People are getting heavier, but cars will get lighter

People are getting heavier, but cars will get lighter

Automakers give a figure for fuel consumption called the ADR (Australian Design Rules). It’s a test on a mixture of roads that gives an approximate everyday fuel economy reading for the car. Obviously if you live in a hilly place like Wellington, your fuel economy may be significantly worse than the ADR; and somewhere like Hamilton it might be better.

Because many manufacturers use this figure to sell their cars – it indicates how frugal they are – the automaker must use all the weapons in the arsenal of fuel economy available. These include making the car more slippery (coefficient of drag), making the engine more efficient (less mechanical loss and more efficient use of the energy created by burning petrol), lowering rolling resistance, etc.

But one of the main options has not really been used that much. In fact, manufacturers are going the wrong way: cars are getting lardy. If you read myMercedes C320 CDI review you’ll remember I poked fun at its electric headrests as being unnecessary weight from the German manufacturer.

We want all this extra gubbins in our cars for comfort, but that’s at the expense of economy. Japan’s big four (Mazda, Toyota, Honda, Nissan) are taking a leaf out of Colin Chapman’s book and striving for an ‘absence of weight’. In fact, they’re one of the top priorities to reduce the carbon footprint.

If you take Toyota, apparently the 2015 Corolla must be 30% lighter than the current model. That’ll take it back to, oooh, about the same weight as it was when it was the Levin AE86 20 years ago. Nissan wants to reduce vehicle weight by 15% by 2015,  and so on.

So, is it really back to the future? No. Older cars were lighter because they were less safe – they had no airbags, rubbish crumple zones, and less reinforcing. We’re going forward to the future where high-tech composites are used. Carbon fibre might become widespread for doors, bonnets and boots. Batteries are now half the weight they were when the Prius first came out.

And then there’s BMW’s GINA concept  – a car clothed in fabric, which is much lighter than steel.

But the problem the automakers can’t control is our weight. We’re becoming fatter. Larger people wear larger clothes, and with fatter people comes the requirement for large and sturdier seats, and wider (and therefore often heavier) cars. I don’t know the figures for the average weight of a person, but let’s say it’s now 20kg more than it was 30 years ago. Someone in a lab coat will be able to tell you how much extra fuel per 100km your car will burn having to move an extra 20kg of ballast. It might seem minuscule for one car, but multiply it by the hundreds of millions that are on the road right now.

Looks like the manufacturers will have their work cut out for them!

Automakers give a figure for fuel consumption called the ADR (Australian Design Rules). It’s a test on a mixture of roads that gives an approximate everyday fuel economy reading for the car. Obviously if you live in a hilly place like Wellington, your fuel economy may be significantly worse than the ADR; and somewhere like Hamilton it might be better.

Because many manufacturers use this figure to sell their cars – it indicates how frugal they are – the automaker must use all the weapons in the arsenal of fuel economy available. These include making the car more slippery (coefficient of drag), making the engine more efficient (less mechanical loss and more efficient use of the energy created by burning petrol), lowering rolling resistance, etc.

But one of the main options has not really been used that much. In fact, manufacturers are going the wrong way: cars are getting lardy. If you read myMercedes C320 CDI review you’ll remember I poked fun at its electric headrests as being unnecessary weight from the German manufacturer.

We want all this extra gubbins in our cars for comfort, but that’s at the expense of economy. Japan’s big four (Mazda, Toyota, Honda, Nissan) are taking a leaf out of Colin Chapman’s book and striving for an ‘absence of weight’. In fact, they’re one of the top priorities to reduce the carbon footprint.

If you take Toyota, apparently the 2015 Corolla must be 30% lighter than the current model. That’ll take it back to, oooh, about the same weight as it was when it was the Levin AE86 20 years ago. Nissan wants to reduce vehicle weight by 15% by 2015,  and so on.

So, is it really back to the future? No. Older cars were lighter because they were less safe – they had no airbags, rubbish crumple zones, and less reinforcing. We’re going forward to the future where high-tech composites are used. Carbon fibre might become widespread for doors, bonnets and boots. Batteries are now half the weight they were when the Prius first came out.

And then there’s BMW’s GINA concept  – a car clothed in fabric, which is much lighter than steel.

But the problem the automakers can’t control is our weight. We’re becoming fatter. Larger people wear larger clothes, and with fatter people comes the requirement for large and sturdier seats, and wider (and therefore often heavier) cars. I don’t know the figures for the average weight of a person, but let’s say it’s now 20kg more than it was 30 years ago. Someone in a lab coat will be able to tell you how much extra fuel per 100km your car will burn having to move an extra 20kg of ballast. It might seem minuscule for one car, but multiply it by the hundreds of millions that are on the road right now.

Looks like the manufacturers will have their work cut out for them!

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