Originally Posted by
jimmuller
And when/why did it become "compulsory" to mount them with the label at the valve stem? A directional tread at least requires the label be on a particular side (and on the right only if the manufacturer made it that way). But I see no reason for the position other than style and perhaps convenience of reading the pressure when pumping up.
for racing tires, the thread is a design thing - they could be bald, but bald tires don't sell for some reason. (it's not only me who is saying that, but also a Conti engineer..). So "directional treads" are pretty dispensable, too.
(The "aquaplaning" effect encountered on cars is due to the patch -contact area between tire and road- being way bigger and way, way wider than on a bicycle, and the speed being potentially higher. A bicycle tire's patch is very narrow, it will just cut through the water, unless you reach speeds of 150+)
About the "label at valve stem" thing i don't know; possibly came with clinchers becoming more popular. Bike mechanics love those tiny details, which have no effect on the way the bike actually rides, but show it has been built with the utmost attention to detail.