Difference Between Overdrive and Drive
When we talk about power transmission in automobiles then we come across these two terms, drive and overdrive. In simple terms the top gear is the overdrive while other gears are drive. These options are available in your cars whether it has manual gears or automatic transmission.
Drive consumes more fuel but gives more power and this is why it is better to drive your car in overdrive when you are driving at high speed so that the engine of the car can run at low rpm and consume less fuel. If your car has 5 gears then 5th gear is the overdrive and rest 4 gears are drive.
You should drive more at overdrive except when you want to slow down or when your car needs more power like in case of driving uphill. Though overdrive does not allow you to reach the maximum speed of your car, it is fuel efficient way of driving. You need to use drive if you want to reach the maximum speed of your car.
In case of drive, the wheels and engine move with the same speed with a ratio of 1:1 while in overdrive this ratio remains 0.66:1. This ratio of overdrive results in high speed with fuel efficiency, lesser noise and lower torque. But overdrive must not be used or driving uphill or while pulling loads.