Frequently Asked Questions

Making sure that you use the proper air pressure is extremely important as it has an important impact on the tyres' durability and on driving safety. If the air pressure is too low, the rolling resistance is increased and this can lead to a higher fuel consumption. Official reports show that only one in four cars are using the correct air pressure. The tyre pressure recommended by the car manufacturer can be found in the handbook of that vehicle, on the fuel filler flap or on one of the door posts, usually the driver's. The air pressure should be checked at least every four weeks. The air pressure test should be performed on "cold" tyres (before the vehicle is driven and heat is generated).

The aspherical mirror features a split mirror surface that has a convex curvature that increases the driver's rear view angle. This allows the driver to see more of the back of the car and following traffic. So the driver can avoid the blind spot that occurs when looking in a conventional flat mirror.

The automatic climate control offers the driver an extra comfort while driving. Using the automatic programming function, a comfortable temperature can easily be reached and maintained. The temperature can also be set manually.

Bi-turbo refers to an engine that has two turbochargers (bi = two). These turbochargers are mounted on either side of the engine. It is also known as "twin-turbo".

A sensor records every operation of the brake pedal thus observing the force with which the brake pedal is pushed. This sensor alerts the driver through an audio or visual signal if he exceeds the posted speed limit: “Warning: emergency brake!” A solenoid valve that ventilates the booster and increases the brake pressure is activated. As soon as the driver releases the brake pedal, the brake assistance is automatically disabled.

Brake boosters or brake servos are auxiliary braking devices designed to help improve braking performance. The power that the driver uses when braking is assisted by these brake boosters. This booster is significantly important for brake pads as they require a higher hydraulic pressure. The boosters are controlled mechanically by using the brake pedal hydraulics. In case of pressure loss, this system works as a hydraulic brake system although an increased foot braking pressure has to be appliedby the driver. The human power alone is usually not enough in order to reach the required braking force that cars, commercial vehicles or buses need. Servo-pneumatic power is used as the additional force. Brake fluid systems can be pneumatic or hydraulic. When it comes to cars, a servo pump can be added by using the servo system. Nowadays, almost all cars are equipped with adequate boosters.

Also known as proportioning valve or disc brake valve, it refers to the distribution of brake force that ensures the equal increase of pressure in both front and rear axles. When reaching the switching point, this brake regulator ensures that only a low pressure is enforced upon the rear axle. This happens when pressure increases.

The brake pads are responsible for partially locking or stopping the wheels when the brake pedal is pressed. This occurs on vehicles that do not have anti-lock braking systems (ABS). If the pressure that occurs is too high, the tyres can be damaged by causing flat spots.

This refers to the distance a vehicle will travel from the moment the brakes are ressed until the wheels completely stop. The braking distance is influenced by many factors including the driver's reaction time, the road conditions, the vehicle’s speed and the tyres that are being used (manufacturing pattern type, tread depth, air pressure and evenness of the wear).

Having a high load carrying capacity, C-type tyres are specially made for commercial vehicles, vans and light trucks. These tyres can be used on small trucks, transport trucks, platform trucks, trailers, vans or any other vehicles that have to carry heavy loads at any speed. Multilayered carbonor steel wire reinforced tyres are the best solution for heavier vehicles (HGVs).

The purpose of the controlled deformation zone is to uniformly divide the energy generated by an impact. The car's bodywork must be stable and should have a fixed structure (thus providing passive safety).
The front and the rear sides of the car must have the so-called "crumple zones". When the front and the rear sides of the car are deformed, a part of the kinetic energy is stored by the bodywork. Thus, the passengers are protected during an impact. During the so-called "crash-test", these crumple zones are also tested.

In the event of an accident or major impact, the crash sensor is activated along with the hazard lights. The crash sensor unlocks all doors allowing the emergency crews to get into the car.

This refers to tyres that are considered “devalued” or have a Defective Appearance by the tyre manufacturer because of some visual flaw(s). These tyres are considered technically soundin construction and opperation and totally suitable for driving. They carry the mark “DA” stamped on the sidewall. There should not be any issues during their usage.

This abbreviation stands for “Digital Diesel Electronics” system. DDE controls the process of fuel injection, the fuel efficiency and the boost pressure. Extremely precise, DDE makes sure that the diesel engine is running properly. A greater fuel efficiency and lower emissions are among DDE’s positive beneficial effects.

A general operating instruction (ABE) is required to register a vehicle and for it to be allowed onto public roads. The official document for ABE is the KFZ label, the registration certificate. In this document among other things are - country details, the number of seats, codes and trailer information, also changes in TUV licensed cars (width of tyres, bodywork components etc.). Changes that were made to the vehicle and were not reported in the label may invalidate the KFZ EBA's and are punishable by law.

The legislation requires that all cars must have two independent brake systems: the service brake (or the foot brake) that acts on each wheel and the emergency brake assist (or the handbrake) that acts either on the rear wheels or on the front wheels. The handbrake is triggered by pulling a lever or by using an extra pedal. The handbrake device is made of a cable system that triggers the mechanism by pulling the lever in the proper position. If the service brake fails, the handbrake can be used as an alternative. When driving at high speed, the driver must be careful when using the handbrake as it may cause the vehicle to swerve.

The behavior of Nox emission describes the feature of an engine to determine the quality of “gases” while functioning.

When you accelerate harshly or especially when you are on a smooth road, the TCS prevents the wheel from slipping. The wheels will automatically be decelerated and the engine's power will be reduced. The TCS improves the traction when the car is being steered too. A slalom test showed that a car without TCS slips while the one with TCS remains still on the road.

Also known as "balloon tyres", low pressure tyres have a large volume of air and high elasticity; its weak features become obvious when driving on twisty roads.

Tyre sipes are thin slits on a moulded into a tyre's tread. On winter tyres, they improve traction when speeding up and increase safety when braking.

Abbreviation for “General operating instructions”.

ABV - automatic brake blocking. The anti-lock prevents the wheels from locking during braking by controlling the brake pressure so that the vehicle remains steerable. Depending on the vehicle, the type of ABV and the road surface, a reduction in the braking distance can be expected. See also ABS and ESP.

Active safety technical measures on the vehicle refer to the (positive) influence the "active" driving behavior and how to avoid accidents. Amongst other features, active safety is assured by the chassis . It is supported by the excellent braking system with ABS as standard. Also, the power steering with its precisely defined steering force feedback helps to better handle critical situations.

Aerodynamics refers to the power shifts that affects suspended bodies. The concept has been used in the automotive industry for some time because air resistance was noticed as an important factor in a car's operating costs. At the beginning of the automotive industry, cars were built practically. Nowadays, they are built aerodynamically. The more aerodynamic the car's body is, the less power is required in order to reach a certain speed and the smaller the engine required. The wind tunnel and the water tunnel are based on the experiences that have come from aircraft construction and is applied still today in the automotive industry. Usually, the result is pretty level because the air drag only allows for the existence of certain forms.

The air conditioning system is made of a cooling system, a heating system, a humidity control system and a ventilation unit. The air conditioning system assists the vehicle’s heating and ventilation systems.
Unlike the automatic climate control (the Climatronic system), the air conditioning system is manually controlled by the driver. Besides adjusting the temperature, the air conditioning system also controls the air’s circulation and humidity; it also offers control on how clean the air is inside a car. Air cooling is based on the same functioning principle as a heat pump. The heated air is put through a fan and sent into an evaporator where the heat is removed. The defrost function can be activated during the cold season.

Driver, passenger and lateral airbags protect against head and chest injuries that can occur in a car accident. The driver's airbag is integrated into the steering wheel. The passenger's airbag is integrated into the dashboard's plastic panel whose stitches break when triggered. During an accident, a sensor (located at the front of the dashboard) triggers a pyrotechnic gas generator that fills up the airbag with nitrogen in less than 50 milliseconds. The full size version of the driver's airbag can hold 80 liters of gas and the passenger's airbag can hold up to 150 liters of gas.

When it comes to car tyres, besides using summer or winter tyres, producers offer a third option:all season tyres. These tyres can be used all year round, regardless of the season.
All season tyres carry the “M+S” marking just like winter tyres and are also known as “all-weather” tyres. Their symbol is molded into the tyre’s sidewall and symbolizes various weather conditions; it can either be a snowflake, a leaf or a sun and rain drops symbol. These type of tyres should only be regarded as a compromise as their performance in extreme weather conditions (high temperature or extreme cold) is not ideal.

ABS anti-lock braking system prevents wheel locking up and stopping suddenly. Advantage: the car remains fully steerable! A central electronic control device with speed sensors at each wheel reduces the number of revolutions of a wheel - or all wheels, recognizes the danger of locking and immediately reduces the brake hydraulic pressure to that wheel. The type of ABS hydraulic unit contains 3 to 4 channels at the wheel brake cylinders. On wet or dry roads, the braking distance is usually the same or less as the same vehicle without? ABS. Braking distance may be longer on snow or gravel. Attention: for emergencies push the brake pedal "hard".

The functioning of the electronically based anti-slip systems (ASS) is to prevent the spinning of the drive wheels. Using sensors, the driving force is distributed so that no wheel gets more power than it actually needs to drive it. In contrast to the limited slip differential that operates mechanically, the spinning of the wheels does not ultimately prevent it with anti-slip systems. Engine performance is also influenced, so that the wheels get fed only as much power as is actually necessary. Some systems may affect the brakes at speeds of up to 40 km/h and thus prevent the wheels from spinning.

It occurs when the water that accumulates between the wheels on the vehicle and the road surface cannot be directed to the tyre's surface and is too much for their tread gooves. The tyre will "hover" on that water which can lead to malfunctioning steering and to the loss of kinetic energy. Aquaplaning is distinguished by light steering, simultaneous wheel rotation and the sound of water underneath the vehicle. During aquaplaning, the driver must not brake suddenly; he should slowly release the accelarator pedal and continue controlling the steering wheel in the direction of the road. When the car is back on the track, make sure the wheels do not lock or be positioned in the wrong direction of travel. When the car is set on cruise control, the driver must be very careful on twisty roads. Indeed on wet roads it is better not to engage cruise control at all. Drive safely in the rain!

Automatic Stability Control plus Traction (ASC+T) prevents wheel spin and provides driving stability. Up to a speed of 25 mph, the ASC+T system adjusts the brakes, automatically blocking the wheels from spinning. At speeds of more than 25 mph, slipping is inevitable.

The aspect ratio refers to the height of the sidewall divided by the tyre's width. Let’s take for example the following tyre size: 175/70 R13 S. In this case, 70 indicates that the tyre’s height is equal to 70% of its width. This is also known as a “70 series tyre”. Nowadays, on the tyre market, series range between 80 and 25. Tyres that have an aspect ratio of 55 or lower are regarded as “low profile tyres”.

When you speed up or are driving on slippery roads, it handles the side-slip(ASR) of the driving wheels when spinning. If spinning, the wheel is automatically braked and the engine power slowed down. Also ASR improves the grip in bends.

This refers to tyres that do not have either a uni-directional or directional pattern. Therefore, these tyres are cross rotated and can be fitted both on the left or the right side of the vehicle. After fitting asymmetric tyres, they may look as if they have been mounted backwards. It is compulsory to follow the instructions when mounting this type of tyre. They have either an "inside-outside" pattern identicator or a "this side out" marking.

Bar is a metric air pressure measurement unit. The Imperial air pressure measurement is pounds per square inch (psi).

When it comes to the boxer engine, the pistons are operating in an 180° angle on the crankshaft's sides. This is the reason why this engine design is also known as "the V engine". Because of the design, the engines are flat and require less engine bay height. The most famous boxer engine is the one that was produced for the VW Beetle. The most remarkable evolution of a boxer engine is found in Porsche 911 cars.

The brake fluid is made of "Polyalkylenglycol" (highly poisonous and corrosive) and other additives. Their purpose is to transmit pressure from the brake pedal and the brake cylinder to the hydraulic brake system. The brake fluid’s boiling point is 290 C° in order to avoid creating vaporisation when the brakes are firmly pressed. The hygroscopic nature of the brake fluid requires it to be changed at the prescribed service intervals. A small quantity of water can significantly lower the boiling point and can cause air bubbles. This has a negative effect on the braking pressure because the gas (air) can be compressed unlike the brake fluid.

By changing the weight dynamic in relation to the position of the brakes, the front wheels must acquire a higher braking power in order to avoid locking the rear wheels when the brakes are used. When it comes to front-wheel drive vehicles, the front axle of the vehicle is always heavier than the rear axle. This means that the center of gravity is located to the front of the vehicle. In this case, the center of gravity can be balanced by using rear wheel cylinders. This is how the proper distribution of the brake force is achieved. It is important for driving safety to make sure that the brake force is properly distributed. In order to achieve that, the following things are required: an anti-lock braking system that reduces the braking pressure and a valve that blocks that pressure and keeps it on the rear wheels. The valve's blocking becomes useful when a certain hydraulic pressure is reached. The brake pressure regulator equally divides the pressure between the front and rear wheel brakes. When the switching point is reached and the pressure on the front axle increases, the brake pressure regulator helps to balance the overall pressure. Individual brake pressure regulators are similar to the typical brake pressure regulators with the distinction that the first type controls the switching point according to the load status thus preventing the rear axle from locking. This way, the vehicle’s handling is controlled by connecting the axles to the rear of that vehicle.

The carbon monoxide is an odorless gas produced by an incomplete combustion (exhaust gas). If carbon monoxide is accidentally inhaled, it can get into the bloodstream where it affects the oxygen-carrying capacity of the blood.
In higher concentrations, the carbon monoxide can cause headaches and dizziness; in extreme cases, it can lead to fainting or death by asphyxiation.

Also known as the drive shaft, this mechanical device is used on rear wheel drive vehicles that have the engine and the gearbox fitted in the front of that vehicle. The cardan shaft is used to make a differential connection between the engine, the gearbox and the wheels. In order to do this, a plaque that makes a connection with the rear axle is attached outside the gearbox. This cross-shaped plaque is known as the cardan shaft. This is made of a metal cylinder that can be adjusted in terms of thickness and length so that it meets the vehicle’s requirements and its size (in most cases, the distance between the gear box and the driving axle). The cardan shaft can be made of a single piece of metal or it can be articulated.

The three way catalytic converter is the most effective, safest and most reliable form of cleaning pollutants produced by engines that run on gasoline. Polluting gas emissions like the carbon monoxide, hydrocarbons and nitrogen oxides are transformed into less effective polluting compounds like carbon dioxide, water and nitrogen. Stricter emission regulations were established in 1985 for all vehicles.
A well adjusted catalyst can improve the amount of emissions up to 90%. The required optimal composition of gas and air mixture for the converting process is adjusted by the lambda sensor and the engine control system. Although improvements have been made over time regarding the effectiveness of catalytic converters, the level of gas emissions still needs to be drastically reduced.
New technologies regarding catalyst development and the usage of new fuels have a great contribution to reducing toxic emissions.

This refers to the force that makes the car push towards its exterior radius when the wheels are turning. Depending on the vehicle’s mass and speed, this force can be stronger or weaker.

Is the rolling distance from one point on the tyre for a complete revolution. So that the circumference relates to the tyre diameter. It has influence on the transmission ratio and the speedometer. With a lower tyre series (aspect ratio), this smaller circumference tyre has the tendency to a shorter transmission Acceleration is affected favorably, but at high speeds there is the possibility of staying in the tachometer's red zone. In addition this smaller tyre will make the speedometer read higher. Acceptable tolerances are from plus 1.5% to minus 2.5%. The larger deviations will have made ??a proportionately bigger change to the speedometer's reading.

The clutch disc is a part of the clutch. It links the engine and the transmission.

Tyres specifically designed for light trucks, trucks, vans and buses. The priorities of these tyres are high mileage and fuel economy.

This refers to the mechanism that separates the air and compresses the gases; it has the same role as a reciprocating piston. The compressors' main purpose is to compress the air required in the combustion process and also to control the air flow required to increase a cylinder's capacity. This increases the engine's power and its rotation frequency (RPM or the revolutions per minute).
Turbochargers are controlled by the exhaust gases' energy flow and do not require additional energy. A compressor's advantage is given by its dissipation power that occurs early in the process; this leads to a constantly growing power. Nevertheless, the turbocharger lag only occurs at a certain speed of the engine (discharge rate).

Complete corrosion protection is regarded nowadays as standard for all relevant vehicle related areas. Bodywork areas are protected against corrosion by using hot wax. Riveted and welded parts are also protected against rust. Plastic insertions protect the vehicle against accidental impacts with stones.
Electrolyte sheets are partially or fully galvanized. A basic corrosion protection is applied through the process of phosphating and through the use of cathodic dip. Moreover, a special corrosion coating system is used along with a PVC layer to protect the cavities and the bodywork's lower part.

This form of testing is used in developing and testing car safety. It uses both elaborated software programs and physical models made of special materials to simulate various types of accidents. The purpose of these tests is to improve passenger safety, reduce the pressure on passengers during a crash and to maintain the injury risk as low as possible for traffic participants (pedestrians, cyclists, etc.)

This electronic system is also known as “autopilot”. The driver can set the speed to a particular rate and the autopilot will maintain that speed until further notice - for example braking or swiching the system off.

The dashboard contains multiple display devices, measuring instruments, control devices, lights, airbags, switches, radio etc. In the past dashboards were not as technologically endowed as they are today.

Depending on the engine’s type, the soot particles from a diesel engine usually include soot (carbon), unburned fuel, sulphur compounds, oil and metals. It is said that emissions coming from a diesel engine can have a damaging impact on health.

For maximum performance, directional tyres must be fitted to rotate in a certain direction. This type of tyre has the following advantages: reduced road noise, better wet grip and greater resistance to aquaplaning.
Asymmetric tyres and most of high performance tyres are all directional. These tyres have a directional arrow indicator on the sidewall.

DOT is short for “Department of Transportation” and refers to a code made of three or four numbers molded into a tyre’s sidewall. This code indicates the tyre’s manufacturing date and implicit how old that tyre is. For instance, “327” indicates a tyre that was manufactured in the 32nd week of 1997. Starting from 2000, the DOT code has four digits. For example, “1602” refers to a tyre that was manufactured in the 16th week of 2002.

Because electronic devices are often found in cars produced nowadays, driver information systems are a natural consequence of this evolution. The driver has access to all sorts of relevant information displayed directly on the dashboard: temperatures, important information about the proper working of the engine, average fuel consumption etc.

The 36th regulation of the Road Traffic Act states under section 4 (wheel description) that the following details must be present on all tyres that can run at speeds of more than 25 mph or 40 km/h: tyre size, speed index and manufacture date (DOT code). The E-mark label is compulsory for tyres sold within the European Union after July 1997.

The electric brakes are part of a mechanism that deals with energy recovery. When braking, the alternator acts like a generator and converts the kinetic energy into electrical energy. Both electric and hybrid vehicles use this mechanism.

The electric adjustment of the mirrors is done from inside the car, either from the driver’s side (both mirrors) or the passenger’s side. The mirrors can be adjusted according to the height and the longitudinal axis that the driver requires. The electric devices that are integrated in these mirrors adjust the viewing angle. Some electric mirrors have a memory function that allows them to go back to the default position. For instance, after the mirrors are washed. Often electric mirrors have demisting elements within the glass too.

This abbreviation refers to a tyre with "extended mobility technology" (EMT) - also known as run-flat tyres. When facing total loss of air pressure, the EMT tyres can travel up to 50 miles / 80 km at a speed of no more than 50 mph / 80 km/h. This should give the driver enough time to get to the nearest auto service or tyre dealer.

By definition the word engine is used to represent a force that transforms some form of energy into mechanical energy (to power other machines, a car and so on). The engines differ by their combustion type and the types of fuel they use.
The most common are: petrol, diesel, electric, turbine or gas engines and hybrid engines. Configurations can be in-line, V or boxer and with 2, 3, 4, 5, 6, 8, or 12 cylinders.

The actual power of the engine is not calculated but measured on the test bench. These measurements focus on the power of the engine rather then on its speed.
The maximum engine power was calculated before in PS and now in kw or bhp (also called “nominal power”). With the help of this value, the insurance rating is calculated.

In the normal combustion cylinder process, nitrogen oxides increases disproportionately with increasing firing temperatures. By recirculation of the exhaust gases only a part of it is introduced to reduce the temperature of burning. The exhaust gas recirculation system is composed of a driving pump and is electronically controlled by a fan. Exhaust gas recirculation is an effective method for reducing nitrogen oxides.

This is a special marking used by tyre producers to ensure that the tyres are fitted on the correct axle of the car. Tyres marked “front'’ should be mounted on the front axle whereas tyres marked “rear” should be fitted on the rear axle.

The fuels used for internal combustion engines are gasoline and diesel. Usually, fuel is obtained from petroleum distillation and in order to be used in vehicles, they must be as pure as possible (without any solid impurities). Fuels based on gasoline have specific densities and different octane rating or numbers: