An increase in ground clearance is a kind of tuning the chassis of a car. The goal is to improve patency. Raising the ride height is not a big problem. Only in this material it is told about seven ways to do it. On the other hand, such changes in the design entail some problems. You should definitely know about them, and take them into account when deciding to increase the clearance of your car.
Clearance is...
Clearance is a gap (from the English word clearance). In the automotive field, this term defines ground clearance, namely, the distance between the conditional surface of the road surface and the same conditional lowest point of the car. Such a definition will surely mislead many, so it is worth considering in more detail.
The conditional surface of the road surface is an imaginary plane, which is formed by four points. They are located where the wheels of the car are in contact with the real road surface. That is, if there are pits or bumps under the car at some point, then they are not taken into account. In addition, if the car, say, with one wheel is on a hill, visually the ground clearance increases. However, this is also not considered, since it is precisely the imaginary even plane that passes through all four contact spots that is taken.
The conditional lowest point of the car is the part of the car closest to the road surface, but with the exception of the wheels and elements protruding from their inner side at a distance of up to 100 mm. From this definition, it follows that some parts of the running gear and the brake system are not taken into account. What's more, when measuring ride height, mudguards, bumper pads, and any non-standard decor elements are not taken into account.
We will return to how to technically correctly measure the clearance.
Influence of clearance and other parameters on the passability of the car
It is very useful to understand that the ground clearance itself only partially affects the car's patency. This parameter, depending on the traffic situation, is always supplemented by other factors. Let's take a closer look at their interaction.
The distance between the axles (wheelbase) - the larger it is, the less passable the car is. That is, if we take two cars with identical ground clearances and different wheelbases, the one with the shorter distance between the axles will have the best cross-country ability. This is due to the fact that the conditional plane described above on a longer car will more often intersect with real bumps.
The distance between the wheels of one axle - works similarly to the wheelbase. That is, the wider the car, the less passable it is potentially. However, this parameter should not be confused with stability, or with a tendency to tip over. It is clear that a narrower car is less stable when driving on slopes. But, since we are considering the issue of ground clearance, then the patency in this factor should be identified, first of all, with the conditional plane between the wheels.
Suspension stiffness - in terms of cross-country ability, it works in close conjunction with ground clearance. So, if it is too soft, and the ground clearance is small, then under the influence of inertial forces, the car will more often touch the smallest irregularities with the bottom. The stiffer the suspension, the less this parameter affects the patency in conjunction with the clearance. By the way, excessively high ground clearance and soft springs also adversely affect the vehicle's ability to overcome specific off-road conditions.
Movement speed - affects the patency in conjunction with the clearance. So, if it is higher, aerodynamics work. The car is pressed against the road surface, and the ground clearance is automatically reduced. It is clear that the stiffness of the suspension in this case is also involved in the process. If the speed is low, then the clearance can change dramatically after passing a local obstacle. For example, when driving over a bump with sharp edges, the car squats under the influence of inertial forces and its own weight. Often this leads to the fact that the bottom clings to the real road surface, since our imaginary plane intersects with it.
Vehicle load - it would seem that this is an obvious factor that affects cross-country ability in conjunction with clearance. But it is often forgotten about. The fuel level in the tank, the number of passengers, useful (and useless) luggage - can significantly reduce ground clearance. Accordingly, in order to temporarily increase the clearance, if necessary, it is enough to simply drop off passengers or even free the trunk from heavy things.
Other factors - these include things like tire pressure, running gear health, visual tuning, and even the driving skills of a particular driver. It is useful to know about all this because an increase in ground clearance is not always a panacea, and in many life situations you can do without such refinement. We will return to this issue, but for now we will continue to develop the main topic of the material.
Ground clearance of your car
There are only two convenient ways to find out the clearance of a particular car. The first of these is to find the numbers of interest in the specifications provided by the manufacturer. Such are in manuals, instruction manuals, in summary tables and special reference books. Finding any of this is not a problem for any, even the rarest car model.
The problem is something else. Namely, the optional correspondence of the manufacturer's characteristics to reality. For example, if the car is operated with sagging springs, it is pointless to look at such numbers. The same applies to cars with non-native rims and non-standard tires. In fact, you can safely focus on the clearance from the manufacturer only when the car is completely new. Or, which often happens, it is deliberately maintained by the owner in the so-called stock state.
In other cases, the ground clearance will only have to be measured. This is not difficult to do, although there are many rules for this procedure. All of them are described further in the algorithm.
Algorithm and rules for measuring vehicle clearance:
- Remove everything superfluous - leave only those things that are supposed to be carried in the car all the time (spare tire, fire extinguisher, first aid kit, warning triangle, jack, a minimum set of running tools).
- Fill up a full tank of fuel.
- Adjust tire pressure.
- Park the machine on as level ground as possible.
- The slope of the surface also plays a role and ideally it should not be.
- There must be no passengers or driver in the car.
- Ignore mudguards, bumper pads and parts protruding from the inside of the wheels by less than 10 cm.
- Determine (visually or by “shooting in”), taking into account all of the above, the lowest point on the machine.
- Measure the distance from the found point to the surface of the site on which the car is installed.
- If there are bumps under the car, then they must be subtracted from the result.
In addition to ground clearance, it is also customary to measure the so-called exit angles. These are parameters that are geometrically dependent on the distance between the lowest points of the wheels and the respective bumpers. To measure them, you need a special tool. It is similar in appearance to the building level, but "can" show the angular dimensions with an accuracy of degrees and minutes.
Advantages and disadvantages of different clearances
The increase in clearance is a procedure aimed at improving patency. However, it should be understood that high ground clearance is not only an advantage. There are also some significant drawbacks. It is useful to familiarize yourself with them before the machine is raised artificially in one of the ways suggested below.
Advantages of low ground clearance
The advantages of low ground clearance include the following pluses:
- the best aerodynamics;
- stability;
- less roll when cornering;
- more "obedient" management;
- minimum fuel consumption;
- more stylish appearance of the car.
By the way, in pursuit of the last of these advantages, many cars, on the contrary, are underestimated. The remaining pluses go to such tuning as bonuses.
Disadvantages of low ground clearance
Most likely, the main drawback is already known to you, since you are interested in increasing the clearance. However, for the sake of completeness, let's talk about them too:
- poor permeability;
- the lower the car, the stiffer it is, as a rule;
- frequent bumper repairs;
- after tuning with excessive enthusiasm - clinging of the front wheels on the arches at full eversion;
- increased risk of dangerous engine damage.
By the way, having reduced the clearance, do not forget to find out which jack to choose later for your car.
Benefits of high ground clearance
To be fair, let's look at the other side of the coin. The benefits of increased ground clearance include the following:
- increased permeability;
- sometimes a large load capacity;
- no problems with bumpers;
- the engine does not need protection;
- full inversion of the wheels without clinging to the arches.
Although by and large, enough patency.
Disadvantages of high ground clearance
As in any other business, there are also disadvantages to increasing ground clearance:
- worse aerodynamics;
- increased fuel consumption;
- low lateral stability;
- increased tendency to tip over;
- roll when entering turns;
- a tendency to build up a car with an excessively soft suspension.
It's fair to say that most of these shortcomings should not bother you if the increase in ground clearance is done without undue fanaticism and wisely. The rest, which cannot be avoided, will have to be ignored. Actually, for whom patency is more important, he does so.
Ground clearance increase
As promised at the very beginning, 7 ways to increase the clearance will be considered here. Perhaps these are not all possible technologies. But they are the most popular, and therefore it is worth starting with them. There will be no special technical details. The task is to identify each of the common methods, as well as pay attention to its advantages and disadvantages. Well, if possible, visual images will also be.
Method number 1. Replacing sagging springs
This is the most "legal" way to increase ground clearance. If the springs are really sagging, and the clearance needs to be raised a little, then there is no better approach. From a technical point of view, it is completely devoid of shortcomings. There are, of course, financial ones - new springs will have to be bought, and for some cars they are not very cheap. Especially if we talk about original spare parts.
How do you know if the springs are sagging? There are two ways. The simplest, but not always accessible, is to compare. That is, we take our car and a similar one (you can even take a high-quality photo from the appropriate angle), and measure the distance between the top points of the wheels and the nearest points on the arches. If the difference is a whole palm placed on the tire with an edge, then nothing needs to be measured - and so everything is clear.
The second way is more complicated, but always available. It consists in measuring the height of the springs and comparing the obtained dimensions with those indicated in the specifications for a particular car. The only drawback is that it is only possible to measure the height of the existing springs correctly in the removed state. By car, they are either compressed (when it is on wheels) or stretched (in a suspended position).
It is also not superfluous to make sure that the springs are intact. In life, there were cases when one of these parts burst into two parts, while this was not noticeable by the appearance of the car.
Method number 2. Rubber replacement
In this case, we mean replacing tires with a different profile. Although, if the rubber is bald, that is, it lacks a 6 mm tread, then installing a new set is quite capable of raising the ground clearance. A little, of course, but ... As for installing tires with a different profile, in this case, with a competent approach, the ground clearance can be increased so noticeably that no other methods (more technically complex, moreover) will be needed.
This method also has some disadvantages. Including, when replacing tires with freelance ones, the speedometer and odometer will immediately begin to lie, the dynamics of the car will suffer a little, and there will also be increased fuel consumption. There may also be problems with the arches, into which the new “slippers” will fit with difficulty. Especially it is necessary to pay attention to the front wheels set to the position of full eversion.
Method number 3. Replacing discs
Installing discs with a larger diameter than standard ones is more often a visual tuning. However, along the way, this has a positive effect on increasing the clearance of the car. How much it will rise is easy to calculate. To do this, you need to take the diameter of the new disks, subtract the diameter of the regular ones from them, and divide the resulting difference in half. That is, if the wheels were 15”, and you put them on 17”, the ground clearance will increase by (17-15) / 2 = 1 inch, that is, a little more than 25 mm.
The disadvantages of this method are known. Firstly, it will not work to increase the clearance by any amount. Secondly, there is a chance of colliding with wheels touching the arches. In addition, any change in the diameter of the wheels leads to a violation of the accuracy of the speedometer with an odometer, an increase in fuel consumption and a deterioration in vehicle dynamics. The problem with low arches can be partially solved by applying this method in conjunction with replacing the springs.
Method number 4. Body kit replacement
If your car has a visual tuning in the form of a freelance body kit, and ground clearance is important to you, then this is the first thing you need to pay attention to. Often, beautiful bumpers with buffer linings hide up to 100 mm of ground clearance, or even more. In any case, removing such a body kit is much easier and technically more correct than blocking spacers or non-native springs. In addition, a low body kit on a tall car looks ridiculous and loses all meaning.
Method number 5. Installing springs from another car
A common method, which is possible due to the compatibility of car parts from different models and even brands. The first option that should be worked out is the search for springs from the same model, but in the station wagon body. They are usually not only longer, but also much tougher. The second factor will solve a number of side effects from this kind of tuning.
The second option is to select springs from other cars in general. Including, foreign cars often have higher, but suitable in other parameters, springs from domestic brands. It should also be noted that it is not always necessary to look for parts in accordance with the axes. That is, in some cases, front springs from another become like a glove on the rear axle of one car.
By the way, for many cars there are original (and not so) springs of different stiffness. Their height, as a rule, is different, and therefore there is always a chance to find something that will allow you to increase the clearance with “little blood”. Oh yes! Before you bother with the search for non-native springs, it will not be superfluous to make sure that the parts available on your car were not subject to cruel tuning by the previous owner (chopped springs).
With freelance springs, there is one important nuance. It concerns the axis that is leading in your car. If the axis is leading, then there are hinges of equal angular velocities. They are designed for a specific angle of break, and may well survive artificially high suspension. However, do not rush to rejoice. Firstly, the hinges working in a constant fracture wear out faster. Secondly, you will have to change torn anthers more often. Thirdly, when hitting good pits, broken hinges sometimes pull out “with meat”, since they have not an infinite supply of tension. Proven in practice.
Method number 6. Increasing ground clearance by installing spacers above (under) the springs
Perhaps the most popular way to increase ground clearance. Spacers can be found on almost any car. You can install them with a strong desire without the help of the guys from the service station. There are even benefits. First, they are not very expensive. Secondly, nothing needs to be changed, cut and cooked. Thirdly, the clearance can be lifted "to the skies." Fourth, if you do not like the result, you can remove it at any time. Again, everything will cost "little blood."
The disadvantages are the same as in the previous methods. We will not repeat.
Method number 7. Installing interturn spacers in springs
The last of the noteworthy ways to increase the ground clearance of your favorite car. It should immediately be said that the last one is only on this list. Among fans of such tuning, he is probably one of the first. The essence of the method is simple and clear - suitable inter-turn spacers are bought, installed, and you're done. The advantages are the same as with the previous method.
Actually, as well as disadvantages. But in this case, there are more. Firstly, it is not always possible to find suitable spacers with a swoop. Secondly, the suspension with them becomes more rigid with all the ensuing consequences. Thirdly, it will not work to lift the clearance “to heaven”, since it is technically impossible to push spacers into the springs with too large a pitch.
Tips for operating a car with a small clearance
In conclusion, I would like to say a few words to those who think that he has a car with a small clearance. Rather, give some practical advice on how to live with it. Perhaps many of these recommendations will seem obvious. But let's not forget about novice motorists, for whom any information can be new and very useful.
So, what if it’s scary to increase the clearance (laziness, expensive, it seems collective farm, and so on):
- Do not use the machine for other purposes. We bought an ordinary sedan, there is nothing to climb on it into an impassable swamp. Even with high ground clearance, reckless off-road driving can result in serious and costly problems.
- Properly overcome obstacles. Wide pits and hillocks are much more correct to pass not “on the forehead”, but obliquely. That is, allowing each wheel to overcome the unevenness separately from the brothers along the axis.
- Be careful with holes. Remember that parts protruding from the inside of the wheel are not included in the clearance size. Therefore, when driving into a hole, direct the wheels away from its edge.
- Pick the right speed. If your vehicle's undercarriage is in good condition, some small potholes are better driven at higher speeds than crawling over them. On what principle it works, read the article on how to check shock absorbers.
- Deep rut = maximum unloading of the machine. If you need to drive a track that is too deep for your clearance, it often makes sense to temporarily lighten the car. For example, when going on a picnic in the forest, the most effective way is to disembark passengers, who, according to anyone, are a lot in the cabin.
- Border = 160 mm. If the curb or curb is installed in full accordance with GOST, then its height should be just that. But it must be borne in mind that not everything in our country is done according to the standard, and also when hitting obstacles of this kind, the main role is played not by ground clearance, but by the exit angles mentioned above.
- Install protection on the engine. Sometimes this is already enough to go fishing or any other type of recreation far from civilization a couple of times a year without unpleasant consequences.
- Watch the technical condition of the parts under the car. As a rule, the bottom of the car is the exhaust pipe. It hangs on rubber hangers that like to stretch, crack, burst, tear, or even get lost. Also, the engine, gearbox and gearbox “lie” on rubber cushions if the car is rear-wheel drive. Rubber shrinks and decreases, and with it the clearance suffers. Hanging tubes, pipes, cables and wires - should also not be. It's easy to fix it somewhere higher.
In general, if you love off-road so much, and buying a car is still in your plans, think about the amount of ground clearance in advance. You can, of course, increase it later. But whatever one may say, this is a gross intervention in the design of the car. For the new model, this is a loss of warranty, and for the old one, unpredictable consequences and additional costs.
VIDEO: how to increase car clearence
Brief summary
As a result, we can say that the increase in clearance is quite real. Most of the methods described above are available for do-it-yourself work, which is important for many. However, when undertaking such events, carefully weigh the pros and cons. Especially if you intend to change something drastically, with the participation of a grinder, welding and other assistants to a driver.
