Racing spark plugs: to resist loads especially hard
Racing spark plugs must be able to resist especially hard loads because races often exceed 15,000 rpm.
Temperature, pressure, vibrations and currents in the combustion chamber are so large that a conventional ground electrode could break or burn out.
For this reason, racing spark plugs are designed, for example, with a ground electrode in ring-shaped. Instead of jumping, the spark slips from the Center electrode to the ground.