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Jun 20, 2018

7 min. read

Car makers are busy chopping weight out of their lineup ­­- but how do they do it?

When an auto manufacturer introduces a new version of a popular model, they are bound by consumer expectations to make their new machine harder, better, faster, stronger. Thanks to a cadre of recent advancements in technology and vehicle construction, those improvements no longer have to come with a weight penalty.

The weighting game.

Chances are, then, your next new car or truck will weigh less than the one you drive today. Every kilogram counts, as studies by our affiliates have shown that reducing a vehicle’s weight by 10 percent, can improve fuel economy by as much a six or eight percent. That might not sound like a lot (on either measure) but cutting 400lbs of weight out of a two-ton car is no small task. Squeezing an extra fifty or so kilometers from a tank of fuel is equally impressive.

An image of a car being built in a factory.

Tools of the trade.

Automakers have several different arrows in their quiver of tools to achieve their goal of taking weight out of the cars they are designing. Among others, manufacturers are increasingly starting to use:

  • Aluminum construction

  • High-strength steel

  • Composite materials such as carbon-fibre

Aluminum has been used for decades in car construction, as it offers similar strength properties to normal steel, but is more unforgiving of construction errors and is expensive to repair. Costs have been driven down in recent years thanks to extensive research and development.

High-strength steel has traditionally been used in places where an item needs to bear large amounts of stress or need a good strength-to-weight ratio, such as bridges and roller coasters. This steel is different from the traditional type in, that it is manufactured not to meet a specific chemical composition, but rather to specific mechanical properties. In this case, that property is the ability to bear a certain amount of weight without weighing more than a collapsed sun. Naturally, like aluminum, high-strength steel is more expensive than traditional construction. Carbon-fibre is extremely strong, but also eye-wateringly expensive, primarily used by supercar manufacturers like McLaren.

A man is working on a car in a factory.

Biggest losers.

BMW’s new i3 electric car is a great example of effective light weighting. The compact four-seater weighs only 2,635 pounds, despite carrying around a 500-pound battery pack. This was accomplished by using a carbon-fibre (the supercar stuff) passenger compartment and aluminum sub frames to carry the battery and powertrain.

Mazda went a step further in developing its new Mazda MX-5 by employing what it called a “Gram Strategy”. By shaving off a single gram of weight here and there throughout the car, they were able to introduce a 2016 model that was not only lighter than the 2015 model, but in fact lighter than the 1999 model of the same car. In a world that demands more comfort, more technology and more safety, that feat is nothing short of remarkable.

An orange bmw i3 is on display in a showroom.

Simplify, then add lightness.

In the end, both consumers and the environment will benefit from lightweighted vehicles. That’s a diet on which we can probably all agree.

The CAA Auto Advice team provides Members with free automotive advice. If you have questions about car care, buying a new or used vehicle, auto repairs, vehicle inspection, driving costs and more, contact us by phone at: 1-866-464-6448 or email: autoadvice@caasco.ca 

Written by: Matthew Guy.

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