Also, things are not ever equal like wheel diameter and size.

The "road bike" we're talking about has a larger diameter and thinner tires. that means less effort to keep the wheel rolling by way of bigger tires, less drag both friction-wise and aerodynamically from the tire width.

Also, i'm not riding a bike without tires. Road tires and made to roll faster, by way of compound used and lack of knobby tread. Mountainbike tires are made to be more grippy offroad, with "stickier" compounds and knobs.

I would've just said troll right at first, but your post seems thought out, even if incorrectly.