Understanding vehicle dynamics through curiosity, not myths.
aki@rs I wrote an article about the definition of the roll axis last time. We talked about how, strictly speaking, it may not be appropriate to call “the line connecting the front and rear roll centers” a roll axis when that line is inclined relative to the x-axis. But the angle of the line connecting the … Read more
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
Motorsports are a little different from other sports, aren’t they? More than anything, the difference that equipment can make is huge. I think every sport that uses equipment has some degree of difference between the tools people use. In swimming, it could be the difference in drag between swimsuits. In track and field, it could … Read more
The Psychological Trap of Entering a Corner Too Fast When I watch YouTube videos where professional drivers explain circuit driving, I often hear comments along the lines of, “Amateurs and beginners tend to lose a lot of time simply by entering corners too fast.” I thought, “Surely I must have made this mistake too,” and … Read more
The red part represents the anti-roll bar, the green parts are the anti-roll bar links, and the gray plate-like part represents the lower control arm. When the suspension moves through its travel, the anti-roll bar moves like this, and the lower control arm moves like this. It kind of looks like a bird’s wing… Flap, … Read more
When you hear the term “secondary spring,” what comes to mind? There are several types of secondary springs, including helper springs, tender springs, and primary springs. Here, I use “secondary spring” as a general term for a spring that is used in combination with, but separately from, the main spring. For example, a 20 N/mm … Read more
An engineer from Team Le Mans, a racing team that has competed for many years in top Japanese categories such as SUPER GT and Super Formula, once wrote the following in a post published on the team’s Facebook page: Does changing the springs change the amount of load transfer under braking? No. It doesn’t matter … Read more
The other day, I came across a thread on X that really resonated with me. The author argued that self-study has actually become harder in the age of the internet. Beginners naturally search for answers online, but because they don’t yet have the foundation to judge what is important—or even what is correct—they tend to … Read more
Every now and then, you hear people say something like this: “That car has a front-downward roll axis, so it has sharp handling.” It’s true that as the roll axis slopes downward toward the front, a car tends to become more oversteer-oriented. Tilt it the other way, and it tends to become more understeer-oriented. But … Read more
Hello everyone! Quick question: have you lowered your car? As a responsible MX-5 Miata owner, I still have enough self-control not to slam it completely. That said, if it were up to my emotions, I’d slam it straight into the ground. When I was younger, I remember someone I knew who did time attack saying, … Read more