The next-generation NASCAR Cup car – to be introduced for the 2021 season – will use wheels with single securing nuts, replacing the five-nut rims that have been part of the sport for many decades. According to NASCAR officials the move to a single-nut rim has been made necessary by a planned change to 18-inch aluminium wheels from the current 15-inch steel items. The single-nut wheels, which have been commissioned from German manufacturer BBS, were revealed in the latest test of the Next-Gen car at Auto Club Speedway, Fontana on 2nd-3rd March. NASCAR senior VP of innovation and racing development John Probst said that with the wheel rim size moving to 18in to more closely relate to current production cars, it was necessary to ensure the wheels were suited to a racing environment. “Once you get to an 18-inch aluminium wheel, the next step for us is to make sure that… under racing conditions it will accept the durability that we need to finish races and then also finish multiple races – to do that, the single nut was our only option,” Probst said. The plans have already caused controversy among many fans of America’s top motorsport category, but Probst argues that the major visua...