Mechanisms

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

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

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

When it comes to suspension arms, you often hear people say that longer arms are better. But is that really true? Intuitively, it seems like longer arms should result in less change in the camber angle, so it’s easy to see why people think they’re better. Today, let’s take a look at the specific effects … Read more

Load transfer is important in circuit driving, right? Although its importance is widely recognized, both from a driving and mechanical perspective, I think relatively few people have actually calculated how the load on each individual wheel changes as a result of load transfer. Compared with something like calculating damper stroke at 1G, calculating the amount … Read more

Have you ever heard of circuit simulation? It is a way of calculating how fast a car can theoretically lap a circuit, based on the car’s performance and the racing line. The circuit simulation I’m introducing here was created by Tatsu. According to him, it was “based on the F-1 Circuit Simulation published in the … Read more

I was just wondering: when did the term “roll center” become something that even ordinary car enthusiasts started hearing about? When I first became interested in suspension, I was at the level of, “What’s the difference between a spring and a damper?” So, naturally, I had no idea what a roll center was. These days, … Read more

Do you guys drive on circuits, compete in gymkhana, or go on mountain road attacks? When you think, “I want to go even one second faster!”, you might start adjusting your coilovers to tune steering characteristics such as understeer and oversteer. You’ve probably heard things like making the front springs stiffer will cause understeer, or … Read more

There are countless factors involved in suspension tuning, and I certainly don’t know everything about all of them. Damping force, suspension bushings, differences between spring manufacturers, preload, bump stops, anti-roll bars, alignment changes through suspension travel, compliance steer, roll centers… and of course, vehicle weight distribution also plays a role. Once you start including tire … Read more