In this article we are not only going to learn how to calculate load transfer in a vehicle, but more importantly, learn to visualize how the forces are acting between the car and the tires. Understanding these forces becomes very important when we move on to articles dealing with car balance, roll centers, and almost all things suspension related. If you haven't read our tire science article, make sure to go through that first, particularly the section on load sensitivity, as we will be using those concepts here.
Head instructor and author Adam Brouillard takes you through a lap of Lime Rock Park in the iRacing Global Mazda MX-5 Cup car.
In this video, author Adam Brouillard discusses the physics of the racing line.
The center of gravity (CG) of an object is its center of mass by which all acceleration forces act through. It’s an imaginary point where if you could suspend the object from that location, it would be balanced in all directions. In a kart, this point is generally somewhere right in front of where the driver sits. Since the driver is such a large percentage of the overall weight of a kart, moving around a lot can cause the center of gravity to also move around by a significant amount. Some karters will actually move on purpose to alter handling. For instance, you could lean back as you brake to put more weight on the rear tires to allow improved braking.
Seemingly simple, but surprisingly complex, kart racing is as full of secrecy as it is misunderstanding. This leaves many curious karters searching for real answers. We don't much like secrecy or misunderstanding so in this two-part article we will look at the unique considerations of karts. Even if you aren't the solid-axle sort however, learning about karts can teach you a lot about the more "advanced" racing classes.
We have some upcoming articles where a basic knowledge of how tires work will be needed so we've put together a brief overview. Tire science is incredibly complex, but there are certain aspects that can be quite important for a racing driver to understand. In this article, we will go over load sensitivity, slip angle and induced drag, as well as slip ratio.
As a supplement to our Racecar Setup Guide, we've created a flowchart to give those newer to car setup a starting game plan to follow. This chart represents a good basic setup philosophy that covers the primary elements that affect vehicle handling and performance. It will give a driver something to build on and tailor to their own needs as their vehicle dynamics knowledge expands.
This flowchart shows a balance-based approach where no advanced telemetry or tools will be needed. A driver will primarily use their ability to detect understeer and oversteer to work toward a good setup. This is an approach that will grow with driver skill and as you become more sensitive to car balance, you will be able to hone in on a better and better setup.
This is a follow-up to our previous article about reducing motion sickness in sim-racing titles. The topic of whether or not the view should be locked to the horizon in sim-racing titles was hotly debated when it was first introduced years ago and this sim-racing civil war has not in any way subsided. We wanted to write this follow-up to shed some more light on the subject and hopefully bring about a ceasefire. We'll first go a little more in-depth into the the science and then talk about the pros and cons of horizon locking as well as how each individual might want to use it.
Note: We have created a follow-up article with more info about the pros, cons, etc... here. We're big advocates of sim racing as a motorsport in its own right and also as a great training tool for real world competitors. For many racers, virtual reality has brought sim-racing to a whole new level and you hear many stories of elation from drivers after donning a VR headset for the first time and experiencing the cockpit of their favorite exotic sportscar as if they are really there. For some however, that elation is short lived once they pull out onto the track and the first few corners make them start to wonder if they might be seeing their lunch again soon.
We've put together a quick-reference infographic of the racing line covering the whole apex spectrum. From the lowest-acceleration early apex to the fastest late apex. Virtually every vehicle would ideally travel somewhere between these two lines.
The graphic covers everything from turn-in points and apex angles to the appropriate steering, throttle, and braking needed along the continuum of apexes. You'll learn what kinds of corners and cars need earlier and later apexes as well as the key differences as your apex angle moves along the inside of the track. See how cars capable of high-acceleration in a corner need a later, slower turn-in and a slower, tighter radius to more effectively use their power during corner exit.
We use the term Line Theory for the physics-based set of rules a driver can use to work toward an ideal line on a racetrack. This is great for those drivers who have hit their wall or at least have a few events under their belt and can get around a track somewhat competently. It allows a driver to slowly chip away at their mistakes as they reach ever closer toward their ultimate potential.
This guide will give you a procedure to follow to start optimizing the setup on virtually any car. So as not to fill the guide with repeated information, it is assumed the reader has a basic knowledge of racing and setup terms. Readers may want to look through our Racing Terms Glossary first. This guide is primarily aimed at road course racing in cars, but will have some use for kart and oval racing as well. Also, understand that learning vehicle dynamics and setup can be a very complex subject. This guide is simply a jumping off point to hopefully get you in the proper mindset for learning about car setup and we are glazing over a lot of the background information needed to truly understand the "why.”