I apologize if posted before, but I disappear for weeks at a time and have no memory.
Someone correct my understanding:
A higher real axle ratio means more drive shaft RPMs per turn of the axle, which allows the engine to get up into the higher HP ranges faster, which means better acceleration. That same axle ratio, because it results in higher RPM at a given speed, means less gas mileage on the highway and a lower top end speed, since you hit the redline at a lower speed. Is this correct?
Now let's add tire size: A larger tire pushes the car further each time the axle turns, because of the larger circumference. Thus, a bigger tire turning the axle one time puts more pressure on the engine than a smaller tire doing the same thing, since it must move the car a few inches further.
Assuming the above assumptions are correct, and they may be wrong, it seems to me that a larger tire would counteract the benefits of a high rear axle ratio, in that we slap on that 3.73, 4.11 etc. to take pressure off the engine and allow for faster RPM gain, then put on large tires which add pressure to the engine and reverse the benefit of the high rear axle ratio by slowing the climb through the RPM band.
I must be wrong, but I just can't grasp the math. Help!