The things you learn . . .

From Tricks of the Trade:

Consumers generally won't buy a bicycle with completely smooth or treadless tires, even though the tread pattern serves no purpose and tires would be cheaper to make (and therefore buy) without it.

People think bicycle tires should have tread because car tires have tread. But car tires have tread for a reason. In wet conditions water has to be given a way to flow from under the tire's contact patch, so the rubber can remain in contact with pavement and prevent hydroplaning. A car tire is much larger than that of a bicycle tire, thought, and the water has much further to travel.

Physics dictates that the pressure forcing water from below the car's tire is equal to the pressure of inflation, typically 30-40 psi. With a bicycle road tire, however, inflation pressure is typically 80-120 psi. In other words, in comparison to car tires, bicycle tires have much smaller contact patches and much higher pressure -- the two physical parameters of concern in hydroplaning.

The speed required to hydroplane on a bicycle has been calculated in the region of 90-100 mph.

Added: 4/07/2005 05:35:00 PM
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