what tire size and gears

[harder93]

i daily drive my bronco just wondering what gearing and tire size is the most streetable and gets the best mileage i have a 289 3 speed and what other mods will boost mileage

 

[TN1776]

Lots of variables to consider. Start with this tool to figure out your engine speed for any tire size/gear combination you can dream up: http://www.grimmjeeper.com/gears.html

Obviously with gears too high you'll sacrifice low-end grunt so it's a balancing act. Good luck.

 

[Broncobowsher]

Shorter skinny street tread pattern. 235/75R15 to about a 30x9.50R15 will do your best to keep rolling resistance to a minimum. Leave the stock 3.50 gears in there.

Taller, wider, more aggressive tires eat gas mileage.

 

[harder93]

i have 32s x 10.5s and 3.50 gearing now

 

[blubuckaroo]

You've asked a pretty open ended question. It really all depends on your planned usage, elevation, and such. I was pretty happy with my 3.50s and 31" tires until I went traveling into the higher elevations in the Sierra Nevada mountains. The car would have been fine as a flat-lander but was disappointing in the mountains. I went to 4.11s and that was like magic.

 

[crankman]

33 tires with 4.11 gears

 

[harder93]

with the 3 speed it redlines down the highway and sucks down the gas pretty fast its miserly a flat lander i plan to buy a Jeep cj5 after this build for my Wheeler

 

[BronCowie]

with the 3 speed it redlines down the highway and sucks down the gas pretty fast its miserly a flat lander i plan to buy a Jeep cj5 after this build for my Wheeler

enjoy your cj harder............

 

[broncnaz]

Do you know what your current axle gearing is? That 289 is probably far from redlining. it will happily cruise all day long at 3000 RPM. A little engine tuning may help the gas situation a bit

 

[harder93]

the carb i have is an old carter its about to be switched out for something new havent quite decided what one yet. redlining may have been exagerating a bit its more like wrapping out at about 70. as far as i know its just the stock gearing it has a fresh rebuild on it now and am still working out the bugs and fixing the rocker arm studs that keep pulling out bending and snapping.

and i just cant bring myself to beat on a bronco. mine is straight and rust free and im restoring it with all the upgrades. i dont feel as bad beatin a cj lots more of them were made and i will most likely buy a pre wheeled pile to start from

 

[Broncobowsher]

If you are pulling studs, then it sounds like you have an engine that isn't stock. That makes for a whole different can of worms. Add in an aftermarket carb on that modified engine that still has bugs in it. No telling what you will need to try and squeeze anything that resembles double digit gas mileage out of it.

 

[harder93]

no its not stock but its not heavily modified either forged pistons small cam shot peened crank hydrolic lifters edelbrock performer 289 intake nothing too fancy im not sure what my mileage is at the moment but id like to get the best mileage i can hwy. i drive mostely in town 45 mph 5 miles to work i dont care what the mileage is there but once i get into hunting season and im driving over the passes and across the state thats where i need the mileage

 

[phred]

Ok going just 5 miles will barely get the engine, transmission and rear up to operating temp. 45 mph I assume with scattered stop lights. You'll be lucky to get 10mpg. I have hot 302 33x12.50, c4 and 4.11 gears and get 16 on the highway if I stay at or below 65 mph. In town I get 8mpg. The engines are gonna eat some much gas no matter what sitting and idleing. When I drove the truck daily on stock tires, stock gearing and engine I managed 10-11 intown. Just the reality of owning a vehicle that was built when gas was .25 cents per gallon. The little 289 gonna like the rpms to make power so expect it to spin.

 

[dube]

I have 411s with 33" 12.5x15 but might think about 35" any down fall to that?