If you're referring to what gear to use when driving a manual transmission automobile that will vary depending on the vehicle. Me personally, based on my car, if I'm doing 30 mph I'm typically in 2nd gear.
If it is a 4 speed you would normally be in 3rd. If it is a 5 speed you would be in 4th. A 6 speed you would be in 5th.
2nd or 3rd gears
When going uphill on a bike, it is recommended to use a lower gear to make pedaling easier. This will help you maintain a steady pace and conserve energy.
Typically, you should use gears 3 or 4 for speeds in the range of 15 to 25 mph on flat terrain. These gears provide a good balance between pedal effort and speed. Adjust based on your comfort and the terrain.
most of the time it saves gas but you should use low gear when towing or going down a steep hill
When going uphill on a bicycle, it is recommended to use a lower gear to make pedaling easier and more efficient. This will help you maintain a steady pace and conserve energy while climbing.
you should use high gear when cruising and you should use low when you are towing a trailer or if you are going through mud
Second gear should handle the 15 - 25 mph range nicely, but if the engine seems to be racing a little, third gear probably would be better. It depends upon whether there is an up- or down- slope in the road, and the weight of the car.
One level below the highest
Use a low gear. Which gear you should use depends on how steep a hill you are talking about and also how far down does the hill go. and are you using a standard or automatic transmission. Common sense should tell you to use a lower gear if the vehicle accelarates to much.
not overdrive... it depends how fast ur going
To properly use the gear shift on a bike, you should first understand how the gears work. Lower gears are for easier pedaling on inclines or starting from a stop, while higher gears are for faster speeds on flat terrain. To shift gears, use the gear shift levers on the handlebars to move the chain onto a different gear. Shift to a lower gear when going uphill or starting, and shift to a higher gear when riding on flat ground or going downhill. Make sure to pedal lightly while shifting to avoid damaging the gears.
Only if you're going so fast that you are beyond the torque peak in 5th gear (over 150 MPH, I'm guessing). The reason to use it at lower speeds is for better fuel economy, less engine wear, and (especially) less noise. It's not so easy to hear the radio in 5th gear on the highway.