Iracing: Best app.ini for Force Feedback Latency Fix

The objective is to minimize the Signal Smoothing delay while ensuring the physics thread (running at 360Hz) communicates effectively with your wheelbase’s driver.

File Path & Access

File Path: %USERPROFILE%\Documents\iRacing\app.ini

Step-by-Step Instructions:

1. Press Win + R on your keyboard, paste the path above, and press Enter.
2. Locate the file named app.ini. (Crucial: Create a backup named app_backup.ini before editing).
3. Right-click the file and open it with Notepad or Notepad++.
4. Find the [Force Feedback] section.
5. Modify the variables as shown in the configuration block below.
6. Save the file and restart iRacing.

Optimized “Direct-Link” Configuration Block

[Force Feedback]
allowDirectInputEffects=1
displayLinearInNm=1
FFBAlwaysActive=1
FFBSmoothing=0
FFBType=0
recenterMaxTorque=0.000000
steeringDirectInputServos=1
steeringFFBSmoothing=0

Parameter Details & Technical Purpose

Parameter	Recommended Value	Technical Purpose
steeringFFBSmoothing	0	The Latency Fix. Removes the internal software filter, providing raw, unfiltered data to your wheelbase.
steeringDirectInputServos	1	Optimized for Direct Drive systems (Fanatec, Simucube, Moza). Bypasses legacy HID layers.
FFBAlwaysActive	1	Keeps the FFB thread awake even when the car is stationary, preventing “wake-up” lag during initial movement.
displayLinearInNm	1	Allows you to set your FFB based on actual Torque ($N \cdot m$), ensuring a 1:1 linear physics response.
allowDirectInputEffects	1	Enables low-level driver access for specialized “vibration” effects like ABS or curb strikes.

Best Practices for 2026 Sim-Racing Input Stability

To fully eliminate input lag in iRacing, follow these additional GameEngineer.net technical steps:

• Wheelbase Software Filter: Since we set steeringFFBSmoothing to 0 in the INI, your wheel might feel “grainy.” Use your wheelbase’s native software (like Simucube TrueDrive or Fanatec Control Panel) to add a tiny amount of Hardware Interpolation. Hardware-level smoothing is significantly faster than iRacing’s software-level smoothing.
• CPU Affinity and Threading: iRacing’s physics engine is extremely sensitive to single-thread performance. Use Process Lasso to ensure iRacingSim64DX11.exe is running on your fastest cores and that “Core Parking” is disabled.
• USB Polling Rate: Ensure your wheelbase is plugged into a USB 3.0/3.1 port directly on the motherboard. Avoid USB hubs, as they introduce Packet Jitter, which directly correlates to micro-fluctuations in FFB strength.
• The 360Hz Physics Hook: In the in-game settings, always check the “Use Linear Mode” box if you are using a Direct Drive wheel. This matches the displayLinearInNm=1 tweak and prevents the signal from clipping at high torque loads.