Anyone who has ever thought about buying a new car or planned a trip on broken primers, faced with the term “ground clearance”. In common usage, this parameter is called clearanceIt is often the deciding factor when choosing between an elegant sedan and a high crossover. Many drivers underestimate the importance of this figure until they hear the unpleasant grinding of the bottoms against the curb or get stuck in a snowdrift where other cars drove confidently.
In fact, clearance It determines the vehicle’s ability to overcome obstacles without the risk of damaging vital nodes. This is not just a marketing figure from the dealer’s brochure, but a real technical characteristic that affects the geometry of the passability. Understanding its working principles and measurement methods will allow you to avoid costly suspension and engine repairs in the future.
In this article, we will discuss in detail how to correctly measure the gap between the road and the body, what standards exist for different classes of cars and whether it is possible to safely increase this parameter. You will learn why the manufacturer’s 180 mm can turn into a real 155 mm, and whether it is worth chasing the maximum values.
What is clearance and how to measure it correctly
From a technical point of view, ground clearance This is the minimum distance between the supporting surface (road) and the lowest protruding point of the car. Here lies the first trap for motorists: most often this point is not the lower edge of the bumper, as many mistakenly believe, but the elements of the exhaust system, the engine crankcase or pallet protection.
For the correct measurement, you will need a flat area, roulette and, preferably, an assistant. The process requires accuracy, since a mistake of several centimeters can radically change the idea of the terrain of the machine.
- 🚗 Set the car on a perfectly flat horizontal surface.
- 📏 Find the lowest point of the central part of the bottom (usually it is a crankcase protection or silencer).
- 📐 Apply the roulette vertically to the ground and fix the distance to the protruding part.
- 🔧 Separately measure the lumen under the bumpers, as they are often the first to suffer.
It should be borne in mind that different manufacturers measurement methods may differ. Some brands indicate clearance for an empty car, others for a loaded one. That is why real-world indicators often diverge from the data in the specifications. A precise knowledge of your geometry motor-car It will help you feel more confident driving in difficult conditions.
Standards of road clearance for different classes of cars
There is an unofficial gradation of cars by landing height, which was formed based on operating conditions. For urban environments where roads are regularly cleaned and repaired, minimum values are sufficient. However, for Russian realities, especially in the regions, the requirements for the passability much higher.
Owners. sedans Class B and C must be constantly careful when parking near high curbs. At the same time, owners of full-fledged SUVs can afford to ignore many bumps, but pay for it by deteriorating stability on the track and increased fuel consumption. The golden mean is considered to be modern crossovers adapted for bad roads.
Below is a table with indicative clearance values for different body types. The data is averaged, because even within the same class, models can vary significantly.
| Class of car | Typical range (mm) | Features of operation |
|---|---|---|
| Sports cars | 100 – 120 | Only the perfect tracks. |
| Sedans (B, C class) | 140 – 160 | City and highway |
| Crossovers (C, D class) | 160 – 190 | A city, easy off-road |
| Off-roaders | 200 – 250+ | Any conditions |
Please note that the manufacturer's claims 180 mm This is often a theoretical maximum. In practice, after installing the engine protection or with a full load of the cabin, this figure can decrease by 15-20 mm. This is a critically important nuance when planning long-distance travel.
Why do sports cars have such low clearance?
A low center of gravity is necessary to improve aerodynamics and wheel grip at high speeds. It's a trade-off: you sacrifice cross-country for the sake of dynamics and stability in corners.
Factors Affecting Change in Clearance
The ground clearance is not a constant value. In the process of operating a car, many factors can change the geometry of the suspension. The first and most obvious factor is loading. The more passengers and cargo are in the car, the more the springs sag, reducing the distance to the ground.
The second important aspect is the technical condition of the suspension. Over time, the springs lose their elasticity and “set”. If your car is over 5-7 years old, the actual ground clearance can be 10-15 mm less than the factory one simply because of the natural wear and tear of the metal. Regular diagnosis of the chassis helps to control this parameter.
Also (cannot be ignored) the impact of tyres. Installation of rubber with a higher profile allows you to slightly raise the body without interference with the suspension design. However, replacing the regular wheels with larger diameter wheels with low-profile rubber, on the contrary, will reduce the gap, which can be an unpleasant surprise in winter.
- 📉 Natural shrinkage of suspension springs over time.
- ⚖️ Overloading the car with passengers and luggage.
- ❄️ Sticking snow and dirt on the bottom and in the arches.
- 🛞 Change the size of tires and wheels.
Especially relevant is the problem of snow dumps in winter. A layer of snow stuck to the bottom can reduce effective clearance by a few centimeters. Drivers. It is recommended to periodically inspect and clean the arches and the space under the bumpers in winter.
Before buying pads, be sure to check the condition of the springs. If they have already subsided, replacing the springs will be more efficient and safer than installing additional elements.
Methods of increasing ground clearance
If the standard height is not enough for your needs, there are several ways to increase the clearance artificially. The most common and budget option is installation slat under springs or shock absorbers. They are rubber, plastic or aluminum and are installed between the turns of the spring or in the place of fastening of the shock absorber.
A more radical method is to replace regular springs with reinforced analogues with more turns or from more rigid steel. This method is preferable from the point of view of saving the suspension life, but requires a competent selection of components so as not to upset the balance of shock absorbers. It is also practiced to install wheels of larger diameter, if the design of the arches allows.
⚠️ Warning: Excessive increase in clearance (more than 30 mm from normal) shifts the center of gravity of the car upwards. This leads to deterioration of handling, increased rolls in corners and accelerated wear of joints of equal angular speeds (SRUS) and Silentblocks.
Some modern cars are equipped with air suspension systems that allow you to change the height of the body at the click of a tumbler. This is an ideal but expensive solution that is rarely found in the budget segment. For most owners, the optimal compromise remains between a moderate elevator and maintaining the factory handling characteristics.
☑️ Check before installing the pads
Impact of clearance on manageability and safety
High clearance is not only an opportunity to drive on a high curb, but also certain risks on the track. Cars with a larger gap have a higher centre. In emergency situations, such as a sharp detour of an obstacle ("elk test"), such machines are prone to heavy rolls and even rollovers.
Aerodynamics also suffers with increasing distance between the road and the bottom. Under the bottom, air swirls are formed, which create lift at high speeds. This leads to a deterioration in the grip of the wheels with the road and an increase in fuel consumption. Therefore, racing cars, on the contrary, are pressed to the ground as low as possible.
It is important to understand the difference between geometric and physical patency. Even if the clearance allows the log to move, it does not mean that the suspension will withstand the impact. Hard bumps about unevenness can damage not only the elements of the suspension, but also the mounting of the engine or transmission.
- 🌪️ Deterioration of exchange rate stability in side wind.
- 🔄 Increased radius of roll during maneuvers.
- ⛽ Increase in aerodynamic drag and fuel consumption.
- 🛡️ The risk of damage to unprotected nodes during the "breakdown" suspension.
Therefore, choosing a car with high clearance, you should be aware that you are sacrificing some sharp, "karting" handling for the sake of cross-country. For a family car, this is often a justified compromise, but for a lover of active driving on the serpentine, high clearance can be a source of discomfort.
Optimal clearance is a balance: the car should not be scratching the bottom on ordinary roads, but should not fall in corners like a ship.
Care behind the bottom of the car
Regardless of the size of the ground clearance, the lower part of the body requires protection. Road reagents, dirt, stones and moisture are the main enemies of metal elements. Regular washing of the bottom, especially in winter, helps to wash away the aggressive salt that provokes corrosion. Ignoring this rule can lead to end-to-end corrosion over a period of years.
An effective method of protection is the application of anti-gravel coating or liquid-plastic on the lower parts of the bumpers and rapids. These materials create an elastic layer that takes on the impacts of small stones and prevents chipping. To protect the crankcase and gearbox, it is recommended to install metal or composite protection.
⚠️ Warning: When installing an abnormal engine protection, make sure it has holes for ventilation and oil drainage. Deaf protection can lead to overheating of the engine in summer and accumulation of moisture inside the casing.
Visual inspection from the bottom at each climb on the overpass or lift in the service is a useful habit. Pay attention to the condition of the anthers of the SRUS, the integrity of the muffler corrugated and the presence of fresh undertekts of technical fluids. Finding a problem early will save your budget.
Do you need plastic protection under the engine?
Plastic shields that the plant puts in mainly perform an aerodynamic function and protect against dirt. For serious protection from rocks and ice, it is better to install an additional metal sheet, but watch the weight.
FAQ: Frequently Asked Questions
Is 160mm clear enough for winter?
For most city roads and even for suburban destinations, 160 mm is quite enough if you are driving on a rolled-up track. However, in deep snow or in uncleaned parking lots with snowdrifts, this may not be enough, and there is a risk of "sitting on the belly."
How safe can you increase the clearance?
Safe is considered an increase of 15-20 mm from the factory value. Exceeding this threshold may require replacing shock absorbers with longer ones and will adversely affect the suspension life and traffic safety.
Does the pressure in the tires affect the ground clearance?
Yes, it does, but it's a little bit. With severe under-pumping of tires, the profile height decreases, and the car drops slightly. However, this is not a method of adjusting clearance, but a factor that should be considered in accurate measurements.
What is the angle of entry and how is it related to clearance?
The angle of entry is the maximum angle at which a car can drive into an obstacle without touching it with the front bumper. It directly depends on the front overhang of the body and the value of the ground clearance in the front part.
Does the clearance change when the engine is heated?
Technically, the thermal expansion of the metal and the change in the viscosity of the oil in the shock absorbers can give a microscopic error, but for the driver these changes are imperceptible and do not affect the passability.