aki@rs

Secondary Springs: How They Work and How to Set Them Up

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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

Drivers and Engineers

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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

Learning to Learn

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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

How Roll Axis Setup Affects Handling

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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

How Suspension Travel Affects Tire Performance

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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

Comparing Camber Changes

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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

Using Bump Stops to Increase Traction

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When setting up rear-wheel-drive cars, I sometimes hear people say that they use bump stops at the rear to gain traction. I used to think, “If the rear hits the bump stops and that increases the rear suspension’s effective spring rate, wouldn’t that actually reduce rear tire grip?” I couldn’t really make sense of it. … Read more

The Factors That Determine Load Transfer

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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

Is the Friction Circle Really Longer Longitudinally?

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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

Does Short-Stroke Modification Really Make Bottoming Out Less Likely?

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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