Spikes

Spikes Schwalbe spikes generally have a core made of extremely hardwearing tungsten carbide. The base is fully galvanized steel.
For more grip the spikes of the Ice Spiker Pro have an even stronger core made of Wolfram Carbide, one of the hardest known materials. For reasons of weight reduction spike bases and cladding are of light weight aluminum.

Tires need to be run-in for 25 miles / 40 km on hard-top road to ensure spikes are permanently fixed. Avoid rapid acceleration and braking during this period.

Incidentally: In Germany bicycle tires with spikes are permitted on roads, in contrast to car tires!