A lot of speed shops lower the final drive ratio to increase torque. Is there a part one can by and install that will increase the final drive ratio, which would decrease torque, but also decrease engine speed and improve fuel economy?The 2005 Civic hatchback was only sold in an Si model and this model was geared for speed rather than fuel economy.A lot of speed shops lower the final drive ratio of cars to increase torque. Generally speaking, this trades speed for fuel economy.I'd like to go the other direction: is there a part I can buy and have installed that will increase the final drive ratio. This would decrease torque, but also decrease engine speed and improve fuel economy?A couple of people answered this question by pointing out that larger tires are a way to go to increase the drive ratio, and they are bang on, but on this particular model, the tires already pretty much fill the wheel wells.