Why Xiaomi’s Robot Vacuum Has Only One Side Brush: Engineering Secrets and Practical Implications

Owners of Xiaomi robot vacuum cleaners often notice that most models — from the budget Mi Robot Vacuum-Mop 2 Lite to the flagship Xiaomi Robot Vacuum-Mop 2 Ultra — are equipped with just one side brush. This raises questions: why did the company’s engineers abandon the symmetrical design with two brushes, like the competition? Does this worsen the quality of cleaning? In this article, we will analyze the technical, economic and ergonomic reasons for this decision, and analyze how one brush affects the effectiveness of the robot in different conditions.

Spoiler: The answer lies not in the economy (although that is a factor too), but in the unique navigation system and cleaning algorithms that Xiaomi has optimized for one-way sweeping, but everything in order, from design features to practical tests.

Design Features: Why Not Two Brushes?

At first glance, the two side brushes seem more logical: they symmetrically "rack" debris to the center shaft, increasing the grip width. But Xiaomi engineers went the other way.

• 🔧 Weight and balance optimization. An extra brush adds ~50 to 80 grams by weight of the robot, which affects the maneuverability and wear of the engines.
• 💰 Cost reduction: One brush is cheaper to manufacture, but that's not the main reason - even premium models (e.g. Xiaomi) S10+) retain this feature.
• 🧠 Cleaning algorithms. Xiaomi robots use LDS-They scan the space, they map the space to within a centimeter, and one brush makes it easier to calculate the trajectory along the walls.
• 🔄 Simplified maintenance. Fewer moving parts. = It's easier for owners to clean and replace one element.

In addition, in models with wet cleaning function (for example, Mi Robot Vacuum-Mop P), one brush reduces the risk of water splashing when rotating. Two brushes could create air turbulence, interfering with the uniform distribution of moisture.

The benefits of one brush: what does the practice say

Theoretical arguments are good, but how does one brush work in a real cleaning? Compare it to two-brush models (e.g., Roborock S7 or Ecovacs Deebot T9+):

Now, interestingly, in tests on high-pile carpets, one brush performs better than two, because two-way sweeping can confuse the pile, whereas one-way brushing is more predictable for robot algorithms, as evidenced by YouTube reviews of smart tech.

⚠️ Attention: If your Xiaomi robot vacuum cleaner starts to take corners worse, check the direction of rotation of the brush. Over time, it may wear out and start to push debris away from the shaft instead of rattling it. The solution is to replace the brush or flip it (if the model is symmetrical).

Disadvantages and how to compensate them

Of course, one brush has its downsides, and the main problems that users face are:

1. Missed garbage in corners. The robot may not be able to get to the wall because of a one-way sweep.
2. Uneven cleaning along the boards, and on the side opposite the brush, there are strips of dust.
3. Hair stranding. One brush is faster wrapped in hair and threads, because it takes all the load.

How do you minimize these problems?

Set up the “Wall Cleaning” mode in the Mi Home app

Increase the suction power for the corners (Settings → Power → Maximum)

Clean your brush regularly (once in 3-5 cleanings)

Use virtual walls to zonate complex areas

Check the direction of the brush (should rotate clockwise when viewed from above)-->

Another life hack: if the robot is constantly passing garbage in the same place, create an intensive cleaning zone in the Mi Home application (Map → Add Zone → Clean 2 times). This will cause the vacuum cleaner to pass the problem area twice, compensating for the lack of a brush.

Comparison with competitors: who is right?

Let's see how other brands are doing, like Roborock (a subsidiary of Xiaomi!) using two brushes in most models, and Ecovacs and iRobot are also favoring a symmetrical design. Why?

• 📏 The two brushes increase the effective cleaning width by 10 to 15 cm, which is critical for large spaces.
• 🔄 Universality: Two-shooted robots are better at handling different types of garbage, from large to small).
• 🏆 Marketing: Consumers see two brushes as a sign of “premium” even if the difference is minimal in practice.

Xiaomi has a trump card, however: their robots often have more powerful suction engines (up to 4,000 Pa in the Xiaomi S10+ vs. 2,500 Pa in many competitors), which partly compensates for the lack of a second brush due to suction force, and one brush breaks less often – which is important for long-term operation.

Design evolution: how the design of brushes at Xiaomi has changed

If you look back in history, you can see how the concept of brushes in Xiaomi robot vacuum cleaners has evolved:

• 2016–2018 – The first models (Mi Robot Vacuum 1) had a single brush with a hard bristles, which quickly wore out.
• 2019–2020 – Hybrid brushes with soft and hard hairs have been introduced (e.g. in Mi Robot Vacuum-Mop 2).
• 2021-2023 – In the flagship models (Xiaomi S10), the brush became asymmetrical, with elongated hairs on the edge for better capture of debris in the corners.
• 2026 – In the latest robots (e.g. Xiaomi Robot Vacuum-Mop 2 Ultra), the brush is integrated with a wear sensor that alerts you to the need for replacement.

This evolution shows that Xiaomi is not standing still, but adapting a one-way design for new tasks. For example, in models with automatic brush change (as in Xiaomi Mop 2 Ultra), the robot chooses the tool itself depending on the type of cleaning – an innovative solution that eliminates the shortcomings of one brush.

Myths and Reality: Dispelling Misconceptions

There are many myths around one brush. Let's take a look at the most popular ones.

⚠️ Attention: If you see online reviews claiming that one brush is a “marriage” or a “defect,” don’t believe me. All Xiaomi robot vacuum cleaners are quality control in the factory, and not having a second brush is a deliberate engineering decision, not a manufacturing flaw. Moreover, the documentation for the devices clearly indicates the number of brushes.

• ❌ Myth 1: “One brush is worse at cleaning". ➝ Reality: With the right settings (suction power, cleaning mode) the difference with the two brushes is no more than 10-15%.
• ❌ Myth 2: “It’s only done to save money". ➝ Reality: Yes, there are savings, but the main reason is optimization of navigation algorithms.
• ❌ Myth 3: “You can modify and install a second brush". ➝ Reality: Technically possible, but it will disrupt the robot’s balancing and could cause engine failures.

Another common misconception is that one brush wears out faster, and in fact, the life of a brush depends not on the amount but on the bristles and the frequency of cleaning, for example, Xiaomi models after 2022 use antistatic coated brushes that last longer and less electrify dust.

Practical tips: how to use one brush as efficiently as possible

To your robot vacuum cleaner Xiaomi cleans no worse than double brushed counterparts, follow these recommendations:

1. Set the direction of cleaning. In the Mi Home app, select the option "Perimeter Cleaning" (Settings → Modes → Along the walls) and this will cause the robot to pass closer to the plinths.
2. Use virtual barriers. Mark areas where the robot often lets debris through, and assign them increased suction power.
3. Clean your brush after each cleaning, especially if there are animals in the house, the hair quickly winds on the axle.
4. Check the roller condition. The central shafts with brushes also affect the quality of cleaning, and if they are worn out, even a perfect side brush will not save you.

💡

If the robot is not good at cleaning corners, try placing magnetic tape (sold with some models) in the problem area, which will create a "virtual wall" by forcing the vacuum cleaner to pass closer to the obstacle.

For owners of models with wet cleaning function (Xiaomi Mop 2 Pro, etc.), the advice is to set a minimum water level for areas along the walls. This will prevent splashing, which can occur due to centrifugal force from the rotation of the brush.

💡

One side brush is not a flaw, but a design feature that is offset by powerful suction and clever algorithms. When set up correctly, Xiaomi’s robot vacuum cleaner delivers results comparable to competitors’ twin brushes.

FAQ: Answers to Frequent Questions