How the Ariel Atom Works

In chemistry, the atom is the most fundamental building block of matter. Now the automotive world has its atom -- a car so pure and simple that some people are calling it minimalist art. But the Atom, designed by Ariel Motor Company of Great Britain, is not something you enjoy from a distance. To truly experience it, you must climb into the two-seat cockpit, start the engine and punch the accelerator.

Those that have describe the Atom as one of the most amazing automobiles in recent history. Sunday Times columnist (and host of BBC's "Top Gear") Jeremy Clarkson gave the Atom five stars and said, "In terms of sheer thrills, the Atom is easily a match for the Porsche Carrera GT...This car is motoring nirvana."

But if the Atom looks like a racecar and runs like a racecar, is it really legal to drive one on U.S. highways? First, let's define "street-legal." Street-legal simply means that a car meets certain government standards for motor vehicle safety. The National Highway Traffic Safety Administration (NHTSA) establishes and enforces these standards at the federal level. States may impose additional laws or regulations that further govern what vehicles are allowed on the road.

To be street-legal, an Atom must be built as a kit car. That means everything, including the engine, is shipped to the owner in pieces. An optional road pack, which includes turn signals, a horn, rear tail lights and headlamps, is also available. The owner assembles the car in his own garage, being sure to follow all appropriate, state-mandated vehicle safety guidelines. Otherwise, the Atom is sold as an off-the-road-only vehicle -- not legal on the highway, but perfectly comfortable at the local track.

Thank You
Thanks to Jeff Beckman for his assistance with this article.

In this article, we'll look at how the Atom works and why car enthusiasts, including celebrity thrill-seeker Jay Leno, are chomping at the bit to have one in their garage.


The Ariel Atom Supercar

Image courtesy Brammo Motorsports / Ariel Atom

Strictly speaking, the Atom is a supercar, a type of sports car made in relatively low numbers and with high-performance features that rival racecars. Even with their exotic look and superlative performance, supercars are generally designed to be street-legal. But it's on the track, where speed limits and traffic laws don't apply, that supercars truly shine.

Virtually all supercars accelerate from zero to 60 mph in under four seconds and can reach top speeds of 180 mph or faster. A low weight-to-power ratio (pounds per horsepower) makes this kind of performance possible. Remember Newton's first law of motion? It describes inertia -- the tendency of an object to remain at rest or an object in motion to remain in motion unless acted upon by an unbalanced force. The more mass an object has, the more inertia it has; the more it will resist changes in its motion. That's why super-lightweight cars have such high acceleration. Their lower inertia makes them easier to move, especially when a 250-horsepower engine is generating the force causing the motion.

More Cool Cars

So how does the Atom stack up to other supercars when measured against key performance criteria? First, the Atom weighs just a little more than 1,000 pounds and comes with an engine that generates up to 300 horsepower. In contrast, a Lincoln Town Car weighs up to 4,500 pounds and has a 239-horsepower engine, resulting in a weight-to-power ratio of 19 to 1. As the table below shows, the maximum weight-to-power ratio of the Atom is far below a Town Car's -- and is among the lowest of all supercars.

Weight-to-Power Ratio
0-60 Acceleration (s)
Top Speed (mph)
McLaren F1
4.01 to 1
Bugatti Veyron
4.35 to 1
Ferrari Enzo
4.56 to 1
Porsche Carrera GT
4.97 to 1
Ariel Atom
4.10 to 1

The Atom's acceleration also stands out. Based on its phenomenal zero-to-60 performance, it has won the distinction of fastest production car in the world. The one supercar attribute you won't find on the Atom, however, is a six-figure price tag. It ranges from $35,000 to $75,000 -- a pittance when compared to the McLaren F1 or Bugatti Veyron, both of which carry $1 million price tags. Even the Porsche Carrera GT, priced at $440,000, costs almost six times as much as the Atom.

Although the Atom meets the performance criteria of the supercar category, it doesn't look like a typical sports car. That's because Formula One racers inspired its engineering. It has a nose cone, a low, wide shape and an engine mounted behind the driver, who is exposed to the elements because the vehicle lacks doors, a windshield or a roof. To help produce downward force on the vehicle, the Atom has a rear wing that also serves as an engine cover.

Image courtesy Brammo Motorsports / Ariel Atom

From a distance, the Atom even looks a little like a Cooper Formula One racing car. But unlike a true racer, the Atom isn't confined to the track. It is equally at home on the highway -- and in the car enthusiast's garage. That's because the Atom doesn't require a team of professional mechanics to keep the car tweaked and tuned. It's easy to drive, easy to maintain and economical to own. In the next section, we'll see how the Atom pulls it off.


Inside the Atom Engine

Driving is Elemental

Most production vehicles try to eliminate cockpit noise completely. In an Atom, the driver is exposed to the roar of the engine and the face-rippling force of the airflow, much like the rider of a motorcycle or a speedboat. This can be disconcerting, especially for first-time drivers, which is why a helmet is highly recommended.

Check out the Ariel Atom site to watch a video of "Top Gear" host Jeremy Clarkson test-driving an Ariel Atom.

Unlike Formula One racers with monstrous V10 engines and systems tuned to conform to strict rules, the Atom was designed to be accessible -- and drivable -- by anyone. It is fundamentally no different than the Honda Civic parked in your garage. It has:

Let's take a closer look at these systems to see what makes the Atom tick.

Image courtesy Brammo Motorsports / Ariel Atom
CAD illustration of the engine

Image courtesy Brammo Motorsports / Ariel Atom
A close-up of the North American Ariel Atom's GM
Ecotec engine.

The Engine
In Europe, the Atom comes standard with Honda's four-cylinder iVTEC engine -- the same engine used in Honda Civic and Civic Type-R models. This might seem a bit pedestrian, but the Honda iVTEC, with a displacement of 1,998 cubic centimeters and a power output of 220 horsepower (280 horsepower with tuning), is considered by many to be the best four-cylinder production engine in the world.

In North America, the Atom comes standard with a General Motors Ecotec engine made in Germany. This is the same engine GM uses in the Chevy Cobalt SS and Saturn models, and it doesn't lose anything in the translation. Available in both 2.2-liter and 2.0-liter supercharged versions, the Ecotec engine delivers between 140 and 300 horsepower, depending on the specific package. At the low end of the performance spectrum, what Brammo considers its "budget" model, the Atom could keep up with a Porsche 911 Turbo. At the high end of the spectrum, the Ecotec-outfitted Atom just might be the fastest car in the world.


Ariel Atom Chassis and Body

Image courtesy Brammo Motorsports / Ariel Atom
Building an Ariel Atom

The body of the Atom is almost nonexistent. What bodywork there is comes in the form of separate composite panels. This reduces weight, lowers the cost and allows easy access to the mechanical components of the vehicle. The Atom's designers spent a lot of time in the wind tunnel working out the aerodynamics of the vehicle. Like most racecars, the underbody of the Atom sits low to the ground, decreasing the airflow -- and the air pressure -- under the car. At the same time, the body shape generates front and rear downforces, which are vertical forces directed downward, perpendicular to the ground. As the Atom moves through the air, it is both "sucked" down and pushed down, increasing the traction of the car and giving it superior handling characteristics.

With very little bodywork, the tubular steel chassis is exposed. Indeed, it is visually one of the most stunning and unusual features of the Atom, giving the vehicle a skeletal, almost unfinished look. But don't be fooled by appearances. Expert welders handcraft each chassis using techniques and materials that ensure the highest levels of quality and safety. For example, the welders join the large-diameter steel tube with bronze and tungsten inert gas (TIG) welding. In TIG welding, the heat to melt the metal is generated by a tungsten electrode arc. The weld area is protected from atmospheric contamination by a shielding gas, usually an inert gas like argon. Because the operator has greater control over the weld, TIG welding results in stronger, higher quality welds.

Image courtesy Brammo Motorsports / Ariel Atom
A close-up of the Atom's cockpit.

The Cockpit
The Atom's composite twin-seat unit accommodates two large adults, who are cradled inside the tubular frame of the chassis. The high side rails of the Atom offer substantial protection for both driver and passenger, as do the integral front and rear rollover tubes.

The seat was also designed for safety. It has high lateral support to keep the driver optimally positioned in the cockpit to maintain control at all times. The seat can be adjusted forward and up through five positions to account for drivers of any size. Most importantly, the Atom comes with either four-point or full harness seatbelts that conform to government safety standards, as well as standards set forth by the FIA, the governing body of the racing world.


Ariel Atom Suspension and Brakes

Image courtesy Brammo Motorsports / Ariel Atom
CAD illustration of the engine, gearbox, suspension and braking systems

The Atom features a double-wishbone suspension front and rear, which consists of a short upper control arm and a longer lower control arm that hold the wheel to the frame. The control arms operate much like a hinge, allowing the wheel to move up and down. Rubber bushings at the inboard end of the control arms allow the wheel to pivot. The bushings also help to absorb road shock and reduce noise entering the vehicle. Overall, the double-wishbone suspension allows for more control over the camber angle of the wheels. Camber angle describes the degree to which the wheels tilt in and out. It can also be tuned to ensure minimal "dive" under braking and minimal "squat" under acceleration.

Koni-manufactured dampers at each wishbone provide additional adjustability. The Koni performance system includes adjustable mono-tube gas shock absorbers with nine compression and rebound settings, as well as progressive rate springs that allow for adjustment of vehicle ride height and center of gravity. Without removing the suspension, ride height can be adjusted from one to almost two inches, making it easy to prepare the Atom for any road surface or driving condition.

The braking system of the Atom offers another opportunity to fine-tune the driving experience. Brake bias, which refers to how the total braking force is distributed between the front and rear tires, is completely adjustable front and rear via a Tilton balance bar. A balance bar, or a bias bar, divides the force from the brake pedal to the Atom's two master cylinders, making sure a higher braking force is applied to the tires that need it the most. Power brakes are not used because of the extra weight they would add to the vehicle.

Next, we'll take a look at the origins of the Atom.


Atom Origins

What's in a Name?
In the late 19th century, British bicycle designers James Starley and William Hillman invented wire-spoke wheels, allowing them to build a bike that weighed much less than contemporary models. The pair decided to name their bicycle after Ariel, the mischievous airy spirit in Shakespeare's "The Tempest." One hundred years later, the name is still associated with innovative design and engineering excellence.

The mastermind of the Atom is Simon Saunders, a British auto designer who has conceived motorcycles for Van Veen and Norton and cars for General Motors, Aston Martin and Porsche. After becoming Director of Ariel Motor Company, Saunders set out to design a vehicle that afforded drivers both the thrill of a motorcycle and the safety of a car. The product of that mission is the Atom, a vehicle that many have described as part jet, part racecar and part high-performance motorcycle.

Ariel Motor Company is much better known for its motorcycles. Founded in 1898, Ariel is one of the oldest names in British motoring history. It started manufacturing motorcycles in 1902 and produced both 350cc and 500cc bikes until the late 1950s. A well-known Ariel model was the VH500 Red Hunter, a two-wheeler that could muster 26 horsepower and had a top speed of more than 80 mph.

Ariel's most famous motorcycle, however, was the Square Four, a model the company introduced in 1937. In the early days of its production, the Square Four engine had displacements ranging from 500cc to 600cc. Eventually the largest engine topped out at 997cc, put out 45 horsepower and rocketed the motorcycle to more than 100 mph. Edward Turner designed the Square Four's engine before moving on to Triumph Motorcycles, where he helped oversee the launch of the Triumph Tiger and the Speed Twin in 1937 and 1938 respectively.

The Square Four was popular, but it was heavy and expensive. After WWII, Ariel redesigned the motorcycle with a lighter aluminum engine and telescoping front forks and rear suspension. Despite the innovations, the Square Four eventually succumbed to competitive pressures, and the last model came out in 1958.

Although best known for its motorcycles, Ariel Motor Company also produced various cars, trikes, quads, delivery and military vehicles over the years. In the early 1900s, the company experimented with a then-remarkable four-cylinder car known as the Aero-Simplex. The water-cooled Aero-Simplex was inspired by four-cylinder designs from Mercedes and delivered up to 30 horsepower. Ariel also experimented with six-cylinder models that could produce up to 60 horsepower, but none became enormously popular. After 1918, the company made one last attempt to capitalize on the small-car market with the Ariel Nine. When the original Atom was launched in 2000, it was the first vehicle to bear the Ariel name in 27 years.


The Atom in America

Image courtesy Brammo Motorsports / Ariel Atom

In the United States, the Atom is available through Brammo Motorsports, an Ashland, Oregon-based company that specializes in manufacturing niche production vehicles for the North American market. Brammo was founded in 2002 and currently employs 27 people. Brammo CEO Craig Bramscher became interested in the Atom after taking the car for a test drive. When Ariel started looking for an American dealer, Bramscher felt that Brammo was a good match. After evaluating several companies, Ariel agreed and entered into a licensing agreement with Brammo.

Full North American Specs for the Atom
  • Engine: General Motors Ecotec 4-cylinder
  • Displacement: 1998cc
  • Maximum Power: 205 horsepower with base trim; 245 horsepower with tuning; 300 horsepower with tuning plus supercharger
  • Maximum Torque: 200 foot-pounds
  • Transmission: Five-speed manual
  • 0-60 mph: 2.8 s
  • Maximum Speed: 135 mph
  • Weight: 1005 pounds
  • Weight-to-Power Ratio (lb/hp): 4.9 to 1 with base trim; 4.1 to 1 with tuning; 3.35 to 1 with tuning plus supercharger
  • Fuel Economy:33 miles per gallon

As mentioned earlier, Brammo's version of the Atom specifies a General Motors Ecotec engine instead of the Honda iVTEC specified by Ariel. Otherwise, Brammo adheres strictly to the vision of Simon Saunders, handcrafting each car one at a time. Brammo has six vehicles already built, with 50 on order. Ten potential customers fly in for test-drives each month. In five years, Brammo plans to be making a thousand cars -- and $80 million -- annually.

Brammo's aspirations don't end with the Atom, either. Lead Designer Brian Wismann, a veteran of Daytona racecar body designing, is hard at work on Brammo's own line of specialty vehicles. One of these is the Brammo Rogue GT, the first V12 American supercar designed and built in the U.S. for the world. The company also has plans for a V8 supercar, priced under $200,000, that will be marketed under the name Ronin GT, as well as an environmentally friendly electric vehicle and an alternative-fuel racecar that runs on liquid propane or hydrogen.

So will we see Atoms zipping by us on the interstate or throwing back a cloud of dust as it barrels down a country road? It's not likely -- the Atom will probably be a rare sight on the highway. After all, it is only street-legal if assembled as a kit vehicle, and there are only a few registered Atoms in the United States. As a turnkey vehicle, the Atom is sold as off-road-only for track-day use. And it's there -- on America's tracks -- that the Atom will continue to break records and leave jaws hanging on the ground.


Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Ariel Motor Company Web Site (UK)
  • Ariel Motor Company for USA
  • Bailey, Shaun. "Ariel Atom: Going nekkid." Road & Track. February 2006.
  • Brammo Motorsports
  • Darling, John. "Very hot rods." Oregon Mail Tribune. January 11, 2006.
  • Erjavec, Jack. "Automotive Technology: A Systems Approach." New York: Thomson Delmar Learning. 2005.
  • Lyons, Pete. "Zany Prodigy." AutoWeek. February 19, 2006.
  • Phillips, Adam. "Supercars: Driving the Dream." New York: Barnes & Noble Publishing, Inc. 2006
  • Sanew, Mark. "The Ariel Atom meets the USA." August 31, 2005.
  • Weaver, Alistair. "Ariel Atom: Honda-powered road-legal racecar." May 11, 2006.