Hydroplaning: the Role Tires Play(Lea en español)
Hydroplaning happens when one or more tires is lifted from the road by a wedge of water that gets trapped in front of and under a tire as the vehicle drives through water. Hydroplaning most frequently occurs during heavy rainstorms when water creates puddles on the highway or expressway. In addition to the accompanying splash and scaring the heck out of the driver, hydroplaning typically causes the steering wheel to jerk and the vehicle to abruptly pull towards the puddle.
The speed at which a tire hydroplanes is a function of water depth, vehicle speed, vehicle weight, tire width, tread depth and tread design. It depends on how much water has to be removed, how much weight is pressing down on the tires and how efficient the tread design is at evacuating water. While deeper water, higher speeds, lighter vehicles, wider tires, less tread depth and less efficient tread designs will cause tires to hydroplane at lower speeds; all tires will be forced to hydroplane at some speed.
As a rule, tread design affects hydroplaning resistance at high speeds and in deep water. Tread compound affects wet traction at lower speeds or in shallow water.
Directional tread designs (sometimes called Unidirectional tread designs) are frequently used on tires intended to better resist hydroplaning. Their multiple tread grooves are aligned in a repeating "V" shape to increase the tire's ability to channel water from between the tire's footprint and the road. Somewhat like the vanes of a water pump continually pushing water in one direction through the engine, the grooves of a directional tire are designed to push water in one direction through the tire (forward on an angle to the sides). Directional tread designs are especially helpful in increasing hydroplaning resistance when relatively wide Plus Two, Plus Three or Plus Four tire and wheel applications result in fitting a much wider tire to a vehicle than its Original Equipment size.