This setup guide is geared towards paved oval race car chassis setups. In the future, we may add content to address other setup disciplines. Stay tuned!
Building a setup is a systematic process. There are some rules to follow; and unfortunately, some rules to be broken. Nonetheless, I have researched sim racing setup documentation from various sources (plus some real-world setup materials) for oval racing and have experimented with various processes. I have discovered a few key points:
- Real-world setup principles are implemented in the sim racing garage to a high degree, so they work.
- iRacing telemetry is more reliable than driver feedback when debugging a setup; it’s the numbers out of iRacing, which means it’s the numbers that iRacing “wants to see.” Break from this principle only when a “garage bug” which gives you tremendous speed is discovered. They’re out there: Happy Hunting!
- Setups that are fast early on usually fall off quickly and end up being slower during a long green flag run.
- Long-run setups are usually a bit slower early on, but then “come in” mid-run and remain competitive during a long green flag run.
- Faster setups are usually a handful: They require a higher degree of skill to master and even in experienced hands, can be a primary contributing cause of racing incidents.
- Slower setups are usually very ergonomic: They are easy to handle and in fact a joy to drive over the course of the race. Comfortable setups like these almost never cause mysterious losses of control or racing incidents.
The takeaway: Setups are a game of trade-offs. Short-run vs. long-run usually becomes a part of this conversation and can dictate the flow of your race in the form of a gamble: Will there be lots of cautions? Or will there be lots of green flag runs? As a driver, do you want to keep chasing your faster setup? Or would you prefer a comfortable car that won’t tire you out during a long full-length race?
Using This Guide
This guide is organized into chapters. Read through them to learn about the setup topic. Apply that knowledge when actually building your setup in the “Setup Procedures” chapter; this is where the actual “testing” takes place. While testing and making garage adjustments, you can then refer forward to the “Troubleshooting” section to discover what changes fix setup defects; or refer back to the earlier chapters to learn and understand how those setup changes work scientifically.
The rest of this chapter explains the basics of setup building. You could skip forward to the “Setup Procedures” section and get right into it! However, you won’t really understand what is happening unless you take the time to study the contents of this complete guide.
Note that this guide is a “living document” which will be revised and updated as I make evergreen discoveries while setup building, or learn new concepts from the community. Please visit our Discord server for up-to-the-minute information, and come back to the guide often for new content.
The Starting Line
Begin the setup journey with a baseline setup. This could be a “fixed” setup for a similar car and track, or perhaps an existing setup from another teammate, racer, or friend. Perhaps you’ve purchased a setup from a commercial setup builder? Test this baseline setup and grade its performance, taking care to subjectively evaluate the following performance metrics:
- Is the car generally stable (tight or reluctant to turn) or unstable (loose or keen to spin)?
- Is the car tight or loose under heavy braking (especially when entering a turn)?
- Is the car tight or loose when rolling a corner (how does it behave between turn entry and turn exit, when you’re rolling the bottom)?
- Is the car tight or loose under acceleration (especially when exiting a turn)?
These four fundamental questions, when tied together with skillful analysis of the collected telemetry data, will steer you right into the perfect setup for your car, track, and driver.
Initial Setup: Ride Height
The very first task when building a setup is establishing the car’s ride height. If you’re starting with a built-in setup or a commercially built (paid) setup, this should already be done for you. I have had very good results from using paid setups as a starting point; they are usually very close to what I want, and the ride heights and spring rates are usually very close to perfect.
Ride height will determine whether you have a car optimized for straightaway speed (superspeedways, longer ovals) or for greater turn performance (shorter tracks). You can correct the general stability of the setup while you establish your ride heights, especially with respect to the truck arms, which will be a permanent setup item that you’ll want to establish right away, and which determine how a car handles braking and entering (heavy breaking into a turn) and, more importantly, the turn exit characteristics.
Chassis Control: Spring Stiffness
Once you’ve established with some certainty what you need for a ride height, you will maintain that ride height while fine-tuning your car’s turn performance. MOST IMPORTANTLY, firmly establish turn exit performance. This is definitely your objective, since it determines how long the straightaways take to traverse – and since these are the fastest sections of every track, turn exit should be your primary setup objective.
To achieve the right ride heights, you’ll be working with springs and spring perches. These setup items also affect the handling of the car during a race: Loose, neutral, or tight under braking or throttle lift (deceleration)? Loose, neutral, or tight while rolling the bottom of a turn (called the turn’s “apex”)? Loose, neutral, or tight while throttling out of a turn (acceleration)? The spring stiffness at each corner of the car contribute greatly the behavior of the chassis in these driving situations. Much of your setup building will be understanding how to correct any defects in the handling of the car while maintaining the same aerodynamic ride heights, so understanding the chapter on “Spring Stiffness” may well be the most important chapter in this entire guide.
Fine-Tuning: The Finish Line
Once your chassis tuning gets past ride heights and the initial spring rates, you’ll get down to the nitty-gritty and the hardest (and most important) part of the setup: Testing. This is where you’ll “dial in” the race car chassis for speed, stability, and long green flag runs. The chapter on the “Setup Procedures” explains how to systematically approach testing.