湿牵引性是讨论得最多的轮胎特性之一。轮胎在湿路面上的摩擦因数（μ）可以通过制动试验进行测量，它与胎面胶配方、胎面花纹设计、轮胎特性、界面条件（温度、路面温度、水深）、轮胎载承负荷、速度、路面和打滑值等有关。μ可用下列不同作用的因数和来表示：μ＝μａｄ... Wet traction is one of the most discussed features of the tire. The friction coefficient (μ) of a tire on a wet road surface can be measured by a brake test in combination with a tread compound, tread design, tire characteristics, interface conditions (temperature, pavement temperature, water depth), tire load, Speed, pavement and skid value and so on. μ can be expressed in terms of the sum of the following different contributions: μ = μad