Dimensions

A Car’s Performance is Dependent on Its Dimensions and Weight

A vehicle’s frame and the basic layout of its operating parts are the most basic specifications, and are decided during the initial stages of development, making them the hardest to change later on. These specifications have a crucial effect on the three main functions of driving, turning, and braking. Any deficiencies are difficult to compensate for with tuning, and just a slight difference can have a huge effect on performance. Furthermore the effect gained from tuning are also greatly affected by the car’s base potential. To get the most out of your car, you should be familiar with how these basic specifications affect driving performance.

Wheelbase

The wheelbase is the distance from the center of the front wheels to the center of the back wheels when viewing the car from the side. This length has a large impact on the stability of the car. The longer the wheelbase, the less affected the vehicle will be by undulation of the road surface and crosswinds, and it will tend to be more stable in a straight line. On the other hand, although a shorter wheelbase reduce stability, steering responsiveness is improved, and the car will be agile around corners. In terms of comfort, a longer wheelbase is generally considered better

Overhang

The front overhang is the length of the car that extends beyond center of the front wheels to the foremost end of the front bumper. Rear overhang is the length of the car that extends beyond the center of the rear wheels to the end of the rear bumper. If the parts of the car in this overhang are heavy, the yaw moment of inertia (resistant to turning) increases, and maneuverability is reduced. Because of this, components of a car with significant weight should be placed within the wheelbase whenever possible. This is especially true for heavy components such as the engine. However, an overhang of some length is important for aerodynamic purpose, so it cannot be avoided altogether.

Track Width

Track width refers to the distance between the left and right wheels of a car. Increasing track width will lower a vehicle’s center of gravity. Generally speaking, increasing track width improves traction when cornering, and increasing the track width of the drive wheels will increase contact with road surface, and thereby improves the vehicle’s ability to transfer its power to the road surface. A smaller track width, on the other hand, will offer quicker handling, but will reduce stability. It’s common for racing cars to have different track widths for the front and rear wheels to improve handling.

Height

Height is measured from the road surface to the highest point of a vehicle. Lower heights means a lower center of gravity, reducing roll when cornering, and increasing turning speed. However, lower height also means less room for passengers and shortened suspension stroke (the amount of room that suspension springs have in which to expand and contract), and increases the risk of bottoming out of the suspension.

Weight

Weight is a crucial factor in determining vehicle performance. The lighter the car, the less demand on the engine, and the more power can be used for the movement. Other benefit include reduces brake wear and more efficient cornering. The weight of a car divided by its maximum power output is known as the power-to-weight ratio. The smaller this ratio, the faster acceleration will be, and the sportier the ride. This also has a major effect to fuel economy, and reducing the weight of a car is now an important factor in designing new cars in term of environmental impact and performance.