Bumper for your car

Design, aerodynamics and protection: the bumper

From the very start, the bumper has been a standard component in automotive construction. Its original task consisted in protecting the car body against low-speed impacts. Nowadays, the bumper has other tasks, while it has lost some of its original function.

Shoving cattle, chasing dogs - the bumper's origin

The bumper is a bar, attached transversely to the driving direction on the front and the rear of the car. Until the 90ies it was actually a rigid component of pressed metal, simply screwed onto the frame of the car with four bolts. Its sole task was keeping the damage to the car to a minimum in case of minor collisions with objects. Agricultural vehicles were equipped with particularly massive bumpers, the so-called bull bars for shoving cows out of the way in case one happened to obstruct the thoroughfare on a country road, not intent upon moving an inch. For some time in the 70ies, regulation was implemented in the USA, stipulating that a car should remain undamaged in case of a collision at a speed of 5 kph. What followed can be regarded as the summit of bumper development: massive elements supported by equally massive spring elements became standard. This proved to be detrimental to design, especially for sports cars and sports coupés: with a massive block on its front, the Lamborghini lost much of its elegant appearance. The Mercedes SL's front bumper became a kind of footboard. Porsche attempted to give its 911 a high-tech appearance with bumper bellows on both sides. The entire car industry protested vehemently against the regulation, and it was eventually abolished.

Aerodynamics, technology carrier and design

Nowadays, bumpers present themselves in another light although they continue to occupy the front and rear end of the car. Yet, they are now more vulnerable and more expensive than ever. Their original purpose hardly applies now. Even the smallest impacts leave traces on today's bumpers, especially when bumpers are painted in the same colour as the car. These components are now massive plastic blocks, adapted to the car model, making their replacement rather expensive. In comparison to the earlier components of steel, plastic has several advantages: it is considerably lighter and cheaper to mould individually. The bumper of today supports the aerodynamics and the design of the car. Furthermore, today's bumper is a real technology carrier. In addition to the several types of lighting on the front, such as

• headlights
• cornering lights
• turn signals
• daylight driving light
• fog lights

the frontal bumpers also carry sensors. In new cars, proximity sensors can be found in addition to temperature and rain sensors. The concept of preventing a collision on beforehand rather than allowing it to occur as damage-free as possible, should certainly be regarded as technical progress.

Repairing bumpers

Even nowadays, bumpers are shaped to allow easy disassembly. Generally, a bumper defect only occurs as a result of impact. Nevertheless, the installed technology must be taken into account. In addition to the components mentioned earlier, the front and rear bumpers contain the triggering sensors for the airbags. Therefore the repair manual of the manufacturer should be followed exactly in order to prevent expensive damage. The purchase of new bumpers could turn out to be a rather expensive business. Therefore, repairing the original components makes sense. As long as the bumper is not completely severed or crushed, it can generally be made fit for use with the right repair kit, consisting of epoxy resin and fibre-glass mats. Painting the bumper is an unavoidable part of the procedure, making repair of the damaged bumper rather costly.