New Tesla Gearbox Ups Range to 244 Miles, Hits Zero to 60 Time of 4.0 Seconds Tesla Motors is finally rolling out its long-awaited single-speed transmission for the all-electric Tesla Roadster, which will pare down durability issues while upping torque and range. The new gearbox, made by transmission whiz kids Borg Warner, lets the Roadster hit its promised zero to 60 time of 4.0 seconds while upping travel distance to 244 miles per charge. If you're one of the 27 people who already own a Roadster, Tesla will be offering a free retrofit come next month. Now that the gearbox is all figured out, the company expects to start producing 10 new Roadsters every week, ramping up to 40 per week by early 2009. [NextAutos via Jalopnik]