[RedDevil]

Originally Posted by TexasCotton

You have stated several issues and now am lost and concern
Your terms quoted "skinny, tall, and large" just confuse and jade my perspective and not my understanding

Clearly going from 15 inch to a large rim 17 inch only reduce mpg and there is a thread already that is active to that accounts for that very experience

Ah, you mean this thread.
That's all about changing the rims but not the outer diameter of the tires, as to not offset the speedo and gearing.
To have bigger rims with the same thread diameter you have to decrease the sidewall height, which means those lower sidewalls will bend (relatively) deeper and cause more friction.
Those tires are not taller, they just have a bigger hole on the middle.
(gotta coin #bigholetires to demean them GTI boys' rubber strips on halved oil barrels)

This thread is about tires with a bigger outer diameter. So the rims have to grow in diameter too, or the sidewalls would get too high.
A bigger size (circumference, largeness, tallness) means also a larger contact area with the ground, so the tire can be made narrower (skinny) to compensate.