NGK Motorcycle spark plug R2525-10

The spark plugs used for racing must withstand particularly high voltages. The engine speeds reached during a race often exceed 15,000 rpm. The temperature, pressure, and vibrations in the combustion chamber are so significant that conventional ground electrodes could break or melt.

That’s why racing spark plugs are often equipped with ground electrodes specially designed for competition, with the most extreme form featuring a ring ground electrode. The spark "jumps" from the central electrode to the ring ground electrode.