I've been asked several questions about cars and motorcycles over the years. However, it was a question by a 7-year-old that left me wondering too. Recently, my nephew, Dylan, asked me a simple question — why do cars have four wheels, Uncle Joe?
I'll be honest; I didn't know the answer just then. Do you know the answer? I would be interested to know your thoughts. For now, here's my take on why cars have four wheels. Why just cars, think about it — tables, chairs and beds, all have four legs as well.
It's all about weight distribution. To ensure good weight or stress distribution, it is best to load a structure at its endpoints. Think square or rectangle. How many end points — four, right? So, squares and rectangles get four support points. Hexagons, on the other hand, get six supports, and triangle shaped objects like an aircraft must get at least three.
Also, the chances of a three-wheeled motor vehicle flipping over while taking on a sharp corner is more probable when compared to a four-wheeled motor vehicle, and any odd combination leads to additional requirements from a functional point of view.
Try going flat out in a tuk-tuk on a sharp corner, or how many of you've watched — Rolling a Reliant Robin — Top Gear episode. A three-wheeled vehicle is more vulnerable to tip going around a curve that can add as much as 4X the amount of weight shifted to any one wheel and therefore make it easier to flip over.
It's not like there haven't been any three-wheeled motor vehicles? Take the Polaris Slingshot, a three-wheeled motor vehicle. Polaris prefers calling the Slingshot as "a three-wheeled motorcycle!" But, with three wheels comes compromise such as: space, comfort, packaging, speed, and performance.
Apart from weight distribution, another important factor is traction and balance. A four-wheeled car will have better grip and proper balance, which allows for improved handling response.
Overall, if you want to enjoy your drive — a car requires proper weight distribution, traction, and balance, and that is why Dylan — a car needs four wheels. Happy Motoring Ahead!