[GForceEnjoyer]

I came across this absolutely beautifully detailed article explaining why an overwhelming majority of car wheels today are quite flat in design, when compared to much older cars from many decades ago. It's the first time I've come a step closer to understanding what the scrub radius and kingpin axis means. Thought it'd be an interesting read.

Years ago, in days of old, cars came with wheels that had very deep dish styling. Over the years, as technology marched on, deep dish wheels got shallower until finally, starting about 20 years ago, they became essentially flat on the outside. Why did this happen? Well, in a word, “steering” is what happened. The change from deep dish wheels to flat wheels can be traced back to improvements in the steering system — in particular, to the popularity and advantages of rack and pinion steering.

The article also dives deep into the history of the steering system and why older systems actually benefited from a large scrub radius. Then, with the advent of rack and pinion steering, all this changed for a host of reasons covered extensively by the article. Finally, housing the braking system and ensuring aerodynamic efficiency also causes the ideal wheel designs to be quite flat.

Source: The Autopian.