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3.73, 4.27 & 4.46 ratio on-road?

Mountain Bronco

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I am having a hard time deciding on the potential final gear ratio for primarly on-road use. This decision will guide trim level.

My build will be a daily driver and country road cruizer. I live in a hilly mid-atlantic region with all four seasons.

What would be your recommendation for best on-road ratio? 2.7 V6, auto, tire size would be stock 32. (largest would potentially option of 33 in the furture.) I am not even opposed to A/T p-rated tires for daily use and second set of M/T.

I have ran all of the gear ratio calculators. With the 10 speed auto trans, there are so many gears, the rpm's almost get self corrected.

My primary goal is fun to drive, acceleration with comfort. MPG is not really a concern. I currently get 12 mpg

Thanks for the help!
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dgorsett

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Both transmissions have multiple overdrive gears, so 4.27, 4.46 or even 4.70's will be fine on the highway. I think 3.73's might be too high (low numerically). One of my reservations about a Base Automatic.
 

JT1

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Start with your tire size and work backwards. If 33's are as big as you'll ever use, 4.46s or 4.27s on an auto/2.7 will be fine. Look at your normal highway speed and see where you land at 70/75/80 with the 2 or 3 ratios. At 80, there probably isn't 150rpm difference between 4.46 and 4.27 in 10th
 

xusarmy

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I am having a hard time deciding on the potential final gear ratio for primarly on-road use. This decision will guide trim level.

My build will be a daily driver and country road cruizer. I live in a hilly mid-atlantic region with all four seasons.

What would be your recommendation for best on-road ratio? 2.7 V6, auto, tire size would be stock 32. (largest would potentially option of 33 in the furture.) I am not even opposed to A/T p-rated tires for daily use and second set of M/T.

I have ran all of the gear ratio calculators. With the 10 speed auto trans, there are so many gears, the rpm's almost get self corrected.

My primary goal is fun to drive, acceleration with comfort. MPG is not really a concern. I currently get 12 mpg

Thanks for the help!
My setup sounds about the same as yours, and not even sure if I would put on 33's. I dont live in a hilly area, heck at this point, I dont drive a whole lot ;-) I like to go fast from time to time (110mph), but not often, just enough to keep it trained. Would probably get into some off roading, but nothing big. Im definitely going 2.7, Auto.

Thanks for your assistance,
 

da_jokker

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I wonder what the MPG difference will be with a Non-Sasquatched BL with the higher gears (lower Number) vs one with and the 4.7 and larger wheels?
 

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Incognito

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4.7 is the sweet spot for 33" tires.
4.47 is best with the 30" Base tires.

Everything else will be slower off the line.


And while a 4x4 is not for drag racing, performance gears work less in city traffic and therefore, ironically, give better stop and go MPG than "CAFE highway mileage master" gears.
 

da_jokker

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4.7 is the sweet spot for 33" tires.
4.47 is best with the 30" Base tires.

Everything else will be slower off the line.


And while a 4x4 is not for drag racing, performance gears work less in city traffic and therefore, ironically, give better stop and go MPG than "CAFE highway mileage master" gears.

So is 4.7 not low enough to be the sweet spot for 35's
 

Incognito

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So is 4.7 not low enough to be the sweet spot for 35's
Technically, 5.38-5.68 would be best for the high revving Ford engines and 35-37" tires.

Too bad the only axles that will take gears that deep and live a long life are, ironically, the classic Ford 9" axles.
You're looking at +$10,000 swap to do that.


The Bronco's OD gears are deep enough and the engines are powerful enough in very high RPMs, to get away with using OD to drive and direct (7M) 1st OD(10A) pass.

Older Brand X vehicles have either low RPM big block power that needs shallow gears for highway cruising. Or deep OD gears in a weak engine.

The Bronco is the first to have the best of both in one package.
Hopefully, the aftermarket will pick up and a 9" swap will get cheaper.
 

jaruss01

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In short if you plan on getting OBX 2.7 and upgrading to 33s, you’ll want to pay the 795 for higher gearing....plus the cost of 33 tires is another step towards why the badlands pricing works. My badlands build is less than my OBX total costs which is why I’m switching over.
 

Lab00Rat

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Calculator I found has the gear ratios similar to 5th for the manual and 9th for the automatic transmission.

All speeds kept similar at 70mph.

Ford Bronco 3.73, 4.27 & 4.46 ratio on-road? 1603648228445

Ford Bronco 3.73, 4.27 & 4.46 ratio on-road? 1603648241136


Ford Bronco 3.73, 4.27 & 4.46 ratio on-road? 1603648253827

Ford Bronco 3.73, 4.27 & 4.46 ratio on-road? 1603648265234


Feel free to dive deep, and let us know what you find.
https://spicerparts.com/calculators/engine-rpm-calculator

4.46-33s and 4.7-35s is closer to normal for me in RPM and driving conditions at 70mph.
 
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VoltageDrop

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Go test drive an F150. I don't think there will be a bad gear/tire combo with the 2.7. 3.73 will be fine. I'm wondering if the 2 door sasquatch will pull a wheelie! o_O
 

JT1

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Technically, 5.38-5.68 would be best for the high revving Ford engines and 35-37" tires.

Too bad the only axles that will take gears that deep and live a long life are, ironically, the classic Ford 9" axles.
You're looking at +$10,000 swap to do that.


The Bronco's OD gears are deep enough and the engines are powerful enough in very high RPMs, to get away with using OD to drive and direct (7M) 1st OD(10A) pass.

Older Brand X vehicles have either low RPM big block power that needs shallow gears for highway cruising. Or deep OD gears in a weak engine.

The Bronco is the first to have the best of both in one package.
Hopefully, the aftermarket will pick up and a 9" swap will get cheaper.
I wouldn't consider either of the bronco motors as "high revving". Both are in boost early in the band and run out of breath at the top of the tach.
 

Incognito

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I wouldn't consider either of the bronco motors as "high revving". Both are in boost early in the band and run out of breath at the top of the tach.
Classic truck V8s are passing peak at 3000rpm.
The 2.3L , is just getting started at 3K.

The torque curve on both the 2.3l and 2.7l are very flat compared to classic V8s too.
 

JT1

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Classic truck V8s are passing peak at 3000rpm.
The 2.3L , is just getting started at 3K.

The torque curve on both the 2.3l and 2.7l are very flat compared to classic V8s too.
I would consider the early 5.0 (pushrod, not the coyote) and the 2.3 power delivery fairly similar. The 2.3 has the edge in raw numbers, and there isn't much lag. Both are out of breath about 5500 rpm.
 

Incognito

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I would consider the early 5.0 (pushrod, not the coyote) and the 2.3 power delivery fairly similar. The 2.3 has the edge in raw numbers, and there isn't much lag. Both are out of breath about 5500 rpm.
Which is about 3500-4000 rpm higher than where a 460 in a f150 on 35"s will comfortably cruise on the highway.

Which was my point.
The new engines require us to rethink rear end gearing towards deeper sets.
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