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Which tire ? (bear in mind "granny"will help crawl ratio)

  • 31's Net gear ratio of 3.15 ish

    Votes: 4 23.5%
  • 32's Net gear ratio of 3:00 ish

    Votes: 2 11.8%
  • 33's Net gear ratio of 2:75 ish

    Votes: 10 58.8%
  • 30's Net gear ratio of 3:25 ish

    Votes: 1 5.9%
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Discussion Starter · #1 ·
Starting point:
87 Bronco EFI 5.0 4spd (T-18?) 3.54 gears 235/75/15 tires, 17 mpg if I keep it at or below 60 mph.

Desired effect:
Basic off road ability, some rocks, some trails, leetle bit more clearance.

Suggestions?

(keeping in mind, I don't want to spend over 1,000 including tires; and drive it 65 miles a day so wanna keep or expand the mileage)

My thoughts were better intake, higher flowing exhaust and 32's.
 

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You could run 33 10.50's if you're worried about gas mileage. Intake and exhaust, as well as basic tune up stuff will help. I don't know what kind of mileage you'd get but you might get into the mid teens, probably not 17 though.
 

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Discussion Starter · #3 ·
Am getting 17 now, want to stay close to that.
 

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Added weight is going to cut mileage, as will increased friction from a wider tire, and drag from the tire. Don't get me wrong, it might only be 1 mpg but it will be less then what you're getting right now. That's actually really good mileage in a big bronco. My toyota only gets like 15 mpg... I guess it's that whole rotating mass thing. :rotfl::rotfl::rotfl:
 

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I had almost the exact same bronco. I only got about 15mpg in it, and I was running 31x11.5 all terrains.

Your running EFI, and I gaurantee Ford spent more on researching the characteristics of that stock intake manifold than edelbrock or any other aftermarket intake would spend. Plus the whole point of the intake/exhaust mods is to flow more air, and kinda lean out the mixture. Thus improving mileage. Well with EFI the computer will read the new lean condition and dump in more fuel, so fuel consumption stays the same.

17mpg is pretty dang good. I don't think anything you do will really net you enough of a return to make it a good investment. Just crunch the numbers. 500bucks for a new exhaust will buy 225 gallons of gas at today's prices. Thats 3825 miles at your stated mpg.

Now lets say you buy that exhaust and gain 1mpg (I think that's unlikely, EFI and all that). You can now go 4050 miles on that same 225 gallons of gas. So in that situation it could be wrth the money.

:rotfl: :rotfl: Now we all know that you have never kept a 4x4 for longer than one month:rotfl: :rotfl: So even if you got the work done, and improved the mileage, then you would still be out the cost of the exhaust.

Now that I am done with my long winded dissertation, here's my thoughts. Run skinny/small highway tires. Then when it's time to play throw on some old 33" mudders and hit the trail.
 

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Discussion Starter · #6 ·
Easy on the one month thing, average is like 3 months......
At 75 driving it like I would drtive it if I didn't care about mpg, I got 14.6, and was in the "second set of barrels".

By upgrading intake, I just meant, higher flow to the manifold, although I have read negative about the manifold that I have, Mustang mani's are supposed to be a better mousetrap.

I thought that by lengthening the ratio with say 32's, and gaining a leetle leg there, I could offset the added drag of the bigger heavier tire (althought leaning towards 17's and alloys, lighter weight package, and I work at a new car store so take offs are somewhat plentiful) by increasing intake flow, ram air, and higher exhaust flow, headers, dualed and flowmasters......

And create say a rig that did 16 - 18 reliably, and was an okay trail rig.
 

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Just some info on tires for you. BFG AT's in 235/75 15's weigh 35lbs, 31's weigh 41lbs, 33 10.50 15's weigh 47lbs, 33 12.50 15's weigh 52lbs. That's according to tirerack.com I think that 33 10.50's on aluminum rims would be the ticket for both worlds.
 

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:drool:I envy you. :flipoff:I have a 85 fullsize bronco with the 300 six. I run 33x12.50's with 3:55's and get 10-11 on the highway and 8 in town.:lame::lame: With the stock tires I was only getting 12 on the highway and 10 in town. :lame:So I really envy you. If I was getting 15 right now I would be HAAAPPYYYY!!!!!!!!:rotfl::rotfl:

Go with the 33's, I like the extra hight and ground clearence. Plus you don't loose that much, you wouldn't even notice it.:thumb:
 

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Discussion Starter · #9 ·
gonna go with really used 245/75/16 for now, wrapped around newer Ddoge 2wd Chromies, then thinking either 285/75/16, or 255/85/16.

We have an Idaho power truck in the shop now with the 255's in a radial RVT, and it is about what I want.

Then 2.5" in the front to level, then a shackle flip in the back, and done.
 

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Discussion Starter · #10 · (Edited)
Side not on the mpg, 25 ish gallon tank, (25.779 to fill it the first time) and sitting on 600 + miles with 15 gallons added to the first tank.
 

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Discussion Starter · #11 ·
Now I just picked up a 78 3/4 ton, FE Block, unsure on the c.i.d. at this point, and 60's front and back, high pinion 60 in the front.
(3.54 gears)

Do I gut it to make the Bronc tight as Fawk?

Do I wheel it, and pass Trigger onto the wife?

SHould I try to find a club cab body for it (that would be hot!) or a dead Bronc and build a rock rig?





Too many questions
 

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take your keyboard out to the drive way and drive either one of them over the keyboard a few times then bring it back inside and let us know how it worked out.
 

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Try put on some 33x9.50-15's on you get the height but not as much drag as the wide 33's that are out there!!

Might drop a mile or two with that.
 
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