Continental Grand Prix 4000 S II Tire Folding Bead
Claimed to be stronger than steel, this offers additional resistance to penetration from road debris while being ultralight. Combined with Continental's Black Chili rubber compound, super-tiny carbon black particles incorporated into the rubber formula, the GP4000 S II is versatile enough for race wheels or training wheels.
The tiny size of Black Chili particles allows them to mold to variable road surfaces more readily. It gives the tire greater ability to conform to imperfections in the road surface for excellent grip in demanding situations—such as high speed cornering—while also reducing rolling resistance. Since the Black Chili particles are so small, more particles fit into the contact patch of the tire, reducing tire wear and increasing tire longevity.