Dynamically adjusts vehicle tyre grip on wet ground based on real wheel slip, rain and ground wetness. The effect activates only when tyres actually slip and mainly during slow work speeds, keeping road driving stable even in heavy rain. The slider in game settings controls the strength of the wet-grip effect. Lower values preserve more traction. Higher values increase wheel slip on wet ground. Takes tyre width and dual wheels into account and works automatically on all wheeled vehicles.