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Old 11-22-2009, 07:42 PM   #40 (permalink)
bestclimb
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Join Date: Oct 2009
Location: South Central AK
Posts: 933

escort - '99 ford escort sport
90 day: 42.38 mpg (US)

scoobaru - '02 Subaru Forester s
90 day: 28.65 mpg (US)
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Quote:
Originally Posted by bondvagabond View Post
I think the stock spare tire racks are pretty wimpy. I wouldn't want to tar up the sheetmetal in the tailgate if that's all that was supporting the boattail structure.

Anyone got good data on the pro's and con's of increasing there final drive ratio by putting on bigger tires? you'd have more rotating weight, but fewer rpm/mile=less gas.

I'm wondering about mildly bigger tires to lower cruise rpms. just what I could get away with without a lift. Someone was mentioned on here that the reason the samurias had the same mpg's even after the swap to fuel injection was that they lowered top gear. I don't mind gutless if it gives me the sweet mpgs
If you go with taller tires but not wider I think you could see some slight gains. I am making the assumption that the aero is so bad on a samurai that the slight increase in drag from taller tires will be lost in the noise so to speak. I know the guys modding the samurai like the shorter 5th but that is for much larger tires, where they are trying to get some torque back.

I currently have 225 75 15s with out any lift. I have no trouble with the tire touching. If you could find a 225 70 or 65 you may see some improvement. If the tires are wider than stock I would bet you would loose a little mileage. This is assuming that the increase in tire drag is lost in the rest of the drag of the rig and that the engine is still in an effecient rpm range for your speed. I know these things love to rev and need to be wound up a bit to make head way.
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