Quote:
Originally Posted by racerc2000
is taller always better? I was thinking shorter would infact be better with my setup if I wanted less sidewall which I dont. the 5 spd auto is over geared as it is. its under 2k rpm @60 and cant go on more then a 3% grade before downshifting. a taller tire would make this worse?
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In town, sometimes yes, it is possible that reducing tire diameter will help. I've simulated running my car through the UDDS and HWFET and found that with some trans options a shorter than stock tire will return better results on the UDDS than the stock tires will.
over 1/2 of my commute is ~35mph. At 35mph, my car will go down to 3rd with even the slightest load. Reducing the tire size mitigates this.
Conversely, swapping to a manual trans that is geared longer overall would allow me to get respectable mileage around town in 4th
and have good economy in 5th on the highway.
If I ever do the high mileage build I want to do, it will involve the longest geared SOHC transmission, and 23" tires to drop the car by .5", and springs to go down as far as I can total. My rpm in OD would still be approx 10% lower than now.