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Volvo: Safety Beyond the Star RatingsWhat is a Car Chassis?
In this article we take a deep dive into car chassis. The chassis is the biggest and strongest part of your car and yet many have never heard of it.
If You’ve Got a Car, It’s Got a Chassis
In a world of exceptions to the rule, it’s hard to say that every car has any one singular feature but it’s true of the humble chassis. Regardless of era, country of origin, or segment, every car has a chassis, also called a frame, of one sort or another.
That’s not to say though that every car has the same type of chassis and today, we’re going to break down some of the most popular. We’ll cover what a basic chassis does, how chassis design has improved over the years, and take a look at what modern innovations have allowed the chassis to be better than ever.
Basic Elements of a Chassis and What it Does
At its very core, the chassis itself is the core of a car. By that, we mean that the entire car connects to the chassis in one way or another. It’s often been likened to the skeleton and its alternative name, frame, alludes to the idea that it’s the framework on which the rest of the car comes together. All of the major components in a car, truck, or SUV attach to the chassis.
Because of that, chassis design plays a large role in how a car handles, how strong it is with regard to torsional rigidity, and can heavily influence body panel design too. Chassis also have to be strong enough to deal with the forces exerted on them by the road, the drivetrain, and the people and cargo that they carry.
A Quick History Of Chassis Design
In the earliest cars, chassis design followed the principles originally crafted for wagons. As such, they were little more than rigid structures with mounting points for the steering, wheels, seating, and drivetrain. While they were often crafted of bent and welded steel tubes they mostly looked like what we call a ladder chassis today.
Ladder frames get their name from their general resemblance to the climbing tool and they benefit from a simple but usually quite sturdy design made up of two main beams along with a number of cross beams connecting the two. The engine, suspension, and body would all attach to the ladder chassis in their own way.
In the early 1900s, automakers began experimenting with a new type of chassis called the backbone chassis. As its name suggests, it used a singular beam stretching from the front axle to the rear axle to support the rest of the vehicle. Variations that combined the ladder and backbone chassis ideas exist too.
In the 1920s, Lancia developed the first unibody chassis which integrated the frame along with the body and the floor pan into a single structure. Not only did this make the vehicle lighter but it normally made the eventual car stronger too. Today, unibody construction makes up a vast share of the automotive market.
By the 1930s, automakers were leaning back into the idea of tubular or spaceframe chassis. In such frames, no singular structure or pair of structures makes up the bulk of the strength. Instead, an interconnected network of tubes provides strength. In addition, whereas most ladder and backbone chassis required the cab to be built atop the frame, tubular chassis typically surround the occupants to one degree or another which, in turn, often increases safety.
For the most part, modern cars are made with ladder frames or unibody chassis but let’s take a deeper dive into modern engineering.
Modern Chassis Engineering
Today, technology allows automakers to develop, engineer, prototype, and manufacture faster than ever before. To that end, huge advancements have been made regarding both ladder frames and unibody construction so as to allow each to be stronger, safer, and more adaptable to different vehicle types.
Most often, unibody designs are found in everyday passenger cars, crossovers, and some smaller SUVs. Ladder frames are still the popular choice for trucks, larger SUVs, and especially those that are built to go off-road or tow heavy loads. A few newer chassis designs have come online too.
The monocoque chassis takes its name from the French word for “single shell”. As that name implies, it leverages parts of the body itself to create and maintain structural integrity. Today, it’s often crafted into a single piece and the rest of the car is built around it. It’s been around for a long time but is rarely used in the production of road-going vehicles. It’s very popular in racing and in high-end super sports cars because it’s light and strong.
Finally, the future of the automobile seems destined to be on a skateboard. No, not the type you ride on but the type automakers now use for the underpinnings of electric vehicles. A skateboard chassis does look like the type you’d grind rails with though. It integrates the battery pack for an electric vehicle underneath the floor and connects both sets of wheels along with whatever body and motor are called for. As a result, the skateboard chassis is very modular and can be changed as needed to suit longer or shorter cars.
