Technologue

Elon Musk’s original Tesla Roadster used a two-speed transmission. It proved problematic, so he dropped the extra ratio and still delivered cars and SUVs capable of both brutal acceleration and license-endangering top speeds. So who needs multiple gears? Gearing an electric motor to deliver strong launch torque and then spinning it fast enough for autobahn speeds presents serious cooling challenges and reduces efficiency. Hence today’s fastest EVs—like the Porsche Taycan, the Pininfarina Battista, and Rimac C Two—use a two-speed transmission. Why a two-speed transmission when 10-speeds are readily available? Electric motors have a vastly broader “sweet spot” of efficient torque delivery than combustion engines, so they don’t need frequent shifting to remain efficient. A low range with roughly double the ratio of the high range generally suffices for passenger vehicles. Adding…