Your math is... math. Equal speed in same gear = higher rpm for shorter final drive = less fuel economy.
Real world : we drive at different speeds all the time, unless you like to *cruise it* at the exact same speed all of the time because, well, it's very important to you, has special meaning or something...
Real world driving with a 9 speed not hitting top speed(edit > gear) kinda makes the math less... interesting, and brings physics to the forefront.
Looking at members' mpg numbers on these forums, it's hard to tell which is tall and which is short gearing, to me anyway. Statisitics are math, kinda. More data needed for accuracy of course, but it's fun to do quick observations.
If my KL is in 8th at, say, 56mph and a taller geared KL is in 7th, then... which is getting better mileage ? If the shorter geared KL can keep 8th with a slight head wind at 76mph and the taller geared can't... which one gets home with more gas left in the tank ? But yeah, if both need to go 80 and both stay in 8th gear, then the taller guy wins because that's the math.
My avatar is the Elder Predator
(goes well with my forum status and overall temper
2015 North (Canada) - V6 - AD1
Cold, Tow, 8.4A, 9 speakers with sub
Last edited by Mark_; 08-02-2015 at 11:32 AM.
Reason: edited speed to gear somewhere in there..