The Setup Process

A systematic approach to producing a workable racing chassis setup is best. This chapter explains how I go about the process.

In the iRacing game, there are three ways to build a setup:

  1. “Guess and check”: Keep making adjustments until it feels right.
  2. “Egg hunting”: You’re looking for Easter eggs. You’re looking for flaws in the garage or setup engine that produce fast, if not unrealistic, results.
  3. Technical accuracy.

I’m looking for #3 here, and to do that, I’m using the numbers iRacing is giving me to dial in the car – sometimes in spite of what the drivers are telling me. The numbers almost always win. The “numbers” I’m looking for come from either the “Tires” page in the garage, or (for more advanced setups) telemetry. In all cases, testing involves:

  1. Drive 15 miles.
  2. Make the chassis adjustments.
  3. Use the tire temperatures to diagnose and assess.

In my case, I use telemetry, but the garage view will work to some extent also.

Naming Conventions

Your setup files are kept in per-car folders in the %USERPROFILE%\Documents\iRacing\setups folder in your computer. You can press [Windows Key] + [R] to open the “Run” dialogue box; then paste that right in to get there in a hurry.

Some racers use simple filenames like Chicagoland v3. This will cause problems down the road because you won’t know what year or month (i.e., which iRacing build) you’re dealing with there. More descriptive filenames are more helpful. I use a naming convention like this: cup-chicagoland-2021-05-test-013 - it includes the car, track, a date, whether it is a “race,” “test,” or “qual” configuration, and a revision number, so I can always go back to a previous setup in case I’ve done something stupid.

Chassis Adjustments

When making adjustments to the chassis, follow the steps outlined below. Some adjustments, such as the track bar or minor spring perch (shock collar) changes, do not need the anti-roll bar (“ARB”) steps to be taken and with experience, you’ll get a feel for when detaching the ARB helps stabilize the chassis during your setup adjustments.

  1. Unwind the front and rear ARB preloads and then detach (uncheck) them; click “Apply.” You may wish to note these values first.
  2. If the rear ARB cannot be detached, get it to as close to zero as possible (-1.9 through +1.9); click “Apply.”
  3. Make one single change at a time (or a pair of changes, if symmetrical changes are appropriate); click “Apply.”
  4. Re-attach the front and rear ARB’s and dial-in the preload specified (if appropriate); click “Apply.”
  5. Make a final rear truck arm preload adjustment by getting it to as close to zero as possible (-1.9 through +1.9) and re-attach the rear ARB if applicable; click “Apply.”
  6. “Save As…” your setup with a unique version number each time you change things; example: cup-chicagoland-2021-05-test-012; then cup-chicagoland-2021-05-test-013; etc.

The previous sections of the guide explain key setup concepts that you will now apply as part of the setup process. Refer to the appropriate chapter for specific instructions and guidance on each step of this process. The next section (“Troubleshooting”) shows the kinds of changes you can make to address specific handling issues and scenarios. For example, the most common chassis complaint is tightness from the middle through the turn off (while tracking out); or “plowing down the wall.” The “Troubleshooting” section says “Car wants to plow (understeer) under hard acceleration (turn exit)." The primary fix for this problem is to increase the spring stagger at the rear of the car; which means, soften the left rear spring and/or stiffen the right rear spring. Since stiffening the right rear spring ALSO address the issue of “Car wants to plow (understeer) when coasting through a turn”, that’s the fix. The one single change would therefore be to add spring rate to the right rear.

Remember to check your ride heights (using the spring perches, also called shock collars) after making your changes!


Each time you make a chassis adjustment, you must test the car for 15 miles on-track to see what the change did. Sometimes, you know RIGHT AWAY that your change went the wrong direction, and you can shorten the test run.

Follow the steps below, using tire temperatures as a guide (See Chapter 4.), to make your adjustments:

  1. Run 15 miles (usually 10 laps, ~5-minutes).
  2. Adjust front cambers, if needed. See Chapter 4.
  3. If cambers changed, repeat from step 1.
  4. Adjust tire pressures, if needed. See Chapter 4.
  5. If tire pressures changed, repeat from step 1.
  6. Adjust front toe, if needed. See Chapter 4.
  7. If toe changed, repeat from step 1.
  8. Adjust wedge (e.g., left side spring rates, spring perches), if needed. See Chapter 3.
  9. If wedge changed, repeat from step 1.
  10. Adjust for tight or loose condition (e.g., roll couple distribution: right side spring rates, spring perches), if needed. See Chapter 3.
  11. If tight/loose adjusted, repeat from step 1.
  12. Adjust for the most over- or under-heated; or over- or under-worked tire, if needed. See Chapter 4.
  13. If chassis adjusted for tire workload, repeat from step 1.

Just keep running 15 miles (usually 10 laps) until no adjustments are needed based on garage tire temperatures, pressures, and averages. The process usually takes about 2-3 hours to get a setup “close” with as many additional laps as you like making tinier adjustments. Real good setups usually take 8-12 hours, but by then, only the most competitive drivers and teams haven’t exceeded the point of diminishing returns. At a certain point, you have to decide when it’s “good enough” because at the end of the day, it’s not so much the setup that determines your races outcomes. You still have to drive the setup; you still have to avoid the wrecks. You really only need a setup good enough to give you the tools to race well.

Coming soon: Online tire temperature analyzer! This implementation of the Pyrometer Tool will look at your tire temperatures for you, and tell you exactly what changes need to be made! Until this tool goes online, use the information in chapters 3 and 4 of this guide to inform your decisions.


Although you can achieve a high degree of success just using the tire pressure and temperature information in the garage, using telemetry to deep dive into the setup produces more accurate results. How to install, record, and analyze telemetry will be a future topic for the website.