Categories
Chassis Heeltoe Explains

What is the “Chassis?”

When speaking about the vehicle as a whole, the chassis is the first major component that is considered. The frame or unibody is the large structural unit that is the base of the vehicle’s assembly. The wheels, suspension, body, engine, and other vital parts of a vehicle all must attach to a base assembly; referred to collectively as the chassis.

Rolling Chassis

There are differing opinions as to what is included in a rolling chassis. Some sources include an engine and drivetrain nestled within an otherwise bare vehicle frame. Others claim a rolling chassis is more of a complete vehicle without the drivetrain; which is not accurate as a rolling chassis would not necessarily include any coachwork or comfort items. Body-on-frame cars are easier to visualize as a rolling chassis; it’s the vehicle with the body removed. An engine need not be part of the package as long as the suspension arms, dampers, springs, and hubs are there, along with brakes and wheels.

Chassis versus Frame

To state a chassis as “the frame” may be an over-simplification of what a chassis is. The frame is the major component of the chassis; it acts like a skeleton that provides the backbone of the vehicle. To it, suspension arms with spindles, brakes and wheels are attached. As components are added, the frame becomes a chassis. To put it another way, the chassis is the pure functional component assembly without the body on it.

Chassis versus Shell

It becomes difficult to nail down where the chassis stops and the body starts when the vehicle has a uni-body construction. In these chassis configurations, the body shell serves as the frame. As such it is not practical to visualize the frame without the body. With the aid of auxiliary sub-frames that are affixed to the uni-body, suspension arms are attached to the body, to create a rolling chassis. Commonly, people will refer to this chassis as a shell or a rolling shell. While the body is present, the interior usually would not be. Again, the powertrain is “optional.”

Categories
Brakes Heeltoe Explains

What are “Brakes?”

This brief article is going to explain the different components of modern automotive braking system parts including pads, rotors, calipers, drums, and more. We have written article because customers often as for “new brakes” but only seem to be talking about certain parts. Basically, this article is here to help you understand more about how the system works, and therefore are better equipped to shop for parts.

Brakes aren’t the round metal discs behind the wheel. Nor are brakes the parts that wear out and squeak.

“Brakes” refer to a set of components that work together to bring a vehicle to a stop once it is moving. Braking systems on most modern vehicles are hydraulically actuated. The brake pedal acts on a master hydraulic cylinder which, usually with the assistance of a vacuum-powered booster, pressurizes a hydraulic line and actuates cylinders at each wheel. A proportioning valve controls the bias of pressure to all four corners.

The cylinders at each wheel actuate either pistons in a caliper (for disc-brake applications) or a wheel-cylinder (on drum brakes). In disc brakes, the caliper pistons push on brake pads that have friction linings. These linings are forced against brake discs, or rotors, which turn with the vehicle’s wheel hub. This force slows the turning of the wheel and slows the vehicle.

Drum brakes work similarly with different components. Wheel cylinders push brake shoe-linings against the insides of a drum that spins with the wheel hub to slow the vehicle. Drums on modern cars are used in rear applications, if at all, and are mainly used for cost savings in low-demand applications since disc brakes are much more efficient at stopping vehicles.