Some car specifications just make sense: “Eight airbags” means a car has eight airbags. But specs like torque, wheelbase and even more familiar ones like horsepower and weight, are often misunderstood in terms of their relevance to the process of selecting a car to buy. Too many car specs are means rather than results.
In this video I define the specs most commonly used in the marketing of cars, explain what each one means, and tell you which ones you can largely ignore. Spoiler alert: That’s a lot of them.
I also tackle the lesser-known problem with MPG ratings, explain the increasing relevance of MPGe as electric cars gain acceptance, and mention the one spec that is easiest to decipher and hardest to deal with: MSRP.
If there’s one spec I want you to come away with a newfound interest in, it’s torque. Torque is what you’ve really been looking for when you examined horsepower; It creates that fun to drive acceleration we all love, and it’s becoming more interesting at naturally torquey electric cars being to flourish.
The video above has the best explanation of important car specs, but here’s a brief summary as well:
0-60: The holy grail of performance specs. It’s the minimum amount of time a car needs to accelerate a standing stop to 60 miles an hour. A good apples-to-apples comparison between cars, but a test drive may tell you more.
12V/120V/5V: The three kinds of power typically found in a car. 12 volts DC is what comes out of what we used to call a cigarette lighter outlet, which is still inefficiently shaped to hold a cigarette lighter. 120V (also labelled as 110V and 115V) is, of course, house current and is AC. 5V DC is the power delivered by a USB port, but nobody refers to it by its voltage.
CD, or coefficient of drag: You’ll often see this when a new version of a car comes out as carmakers love to boast about how they reduced a vehicle’s drag or friction passing through the air. All you need to worry about is the car’s fuel economy, acceleration and top speed (if that matters to you), and wind noise. The Cd that helps with those can be ignored.
Displacement: Often seen as “2.0” or a similar badge on the rump of a car. This is the amount of space in the engine’s cylinders where air and fuel are mixed to combust and create power. Pay attention instead to the car’s acceleration, fuel economy and towing capacity; how much displacement a carmaker uses to deliver those is peripheral, especially with turbocharging and hybridization blurring the line between what various engine displacements can accomplish.
Headroom/legroom: I ignore these measurements. In a place like a car’s interior, full of complex shapes and deformable materials, simple stick figure measurements like legroom and headroom tell you almost nothing, in my experience reviewing over a thousand cars. Just sit in the thing. Interior cargo capacity figures are a little more useful, but just barely.
Horsepower: The standard measure of a vehicle’s engine expressed as work. 1 horsepower equals the work needed to lift 550 pounds 1 foot in 1 second. By itself, somewhat arcane. Examine the 0-60, towing load and MPG figures instead.
Kilowatt hours (kWh): This is a measure of battery capacity in an electrified car, especially important in a pure EV. It’s analogous to the size of a gas tank. The more kWh, generally the more electric range, but also the bigger chore to recharge the car.
MPG (city, highway, average): Most of us understand miles per gallon, or at least think we do. Lesser know is an inherent distortion in this spec that may bias your view of cars you compared based on it. A good explanation of the problem with the MPG spec is found at the Skepticblog. The Europeans know this; that’s why they express fuel economy as consumption-per-distance (Liters/100 km) as opposed to our distance-per-consumption rating (MPG).
MPGe: Miles Per Gallon (Gasoline) Equivalent is how the EPA makes apples-to-apples out of gas and electricity. A gallon of gas has an energy potential of 115,000 BTUs and that is equivalent to 33.7 kWh of electricity. This number helps you evaluate the efficiency of a car that can run on combustion or electricity at various times. This will become a more important spec as electrification marches on.
MSRP: This one’s easy: Don’t pay it.
Torque: This is how hard the car’s engine can twist something, and twisting is the whole idea behind moving a car: The engine twists the guts of the transmission which twists the drive shafts which twist the wheels and off you go. A really important comparison spec that too few people are familiar with.
Track: Wheelbase’s lesser-discussed sibling. The distance between the wheels, side to side across the car. Inside baseball.
Watts (audio): Audio systems can range from 200 watts to 600 watts, 1,200 watts or more. Those numbers don’t tell you how loud it gets (all of them can damage your hearing), rather they suggest how many speakers it has or, more importantly, how elegantly it can portray transient moments in music when a lot of power may be needed momentarily. Don’t sweat the number, listen to the system with a piece of music and medium (phone, USB, CD) you’re familiar with.
Weight: Lots of these and they matter. Curb weight is an empty car with a full tank of gas, perhaps the least important weight. Gross weight is that of a car and all the people and stuff it can be safely loaded with. Towing capacity is what a car can pull and bring to a stop. Those last two weights are important specs you can’t empirically judge by driving a car.
Wheelbase: The distance between the two axle lines, or centers of the wheels, on one side of a car. This can have a major effect on handling, ride quality and vehicle appearance, but judge those attributes directly. Don’t worry about the wheelbase that delivered them.
Wheel size: This is usually the diameter of the wheel, less often its width, and without the added dimensions of a tire wrapped around it. It has a major effect on a car’s handling, ride quality and appearance. It can be a good snapshot when comparing cars or trim levels, but you still have to drive the car to see how the quality of drive factors play out with a given wheel size.