The present invention includes tire treads (10) and a method for forming tire treads (10) having a sipe (18) with a length extending between opposing terminal ends of the sipe and having a height and a thickness which is variable across the length and height of the sipe. The thickness of the sipe (18) includes a sipe portion arranged between the opposing terminal ends defining the sipe length and having a thick portion extending at least partially around a perimeter of a thin portion. The thin portion is substantially 0.2 millimeters or less thick and forms at least 40% of the surface area along each of the opposing sides of the sipe, the opposing sides being arranged on opposing sides of the sipe thickness.