The maximum number of forward gears in a production-car manual transmission is seven. Seven-speed manuals have been fitted to road cars such as the Chevrolet Corvette C7 and Porsche 911.
The Corvette’s Tremec TR-6070, introduced for the 2014 model year, added a seventh overdrive ratio to the familiar six-speed design. Its extra gear was intended mainly to lower engine speed, improve fuel economy and reduce emissions during cruising—not to make acceleration dramatically quicker.
A seven-speed manual is unusual because each added ratio increases mechanical complexity and makes the shift pattern harder to package. Most manuals use five or six forward gears, while modern automatics commonly offer eight, nine or ten because electronic controls can select them without requiring the driver to coordinate every shift.
Reverse is not counted as a forward gear. That distinction is why a seven-speed manual is described as having seven forward speeds even though its complete transmission also includes reverse.