Owners of new cars are often faced with a dilemma: is it worth spending time and money on additional equipment if the basic equipment seems sufficient? This issue becomes especially acute when traces of sand, gravel and reagents begin to appear on the thresholds, doors and lower part of the body. Manufacturers are increasingly refusing to install mud flaps for the sake of aerodynamics and design, leaving the solution to the problem of protecting the paintwork to the discretion of the buyer.
On the one hand, the absence of protruding elements improves streamlining and reduces fuel consumption, which is confirmed by factory tests in the wind tunnel. On the other hand, actual operation on Russian roads, especially in the autumn-winter period, dictates its own strict rules. An abrasive mixture of snow, salt and small crushed stone can turn the bottom edge of a door into a sieve in one season if measures are not taken in advance.
In this article we will analyze in detail whether installing mud flaps is a necessity or a marketing ploy for services, what materials exist and how to properly approach the issue of protecting the body so as not to harm the car. You will learn about the physical principles of operation of these elements and receive an objective assessment of their effectiveness in different road conditions.
Physics of the process: how protection against flying stones works
To understand the need for installation, you need to consider the mechanics of wheel movement. When the tires rotate, they emit a stream of air containing particles of dirt, water and solids from underneath them. Without an obstacle, this fan flies strictly tangentially to the radius of the wheel, often landing directly on the body elements located behind the arch. Mudguard (or apron) acts as a physical barrier that interrupts this trajectory.
The main task of the element is to change the flow vector. Instead of hitting a door or threshold, a stream of air containing dirt is thrown down toward the ground. The efficiency of this process directly depends on the geometry of the product. A size that is too small will not cover the affected area, but a size that is too large may create unnecessary resistance or even be damaged by uneven roads.
⚠️ Attention: Installing mud flaps does not provide a 100% guarantee of body cleanliness, but reduces the intensity of abrasive effects by 60-70%, which is critical for preserving the factory varnish.
It is also important to take into account the aerodynamic turbulence generated behind the wheel arch. A properly designed apron not only “catches” stones, but also stabilizes the air flow, preventing the formation of vacuum zones that can suck dirt into hard-to-reach areas of the suspension. This is especially true for low-slung vehicles.
Arguments “FOR”: why body protection is necessary
The main argument in favor of installation is to preserve the presentation of the car and protect the metal from corrosion. Even microscopic chips that appear from impacts with gravel eventually become pockets of rust. In an aggressive urban environment, where roads are sprinkled with chemicals, the oxidation process occurs rapidly.
The second significant argument is savings on car washes. A car without mudguards gets dirty much faster. A dirty streak on the bottom of doors and sills appears after every rain or drive through a puddle. The presence of protection allows the car to stay clean longer, which reduces the frequency of visits to the self-service car wash.
The third factor is the safety of other road users. Stones thrown from under the wheels can damage the glass of the car in front or stain its headlights, reducing visibility. In some countries, the presence of mud flaps on commercial vehicles is a mandatory legal requirement, and although this is still a recommendation for passenger cars, driving culture dictates its own standards.
- 🛡️ Preservation of paintwork from abrasive wear and chips in the lower part of the body.
- 💰 Reducing the frequency of expensive body washes and polishes during the winter period.
- 🚗 Preventing stones from being thrown into the windshields of cars following behind.
Don't forget about resale value. When selling a car, the buyer always pays attention to the condition of the sills and arches. The presence of sandblast marks can be a strong argument for reducing the price, while a protected body looks more presentable.
Arguments “AGAINST”: aerodynamics and design
Opponents of the installation of mud flaps often cite the deterioration of aerodynamic characteristics. Indeed, any protruding elements increase the drag coefficient (Cx). For racing cars or cars, where every gram of fuel counts, this is critical. However, for civilian cars in the urban cycle, the difference in fuel consumption will be microscopic and almost invisible to the driver.
The second argument is aesthetics. Many modern cars are designed with clean lines in mind, and plastic trim can be distracting, especially if chosen incorrectly. Cheap universal mud flaps often look foreign and can ruin the visual integrity of the car's profile.
The third nuance is the risk of damage when parking carelessly near high curbs. Plastic is a brittle material at low temperatures. An awkward movement can lead to damage to the fastener or the apron itself. However, modern materials, such as polyurethane, are highly elastic and return to shape after deformation.
Effect on fuel consumption
In reality, installing four standard mud flaps increases fuel consumption by less than 0.1-0.2 liters per 100 km when driving on the highway at high speeds. In urban mode, where speeds rarely exceed 60 km/h, the effect on aerodynamics and, as a consequence, on engine efficiency tends to zero.
There is also an opinion that mud flaps can contribute to the accumulation of moisture and dirt in hidden cavities if they are installed incorrectly or have poor sealing in the contact areas. This can accelerate the corrosion of hidden elements, but this risk is relevant only when using low-quality products or violating installation technology.
Comparison of materials: rubber, plastic or polyurethane
The choice of material is not just a matter of price, it is a matter of durability and functionality. There are three main types of mud flaps on the market, each of which has its own physical and chemical properties and area of application.
Rubber models are classics, proven over decades. They are soft, not afraid of frost, and can be easily cut to size. However, they have a significant disadvantage: over time, the rubber becomes tanned and loses elasticity, and in severe frosts it can crack. In addition, they often look rustic.
Plastic (usually ABS plastic) options are rigid and hold their shape well. They perfectly follow the contours of the arches if made for a specific model. But in the cold, plastic becomes brittle, and a hit with a stone or contact with a snowdrift can split it. But they are durable in terms of color and do not fade.
Polyurethane mudguards are considered the golden mean. This material combines the strength of plastic and the elasticity of rubber. It does not crack in the cold, withstands impacts and is able to restore its shape after deformation. This is the optimal choice for harsh climatic conditions.
| Characteristics | Rubber | Plastic (ABS) | Polyurethane |
|---|---|---|---|
| Elasticity | High | Low (hard) | Very high |
| Frost resistance | Medium (tanks) | Low (cracks) | High |
| Service life | 2-3 seasons | 3-5 years | 5-7 years or more |
| Appearance | Simple | Aesthetic, model | Modern, neat |
When choosing, you should also pay attention to the presence of a metal reinforcement inside the mudguard. Some manufacturers incorporate a thin steel plate into the bottom, which prevents the edges from curling and extends the life of the product. This is especially true for the front mudguards, which absorb the main flow of stones.
Features of installation and care of aprons
Installing mud flaps is a procedure that you can do yourself with a minimum set of tools. However, there are important nuances here, ignoring which can lead to damage to the body. The main problem is the attachment points. If the car does not have standard holes, you will have to drill the arch or use double-sided tape.
Drilling requires care and mandatory treatment of the edges of the hole with anti-corrosion agent to prevent rust. Using only adhesive backings (adhesive tape) is less reliable, especially in winter, when the weight of snow and ice acts on the mudguard. The combined method (screws + tape) is considered the most reliable.
☑️ Checklist before installation
Caring for installed elements also has its own characteristics. When washing a car with high pressure, you need to be careful: the jet at a 90-degree angle can bend the soft splash guard or tear it off if the fastening is loose. In winter, you should not pull the frozen mudguard with your hands - it is better to carefully break off the ice or wait for a thaw.
⚠️ Attention: When installing on cars with body kits or aerodynamic packages, make sure that the mud flaps do not rub against the pads when driving over uneven surfaces, otherwise the paint will be stripped down to metal.
Check the condition of fasteners regularly. Vibration and temperature changes can weaken the screws. If you notice that the mudguard has begun to “walk” or dangle, tighten it immediately so that it does not start hitting the arch, erasing the protective layer.
Use special clips for mudguards instead of standard screws, if they are included in the kit. They have a cap that does not rust and presses the plastic tightly without deforming it.
Legal aspect and traffic rules requirements
Many drivers are concerned about the legality of installing non-standard elements. According to the current traffic rules and technical regulations, the installation of mud flaps is not a change in the design of the vehicle, requiring registration with the traffic police, if they do not protrude beyond the dimensions of the car.
However, there is a nuance with the elements protruding beyond the body. According to GOST, car parts should not protrude more than 400 mm beyond the plane of the inner surface of the sidewall (for passenger cars). Standard mud flaps usually meet these standards, but installing extremely wide "aprons" on lowered cars may raise questions among inspectors.
It is also important that mud flaps do not obscure lights (if they are located low) or license plates. Otherwise, the presence of protection from dirt is a voluntary matter and encouraged by common sense, and not by regulations.
The installation of certified mud flaps that do not change the dimensions of the car is completely legal and does not require changes to the vehicle documents.
It is worth remembering that in the event of an accident or a controversial situation on the road, the absence of mud flaps cannot be a reason for a fine, but their presence can play a role in proving your integrity as a driver who cares about the safety of others.
Final summary: to put it or not?
To summarize, we can say with confidence: if you operate a car in urban conditions with the active use of reagents or often drive on dirt roads, mud flaps are a necessary investment in the safety of the body. The costs of purchasing and installing them are not comparable to the cost of repainting thresholds or fighting corrosion after a few years.
If your car is a Weekend car, which only goes out on clean roads in dry weather, or you plan to sell it in a year or two, then you can limit yourself to regular washing and anti-corrosion treatment of the underbody. However, for most drivers in our latitudes installation of high-quality polyurethane mudguards is the most rational solution.
The main thing is to choose the right material and high-quality installation. Do not skimp on fasteners and do not install “oak” rubber products that will turn into rags in six months. A well-chosen accessory will become an inconspicuous but reliable protector of your car.
Do I need to remove mudguards for the summer?
It makes no practical sense to remove mudguards for the summer. In summer, roads can also be dirty, and dust and fine gravel are as destructive to varnish as winter porridge. In addition, constant dismantling and installation increases the risk of damage to the fastening points.
Is it possible to make mud flaps yourself?
Theoretically, you can cut them from thick rubber or linoleum, but the factory geometry provides better protection. Homemade products often have a poor fit, which can cause moisture and sand to accumulate between the mudguard and arch, causing corrosion.
Do mud flaps affect off-road performance?
On serious off-road conditions, standard mud flaps can become a weak link, as they can easily be torn off by stumps or rocks. For expeditionary use, they are often removed or replaced with reinforced metal versions, if the vehicle design allows it.
How often should mudguards be replaced?
Service life depends on the material. Rubber ones are replaced every 2-3 years when they lose elasticity. Plastic and polyurethane ones last 5 years or more. Replacement is required if cracks, chips appear or the fastening is broken.