This patch adds a game option that lets you choose a linear multiplier to decide how long mud should be visible on wheels.
When driving off the field, I thought the game cleaned up the muddy tires too soon, even though I've always enjoyed the way they appear. Depending on how you configure it, this tweak keeps the tires dirty for a longer period of time.
Mud length multiplier is an option that can be found under the 'General Settings' tab. The multiplier for how long mud should stay on the wheels after leaving a field is determined by this parameter. The mud lasts longer when there are more of them. The default value of the mod is 5.0. The default setting of the game is 1.0.
Under the hood, this mod divides the multiple given in the options by the off-field multiple for cleaning wheels, which is a negative number.

Thanks to RichOPick