BMW is convinced its current transmission policy of eight-speed automatics, seven-speed dual-clutches and six-speed manuals is the perfect combination, according to its small and midsize cars boss, Klaus Frolich.

Speaking to Auto Express at the launch of the new X4 and 4 Series Gran Coupe – both of which offer an eight-speed ‘Sport Auto’ paddleshifter option – Frolich expressed scepticism at the gearbox policies of rivals Jaguar Land Rover, Mercedes and Cadillac, all of whom are working on transmissions offering nine or more forward speeds.

“We ran some tests” explained Frolich. “The [efficiency] difference between an automatic with six speeds and eight speeds is seven or eight per cent, which is a good result. But the benefit for nine speeds [instead of eight] is almost zero per cent. Plus, it adds weight, complexity and cost, and with turbocharged engines you have a good spread of torque, so [drivers] do not want to have the gearbox constantly changing its mind.”

Quizzed over the policy to equip BMW’s M Division cars with a seven-speed dual-clutch gearbox (known as M-DCT), Frolich said: “Seven gears is not optimum, it is a compromise. As in a manual gearbox, in a twin-clutch you must arrange all the gears in a line, so for weight and packaging reasons we are limited to seven speeds. But our new turbo M cars have so much torque this is no problem. DCT remains right for M cars because we can’t make a torque-convertor that would be durable up to 8000rpm.”