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Who Cried when Old Yeller picked the WRONG gear ratio?

spars332

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*Raises Hand* I've searched but, have not found a definitive answer for a "Noob" on going offroad. I apologize if I missed a thread. I've never driven offroad, I've been a passenger but, I never asked about tires or rearend axle ratios. So for an offroad setup for a daily driver (No extreme rock climbing) what rearend and tire size?
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FirstOnRaceDay

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*Raises Hand* I've searched but, have not found a definitive answer for a "Noob" on going offroad. I apologize if I missed a thread. I've never driven offroad, I've been a passenger but, I never asked about tires or rearend axle ratios. So for an offroad setup for a daily driver (No extreme rock climbing) what rearend and tire size?
defiantly go mid range.

one of the two middle range Rear ends. If your just going trail hopping or dune running. No crawling

I’d go. 4.27 rear end with 265/70r17 or 285/70r17

I imagine that’s going to be the most common combo. Still very capable yet comfortable and easy to live with daily
 
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spars332

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defiantly go mid range.

one of the two middle range Rear ends. If your just going trail hopping or dune running. No crawling

I’d go. 4.27 rear end with 265/70r17 or 285/70r17

I imagine that’s going to be the most common combo. Still very capable yet comfortable and easy to live with daily
Thank you for the response! I appreciate the advice greatly!!
 

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defiantly go mid range.

one of the two middle range Rear ends. If your just going trail hopping or dune running. No crawling

I’d go. 4.27 rear end with 265/70r17 or 285/70r17

I imagine that’s going to be the most common combo. Still very capable yet comfortable and easy to live with daily
Spot on IMHO...
 

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*Raises Hand* I've searched but, have not found a definitive answer for a "Noob" on going offroad. I apologize if I missed a thread. I've never driven offroad, I've been a passenger but, I never asked about tires or rearend axle ratios. So for an offroad setup for a daily driver (No extreme rock climbing) what rearend and tire size?
Figure out what tire size you want to run and go from there. Switching tires is cheap and easy.....compared to regearing two differentials. $$$$$$$

Looking at the rumored 37" capability????
There's a WILD difference between the 32" tire and the rumoured 37's. Even when I compared 33's to 35's, you'd be better off with the right gear....there was no good compromise.
Think you might tow a small camper/trailer/pair of jet skis/boat ??? Favor the lower gears.

Gotta keep that in mind. 37's, or any tire for that matter, that is geared incorrectly will make you hate the damn thing. It will either be a dog at low speed or scream at hiway speeds.
If the calculators are inbetween gears.... For drivability, I'd go with a touch lower gear,
Find the manufacturers specs on the tire, especially the revolutions per mile, and enter that in a reputable gearing calculator.
A good goal is 2000 engine rpm @ 70mph in top gear.
Best/coolest gearing calcultor I have found:
http://www.grimmjeeper.com/gears.html
Have fun!
 
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spars332

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Figure out what tire size you want to run and go from there. Switching tires is cheap and easy.....compared to regearing two differentials. $$$$$$$

Looking at the rumored 37" capability????
There's a WILD difference between the 32" tire and the rumoured 37's. Even when I compared 33's to 35's, you'd be better off with the right gear....there was no good compromise.
Think you might tow a small camper/trailer/pair of jet skis/boat ??? Favor the lower gears.

Gotta keep that in mind. 37's, or any tire for that matter, that is geared incorrectly will make you hate the damn thing. It will either be a dog at low speed or scream at hiway speeds.
If the calculators are inbetween gears.... For drivability, I'd go with a touch lower gear,
Find the manufacturers specs on the tire, especially the revolutions per mile, and enter that in a reputable gearing calculator.
A good goal is 2000 engine rpm @ 70mph in top gear.
Best/coolest gearing calcultor I have found:
http://www.grimmjeeper.com/gears.html
Have fun!
Awesome thank you Hoosier!
 

The Pope

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What's the "currently rumored" OD ratio (Auto/Manual)? 0.80 to 1 ?????
 

FirstOnRaceDay

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What's the "currently rumored" OD ratio (Auto/Manual)? 0.80 to 1 ?????
0.6357:1 for the auto
Around 0.7:1 for the manual

on the 34.4” tires with 4.7 rear end and automatic trans
that’s only 2042RPM AT 70mph
 

Cooknn

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...on the 34.4” tires with 4.7 rear end and automatic trans
that’s only 2042RPM AT 70mph
I plan on that combination of tire and gear. Good choice?
 

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Agree with the detailed info above. Unlike some who want to put 40’s on it, I am running 33.3’s 295/70-17 on a 4 door JK now with 4.10 gears, and miss the 285’s I was running before because they behaved better.

With the Bronco, bigger tires may be the easier way to gain ground clearance. But there is a daily driver trade off there for extra capability that you don’t need most places off road.
 

Beachin 74

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You are going to have folks come on here and say "the 10 speed transmission is a game changer".:rolleyes:

There is no substitute for a low (high numerically) set of axle gears when you are running large tires.
 

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Food for thought when you're trying to figure out which Tire Size and Gear Ratio you want.....

A former Co-Worker who drag raced always spoke about "True Gear". That's the calculation of the Tire's O.D. & Gear Ratio to calculate the "True Gear" that the driveline sees.

With that in mind and my rough calculations.....
32" w/4.27 (TG 2.779)
34.4 w/4.46 (TG 2.695)
37 w/4.7 (TG 2.621)

As all of these combinations True Gear are "relatively" close to each other, they "should" accelerated and perform (within Butt Dyno) basically the same as.....

So, if someone can verify my calculations, I'd appreciate it, as I could be totally off.
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