Why are cars so heavy?

Answer

You can also turn the question around: which part of your car would you like to miss so that it would be lighter? Or would you be willing to pay 10 times more for your car if it were made from a lighter carbon fiber? Why have a four-seater with a large suitcase if you usually drive around alone without luggage? Why do you drive a car to start with, a bicycle also drives (by the way, a sturdy city bike – not a driver’s model that costs fortunes – even if it weighs a few tens of kilos, then the car does not perform too badly in relative terms… )?

Here are mainly economic arguments at play, and also limits to the technical ability. For the time being, steel is one of the strongest materials that are cheaply available for manufacturing engine blocks and bodywork. They can withstand the temperatures of combustion and the forces that this entails. You would rather have made your wheel axles in steel than in Styrofoam, for obvious reasons I think. And you would rather not have your roof, by extension the entire bodywork, in a tin, you had to go over in an accident.

A car must meet all kinds of safety standards (which have an impact on the bodywork, minimum and maximum requirements for the engines) that ultimately lead to limitations in the choice of materials and construction, if one wants to make a car that is also not too expensive so that people can actually buy it.

Weight isn’t really a big factor in the energy required to propel a car – a big one, but not as big as you might think. If your car breaks down, you can even push it to the hard shoulder on your own, using your meager human strength. Even your many kilos heavy bike, if well maintained, will make good progress with a small push on a pedal. Especially bad friction of the car (streamlining, engine maintenance, and especially tire pressure) contribute to a higher energy consumption. But here too you should not inflate your tires too hard and not make them too narrow, so as to still have enough friction so that you keep grip on the road during a sudden maneuver at high speed in rainy weather. After all, a car has to be able to handle that.

Why we don’t run on compressed air yet: quite simply because that technology is not yet on the market. Developing new technologies requires a lot of time and investment, and everything has to be in order and tested before you can take it on the road, that doesn’t happen overnight. Once the technology is available, it remains to be seen how the market works – but it uses economic logic, rarely scientific. If there are people who want to buy this car, with all the advantages and the limitations that this entails (eg in terms of speed, power and load that can be carried), little stands in the way of a small success.

All in all, the technology is a very interesting development in the search for greener alternatives for the energy needs of today and tomorrow.