standard) tires:


There are similar spiked wheels available for the premium tires that come on some models. The spiked wheel upgrades improve traction on hills while also providing a small amount of aeration of the lawn while the robot moves around. The spiked wheels are great but they should not be used on expensive/fancy brick or pavers. They will make noise when traveling on a hard surface, but worse, they will create a permanent line in the brick if they are allowed to make contact while trimming the borders. The solution is easy, though. The robot can be programmed not to trim the edges. It is a small trade-off considering you might need the spikes to enable the robot to climb a very steep hill.

Now let's compare the above to another major brand.


What I find interesting is that the knobs on the tires for the upgraded wheels do not stick out much more than the treads for the Ambrogio standard wheels. But after additional research, I discovered that the alternate brand's wheel upgrade is severely flawed. Multiple customers reported that when the robot travels across a hard surface, the robot began to vibrate so severely that a sensor tripped and shut the robot down. You can read it for yourself here: Reviews of Alternate Brand's High Traction Wheels  This type of flaw cannot be corrected without a redesign of either the wheels or the robot.

In summary, wheels are important to the performance of robot mowers, especially on difficult lawns. Ambrogio robot is the leader in robot mower wheel design. Its standard wheels are superior, and, the standard wheels can be upgraded with spikes on most models.

This is the third of eight articles my series, "Best Robot Mower, 7 Reasons to Choose Ambrogio". Subscribe via email or follow "TheRobotLadysBlog" to read them all.

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