Your game framerate drops from 60 to 30 fps? Bored from experience stuttering and inconsistent framerate despite of have solid 60 frames?
Perhaps you don't know this is a Milestone game and the Milestone engineers aren't the best, they are "dragging" the same issues since the start of the past console gen; stuttering and bad vsync (also much other problems).

Happily this have quick an easy solution* in PC version:

-Disable V-sync in the games launcher

-Go to your Graphics card Control Panel and under 3D Setup, select Control the 3D setup, and switch to Program configuration; find and select in the list Sebastien Loeb Rally Evo (slrx64.exe).

-Go to the down in the list and select V-Sync and set to Adaptable**, also set Triple Buffer to on.

-Apply and close, launch the game and check.

*Tested in Nvidia GTX 760 and 970, AMD probably works too.

**If your system don't have enough power for run the game at 60 frames probably this don't make a great difference, you can try to set the V-Sync to adaptable (medium frequency) for 30 fps sweet and solid.

Note/ My system is in spanish, perhaps in english or any other language the name of the option may differ slightly.

This is my first guide, I hope help people to have a better game experience, thanks for reading and enjoy game.