What does changing gears in a car do mechincally speaking?

Does it changed how many pistons are used? What happens in the engine when you change gears and why do you go faster after changing to a high gear?What does changing gears in a car do mechincally speaking?
all that changes in the engine is load and rpm, the transmission is physically changing the gear ratio that it is using to multiply power to the next device (transfer case or differential. by changing to a higher gear you change to a closer to 1:1 ratio (under drive) or an overdrive ideally ( output is turning faster than the input.)What does changing gears in a car do mechincally speaking?
ye-yeah, dats rite!
At lower gears, the engine will transfer power to wheels, but the engine will run at very high revolutions per minute (rpm) to do so. This is actually a good thing when the car is starting from a dead stop. There is enough power going to the wheels to get the car moving, and the engine is turning fast enough to keep it moving.



As the car goes faster, the engine can no longer go any faster, but it is still only transferring a small amount of momentum to the car. A gear change allows the car's engine to slow down, but transfer more momentum from the engine turning to the car's wheels. This is accomplished by changing the gear ratio in the tranmission. When you move to a higher gear, the gears on the engine side get more teeth, and the gears on the drive shaft get fewer teeth. This allows the engine to transfer more momentum to the wheels. This process continues as you move to higher gears.



Each time the gear ratio changes to a higher gear, the car must be moving faster. The higher gears are able to transfer momentum, that is revolutions of the engine, efficiently to the wheels, but they are not able to transfer torque as efficiently. Torque is the ability of the engine to overcome the resistance o the drive shaft to turning. Torque is highest at the lower gears.



Hope this helps.