Transportation and Vehicle Safety: Speed selector & speeds

Question
Hi Michael,

Do you know the speed ranges for the different gears in automatic and manual transmission? Let's say, when the speed selector is in the "D" position what's the range of speeds in MPH for that gear, etc

Thank you in advance,

Richard

Answer
Hi Richard,

There are general speed ranges for the gears in a manual transmission.  First, understand that each car is a unique machine - a sports car will shift differently than a box truck, because of differences in mass, size and gear ratios.  But the general rule of thumb is as follows:

First gear is used primarily for starting the vehicle into motion (breaking the inertia of being at rest).  By 5-10 MPH, you should be shifting into second gear.  By 15-20 MPH, you should be looking for third gear.  By 25-30 MPH, you should be considering fourth gear.  Fifth and sixth gears are common on some cars, absent on others, but would largely be used for periods of sustained high-speed driving (freeways).

That said, occasionally you break these rules.  You may shift down to a lower gear despite your speed to increase power uphill or decrease speed downhill, or to give yourself more power to pass efficiently.

An automatic transmission uses "Drive" (the "D" gear).  It uses this for everything from stop to highway speed, allowing the car to select gears by itself as needed for the conditions.  Most automatics also have the ability to manually select the relevant gear, should you need to downshift for a hill.

Hope this helps!