Why Cars Have Gotten So Heavy (or Yo Mama’s Car Is So Fat…)

Have you ever notice how cars are like their owners? All too often now “heavy” seems to apply to both the vehicle and the nut behind the wheel.

In times when everyone seems to be discussing fuel economy, the 800-pound gorilla is vehicle weight. The fact of the matter is that our cars are heavier than they’ve ever been, and that’s killing the mpg.

Ask an automotive manufacturing executive about why cars have become so portly and you’ll get a response like the one I heard GM’s Bob Lutz give a woman who asked why GM no longer makes economical cars like her diesel Chevette: “the government mandates a thousand pounds worth of safety equipment.” Lutz is definitely in the ballpark here. While 1000 pounds might be a little larger than life, the government is indeed responsible for ordering auto companies to install more and more safety gear.

The Safety Factor
It all started with seat belts in 1964, but most Americans with any gray hair remember the turning point as being the impact-absorbing bumpers mandated for 1975 cars. The original 5-mph bumpers were much heavier – using a combination of metal, plastic and struts. Now, however, cars use Styrofoam, plastic, composites, and other lightweight materials, making modern crushable bumpers dainty on the scale – even compared to those 1950s European sports car bumperettes. So bumpers aren’t adding anything more.

Ralph Nader was a big fan of improving side impact protection. The metal beams inserted into doors aren’t necessarily light, but they’re not really that heavy, either. In this case, a little iron goes a long way.

Airbags account for quite a bit of weight in a modern car. There are at least two airbags (driver and passenger.) In some cars there are driver, passenger (both face and knee), as well as side-curtain and head airbags. With sensors, wiring and the bag units themselves, it wouldn’t be crazy to figure the median extra weight added by airbags looming at around 100 pounds. Is it weight well spent? Absolutely!

Antilock brakes and stability control aren’t mandated yet, but they will be. Both require a number of sensors, wiring, valves, etc… When compared to older drum brakes, the modern ABS-equipped discs are often lighter. All that wiring for yaw sensors in stability control weighs more than you’d think, though.

Crash testing is an interesting issue. The more solid cars do better in NHTSA/IIHS safety testing, which can be a function of weight, but usually of well-engineered design. While performing well is not government “mandated”, poor ratings can be a kiss of death from a marketing perspective. Extra weight does not guarantee good ratings, but well-placed supports can help when lighter, better performing structures are precluded by money, time and/or existing designs.

The Green Factor
Safety isn’t that heavy, but preventing pollution really is. Catalytic converters to reduce emissions and mufflers to control noise pollution are heavier than a Metallica radio marathon. Many SUVs and trucks use two pre-cats and two cats to achieve emissions standards, while also sporting two huge mufflers to come in under ever-stricter noise ordinances.

Government Grand?
At the end of the day, though, safety and emissions brings a car nowhere near 1000 pounds. So let’s look at where the rest of the fat might be.

Bigfoot
Let’s start where the rubber meets the road: wheels and tires. Back in the old days, cars used 14 and 15-inch wheels. In the 1970s and 1980s, 13-inch rubber was the norm among imports and econoboxes. Ferrari 328s had 16-inchers with wheels and tires at about 45-pounds each. Just ten years later, C5 Corvettes came stock with 35-pound run-flat tires over 25-pound 17 and 18-inch wheels. Now even Toyota Avalon sedans carry 17s and many sports cars and SUVs have 20-inchers. Larger wheels have also made way for significantly larger brake discs and calipers. Anyone who has ever tried to do brake work understands how much these components weigh. Larger wheels, tires and brakes together can easily add 250 pounds to a vehicle.

Transmitting the Weight
Engines are lighter than ever, but transmissions are heavier. In the 1960s if you had five speeds, you were probably driving a Ferrari. Now the standard is six speeds – for automatics and manuals alike, with seven (and even eight) speeds for the high-end vehicles. Since trannies are all computer-controlled, add in a box with wiring and some plastic to protect it from the elements. Use of lighter alloys and tighter packaging has kept the scales from overloading, but at some point, adding gears means adding weight.

It Makes You Feel Good, But Is It Good For You?
Where the real additional girth is now is in the interior – and it has nothing to do with safety or emissions.

• Seats: Remember when seats slid forward and back and you could just recline the seat back? Gone now, in favor of 300-way adjustable buckets with multiple air bladders. Some seats, like those on my daily driver, offer heating and cooling. BMW and Mercedes chairs massage while you drive. All those features require motors, relays and wiring. Motors aren’t light.
• HVAC Attack: I’m not sure why in my two-seat Corvette roadster I have dual-zone climate control, but I do. In some cars it is four or five zones. The more complex the HVAC system, the heavier it all is.
• Infotainment Overload: Probably the main interior offender is the entertainment/information system. Back in the old days you had one head unit (weighing less than ten pounds) and two cheap paper speakers. Now hundreds of pounds are dedicated to up to two-dozen speakers, multiple amplifiers, complex wiring and multiple components to operate a radio, disc changer, and navigation. For SUVs and minivans, a DVD system is not uncommon.
• Top Heavy: Sunroofs and convertible tops have become heavier. Panoramic multi-panel roofs can be had on everything from luxury cars to Subarus. As for drop-tops, the wild hardtop convertible contraptions that used to be reserved for anomalies like the Ford Skyliner, is now commonplace. It’s even an option on the Miata…which is supposed to be a throwback no-nonsense roadster.
• Techno-burdened: High intensity discharge headlamps need automatic leveling systems, ballasts and larger gauge wiring that traditional lamps don’t require. Laser-guided cruise controls have a sensor box mounted in the front grill and a separate computer box to manage the system. Parking assist functions range from a few pounds for an audible alert and a handful more for a rear-mounted camera to a grade-schooler’s worth of equipment to achieve a fully-automatic parallel parking job from a Lexus. Just keep in mind that most core modern automotive technologies, like drive-by-wire and direct-injection fuel management, reduce weight.
• Throw the Book At Ya: This might sound stupid, but even the owner’s manuals are overweight. The average manual from the 1960s weighed under a single pound. The combined weight of all the manuals (including several individual volumes for the car, the navigation system, the keyless entry/ignition, the laser-guided cruise control) that came with (and are still in the glovebox of) my 2006 Toyota is nearly six pounds.

Don’t get me wrong, I like butt warmers and nice sounding stereo. When I hop into a BMW 335 convertible, however, and realize that at 3960-pounds it actually weighs more than a mobile home-sized Chevy Impala with a 409ci big block, it’s startling. It is no doubt a testament to the capabilities of automotive engineers that the BMW out accelerates, out handles, is infinitely more comfortable, and gets exponentially better fuel economy than a 3705-pound 1964 Impala ragtop, a Chrysler 440-equipped 3696-pound 1973 Jensen Interceptor, a 2680-pound 1986 Dodge 600ES Turbo Convertible, or a 3471-pound ’96 Mustang GT Convertible – all vehicles that paved the way for the sport-luxury Bimmer.

The Big-Bottomed Line
Manufacturers need to cut back on this automotive version of the artery-clogger six-item breakfast from the local greasy spoon. Drop the useless huge tires and wheels – ’84 Corvettes hit 1g on the skidpad with 16”s, so anything larger is for looks. Reduce the number of multi-zones. Lighten the entertainment load…

But keep the safety and emissions controls like the vitamins we need each day.

A crash-course gizmo diet should do wonders to hitting and surpassing the 35 mpg CAFE standards. The next step is to take a page out of the auto racer’s bible: the easiest way to improve vehicle performance is to get a lighter driver.

Maybe we’d find that the weight the car and we could lose would make us…and the world healthier, more athletic and more fun. Plus neither the car or us could be the target of fat jokes.