Debunking

Last year, I bought Masato Abe’s Vehicle Dynamics and Control. It’s the third edition, published by Tokyo Denki University Press. I already had the second edition from Sankaido, but I heard that the contents had changed quite a bit in the February 2025 revision, so I wanted to read the new edition and ended up … Read more

One common explanation of the friction circle that you often hear goes something like this: “The friction circle isn’t a perfect circle, but is closer to an ellipse that is elongated in the vertical direction. In other words, tires can generate more force longitudinally than laterally.” I don’t even know what my reasoning was, but … Read more

You may have heard the term “short-stroke modification” come up from time to time when people talk about suspension. It seems to be commonly done to prevent the spring from becoming unseated after lowering the ride height, but what exactly does it involve? Today, I’m going to show you, with some diagrams, what happens to … Read more

When it comes to how springs work, I think most of you are probably familiar with the relationship between load, spring rate, and displacement, and may have even calculated it yourselves at some point. But figuring out how fast a spring moves is probably not something most people are familiar with. Because of that, you … Read more

The other day, I was watching a video explaining what happens to roll center when you lower a car, and something caught my attention. The basic argument is, “People say lowering the car messes up the roll center and all that, but in reality, you’re also running stiffer springs, so you don’t really need to … Read more

There is something I occasionally see written about tender springs that has always bothered me. “With a lower spring rate, the suspension has less force pushing the wheel outward, so less load remains on the tire.” Isn’t that actually the opposite of what happens? Rather, when the front and rear spring rates are different, the … Read more

As we discussed in the previous article, this article continues our discussion of response. Roll stiffness and body stiffness are both important, but tire stiffness is also a key factor. Have you ever tried attacking a circuit on eco tires or comfort tires? Compared with tires designed for motorsports, these tires have lower stiffness, and … Read more

Think about this. Suppose you take a car with its stock suspension, put high-grip tires on it, and take it to the track. The car rolls so much that its response feels slow and it’s very difficult to drive. What would you do to make the car easier to drive? Increasing the damping force will … Read more

If you’ve ever driven on a racetrack, there’s a good chance this question is always sitting somewhere in the back of your mind:“What’s the fastest way through this corner?” In Japan, there’s a legendary professional racing driver named Motoharu Kurosawa. If you ask who has had the greatest influence on circuit driving in Japan, his … Read more

Most of you are probably familiar with the friction circle, but a few years ago… I came across an article about it on the internet. It was written by an individual. ——————————————– A tire’s grip has a limit. If you use 100% of the available grip in the longitudinal direction, then you cannot use any … Read more