thanks for the reply. besides testing my own in a series of coast down tests. is there a source with more tire info? say specific rr # as opposed to just low rr tire
I figured new rubber will always be worse then worn rubber when comparing RR. considering the car only has 13k miles ide hope the new/worn ratio wouldnt be as bad.
but. I dont think the SC 18s (225/55-18 goodyear LS-2)or the base model 16s (215/70-16 Wrangler HPs) were focused towards fuel economy.
the wheels have been purchased but tires have not yet. so I can still make a better choice in both width of tire and diameter.
I know in many cases my move to light weight 19s would be a bad move.
I was trying for the lightest pairing of wheels and tires for the original selected size. but maybe I should look at it from a different angle.
wheels. save 12lb each. would 4lb be a negligible gain/loss if said tire has more/less RR (4lb+ heavier tire but lower RR)(4lb+ lighter but higher RR)
is there a specific ratio or scale/graph for when certain characteristics makes a gain in FE negligible.
ie: taking heavy aero type wheels and heavy extreme low RR tires
compared to feather weight non aero wheels and normal RR tires?
if Im going off on a tangent im sorry.I have an engineers mentality and a thirst for knowledge.
Quote:
Originally Posted by ProDarwin
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.
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my auto will act the exact same. it is a 3 spd auto with 2 overdrives.
Gear Ratios: 1st: 2.786, 2nd: 1.614, 3rd: 1.082, 4th: .773, 5th: .566, Reverse: 2.000, Final Drive: 4.500
luckily I do have the option of a 6spd manual. (oem 5 spd manual uses a 6spd manual case so its an easy mod) that may be an option but costly.
but really. unless I chop off the roof it will never be on any top fe lists.