does upshifting drop RPMs not because its harder to spin the wheel, but rather the opposite? And gears in general

Question

For example, if you shift to 2nd to 1st, does the rpm jump not because the engine load has decreased and it can spin faster, but rather because it has to work harder than it would in higher gears?

In: Engineering

Answer 1

The work the engine needs to do is the same. The question is what speed (as in RPM) makes it easier for the engine to do the work. Higher revs have byproducts like more friction, more heat, etc.

The other interesting thing to realize is that, all else being equal, having more weight in the car will need to use more fuel to turn the engine at any given RPM.