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Gaining Speed in your Setup

The basis for every fast setup is aerodynamics!

Using Motec to analyze what your setup is doing is a MUST if you take iRacing seriously. This is a tool you can use to watch all kinds of in-detail things your truck is doing. In order to use the software, you will need to turn on telemetry saving by pressing ALT+L in-game.

Once the telemetry is saved, it needs to be decoded by software. For this software I use Mu which converts the iRacing telemetry file to use with Motec. I will link Motec and Mu at the bottom of this page.

Once you have them downloaded you need a workbook to display the information neatly and organized, I will link my workbook at the bottom as well. 


Now that's done, lets discuss making your truck faster!

There is a lot of speed in aerodynamics alone, even at the short tracks. Sealing your splitter on the ground is crucial for any speed. The more level and lower the splitter = more speed.


Keeping the splitter as low as possible through the corners and down the straight away is harder than it looks. The easiest way of lowering the splitter is by coilbinding. The C Class Craftsman Truck Series thankfully are really easy to coilbind. I prefer coilbinding off of the LF spring.

To do this, set both front springs to 300lbs. Make sure both front ride heights are as close as they can go without failing tech (4.750). Run one lap with your telemetry on and log your ride heights in Motec. Increase the LF spring by 10lbs and run another lap, you will notice that the splitter is consistently lower throughout the lap. Congrats you're coilbinding! You will want to increase this spring rate until your splitter hits the ground. This will ensure that the maximum amount of air that is going over the truck onto the spoiler as apposed to under the truck causing turbulence and a loss in downforce.

Beware that your splitter height will change if you change the following:

Crossweight - Rear Springs - Rear Ride Height - Sway Bar Slack - Front Ride Height

Setting Rear Skew

Rear Toe

Courtesy of

Setting the proper rear skew is essential for long run and short run speed. By changing the rear toe you change the sideforce of the truck. You always want your rear toe going in opposite directions (+ and - for anything under 2 miles) and (- and + for anything over 2 miles).

In the picture to the right, you can see what positive skew looks like, where the rear end essentially crabwalks around the corner and down the straightaway. This is detriminetal to straightline speed but significantly increases downforce. So when it comes to the larger 2 mile and higher tracks, the positive skew can be a detriment because of the excess drag down the straightaways.

NASCAR Rear Skew

Courtesy of

The simplest way of changing your rear end skew is by just clicking the rear toe in either direction. However that doesn't get you to the absolute limit of failing tech. At most tracks even fractions of a degree of rear skew will add up to lots of speed especially later in the run.

By manipulating your trackbars, you can create more skew than just clicking the rear toe.

Let me show you some examples

In this image above, we have our rear toes at +5 and -5 for our upcoming race at Lucas Oil Speedway. If we click either toe one more click, we end up failing tech because the toe goes past its limit to +7 and -7. How can we combat this?

By changing our rear trackbars to manipulate the toe further.

In this image above, our rear toes are at +6 and -6, right where we want them. We achieved this by increasing the Right Rear Trackbar from 6.250 to 7.250. By increasing the RR Trackbar you increase positive rear skew. You can increase that RR Trackbar until the toe exceeds its limit, and at that point just go one click back so it passes tech. This extra one degree of rear skew in the center of the corner is a huge gain in speed.

iRacing Setups
iRacing Setups

Analyzing Different Stints

With the default tools iRacing provides, it's near impossible to see what how what you're doing is effecting the setup. With the Stint Analyzer tool, you are able to analyze your and opponents stints during practice or in the race! I use this everytime I build a setup to make sure I am making positive adjustments. While testing, I disable dynamic weather and sky to keep my laps and results consistent. I'll provide the link to Stint Analyzer below.

Stint Analyzer preview
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