Why do you have to increase rpm's to shift more smoothly? Isn't the next gear providing lower revs?

Question

For example if shifting from 2nd to 3rd, someone said they increase revs to match the next gear when shifting.

Answer 1

This will explain it in detail.
http://en.wikipedia.org/wiki/Synchromesh#Synchronized_transmission

Answer 2

It has to do with gear ratios. When the car is stopped, you need more torque to get moving. This is done with more RPM (revs) and slow wheel speed. Then as you get moving you shift to a different ratio which requires less torque since the car is already moving. Each gear ratio is the difference of the engine RPM to the wheels turning. Lower gears have more RPM with less wheel rotation for power, and higher gears have less RPM for many wheel rotations for speed.

Engines build power at higher RPMs. So this requires the driver to shift to different ratios to maintain power so the engine doesn't get stalled, or over rev'd.

Hope that makes sense.

Answer 3

You don't, you should switch up when you believe the next gear can handle it, over reving a gear is just wasting petrol if your not using it to instantly gain speed. All modern cars have syncromeshs so all the gears are spinning already, theres no benefit for the gearbox or for smoothness to over rev a gear before changing

Answer 4

They may have been talking about down shifting and not up shifting.