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New Super Duty, which gear?

Husqy510

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I'm getting ready to order a new F-250 crew cab short bed 4x4 powerstroke. It will get a leveling kit and 35s, and will be pulling a small travel trailer a few times a year. My main concern is fuel economy as it will get driven 280mi to the river regularly. Which gears do you recommend 355 or 331? Any other options you wish you had got, or regret getting?
 

OldSchoolBoats

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I'm getting ready to order a new F-250 crew cab short bed 4x4 powerstroke. It will get a leveling kit and 35s, and will be pulling a small travel trailer a few times a year. My main concern is fuel economy as it will get driven 280mi to the river regularly. Which gears do you recommend 355 or 331? Any other options you wish you had got, or regret getting?

Not sure if this is even relevant, because we are comparing a 6 speed versus 10 speed transmission, but for what it is worth, I am running 355's on my 2019 250 with leveling kit and 35's. My average fuel economy going to and from the river is about 15 MPG. I also have a 2WD valance on the front which I have been TOLD will decrease fuel economy.
 

LargeOrangeFont

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3.55s.

My friend with a '21, short bed crew 4X4 6.7, 3.55s and 10 speed on 35s with the horrible snowplow valence is getting around 18 MPG at 80 going to the river.

You could deal with 3.31s though, especially if you were never towing real heavy. The 3.55s will feel peppier with the 35s, and feel like a good match.
 
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idk

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I have a 21 f250 and was concerned about the 3.31 gears but I can tell you it isn't a problem, the 10 speed trans makes it work. I lost 2 mpg leveling it with 35" and trimming the snow plow, I get 19 mpg not towing to the river just the truck doing 80mph and 15.5mpg towing the boat to the river and 14mpg towing my 24' enclosed tailer with bikes and RZR and there is no problem with power. The 21 destroys my buddys 17 for fuel milage he gets 13mpg going to the river empty. I haven't even tried it with the econo mode I'm just starting to play with that now.
 

LargeOrangeFont

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I have a 21 f250 and was concerned about the 3.31 gears but I can tell you it isn't a problem, the 10 speed trans makes it work. I lost 2 mpg leveling it with 35" and trimming the snow plow, I get 19 mpg not towing to the river just the truck doing 80mph and 15.5mpg towing the boat to the river and 14mpg towing my 24' enclosed tailer with bikes and RZR and there is no problem with power. The 21 destroys my buddys 17 for fuel milage he gets 13mpg going to the river empty. I haven't even tried it with the econo mode I'm just starting to play with that now.

Good info here.
 

Husqy510

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Great info guys, thanks. I'm buying a powerstroke because that's the truck I want, simple as that. I'm sure I could get by with an F150, but that's not what I want. I may end up with a slightly larger trailer at some point, but probably no bigger than a 30' fifth wheel.

If the 331s will work for my application and net 10-15% better fuel economy than I'd prefer that route. If it's going to feel sluggish or be hard on the trans than I'll get the 355s, but something tells me it's not going to feel sluggish with nearly 1000ftlbs of torque.

Thanks again for the input.
 

hallett21

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Are the 10 speeds basically a 6 plus 4 gears or do you get better low end gears as well?


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Flying_Lavey

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BTW, those giant valances are actually to get better mileage. I don't really think they make that much noticeable difference, but it is to direct air around the truck instead of under it where it causes turbulence and other issues that reduce efficiency.
 

hallett21

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I believe its 7 + 3?

Sorry I meant are you getting 4 more gears on top of what a 6 speed is? Or do you get better 1,2 gears and then really tall 9,10s? If that makes sense.


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Flying_Lavey

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Sorry I meant are you getting 4 more gears on top of what a 6 speed is? Or do you get better 1,2 gears and then really tall 9,10s? If that makes sense.


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I don't know what the individual ratios are, but I thought I remember reading 7th is 1:1 so below that is under driven and above is overdrive gears. I could be wrong though.
 

HitIt

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For those looking to compare ratios, here are the old and new trans along w/several rear end ratios and the final drive ratio calculated.

ratios.png


Also, F mileage. You are already in "impractical" territory. Might as well really go for it, especially since you are going to lift it. I went the impractical route on my truck order, too. I dont regret it. And I dont think you will see a 10% difference.

edit: above is for the 10R80 which has the same ratios as the 10R140

 
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LargeOrangeFont

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Are the 10 speeds basically a 6 plus 4 gears or do you get better low end gears as well?


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Same (relative) gear spread, wirh a shorter first and taller top gear, and a closer ratio spread. Gears 8, 9, 10 are overdrive. 10th gear is taller than the 6 speed, 9th is pretty close to the 6 gear in the 6 speed. That is most of the reason for better mileage. The ability to keep the engine right at its torque peak across several gears is the key.
 

MonkeyButt70

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I have a 2021 F350 4X4 DRW 6.7 10 speed, 4.10 rear gear with stock tires. I average about 16-17mpg. At 85mph my RPM is about 2100.
 

HitIt

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One thing that you will notice on these 10 speeds is that first and reverse is looooow. 1st in 4-lo is almost laughable.
 

evantwheeler

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I'm getting ready to order a new F-250 crew cab short bed 4x4 powerstroke. My main concern is fuel economy as it will get driven 280mi to the river regularly

Lets be honest, you truly cant care about fuel economy if youre spending $80k+ on a truck that gets used to drive 300miles to go on vacation regularly.
 

LargeOrangeFont

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Lets be honest, you truly cant care about fuel economy if youre spending $80k+ on a truck that gets used to drive 300miles to go on vacation regularly.

When a $50k truck will do the same job and get better economy.

But he was up front and said that is what he wants... nothing wrong with that, but frugality is not part of the equation.
 

Bowtiepower00

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If fuel economy is your main concern, get the 3.31s, keep it stock height, and don’t get 35s. The leveling kit and 35s are going to cost 1-3 mpg. If you are definitely going to go bigger on the tires, I’d get the 3.55, you have plenty of gears, but you will spend more time in the higher ones with the deeper gears, plus, the extra gear will be nice when towing.

I’m in the camp of get the deepest gear you can. That being said, both of my Rams have been 3.42 trucks with 35’s, and even with a 6 speed I have plenty of power. Running under 2k RPM at 80+ is nice too.
 

ArizonaKevin

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If the plan is for bigger tires, get the 3.55. After the bigger tires go on your final drive will be closer to the 3.31.

Agree with some of the other sentiments that a modern half ton may do the job you are looking for better than a 3/4 ton. I also understand that buying a car isn't always the most rational enterprise and there's nothing wrong with getting what you want because you want it. We all work hard and should be able to get exactly what we want
 

CLdrinker

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Get the 3.55’s
The $15 of better fuel mileage is nothing for a baller buying a $80,000 truck.

If saving money is a concern. No need for a leveling kit and tires. Leave it stock and get 3:31’s.

But let’s be honest. You are buying a bad ass truck and you want it to look bad ass hence why you are leveling it and adding tires.

Saving a couple bucks on fuel mileage ain’t shit.
 

idk

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Great info guys, thanks. I'm buying a powerstroke because that's the truck I want, simple as that. I'm sure I could get by with an F150, but that's not what I want. I may end up with a slightly larger trailer at some point, but probably no bigger than a 30' fifth wheel.

If the 331s will work for my application and net 10-15% better fuel economy than I'd prefer that route. If it's going to feel sluggish or be hard on the trans than I'll get the 355s, but something tells me it's not going to feel sluggish with nearly 1000ftlbs of torque.

Thanks again for the input.
I was skeptical at first the 3.31 but now I'm very impressed my buddy with the 17 is impressed too, its got a shit ton of power take the traction Control off and its on the speed limiter right now !!
 
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idk

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3.31-3.55 is a negligible difference, its not like your looking for a 100th of sec. or a half mile an hour in et. If I Were buying another one off the floor with 3.31s I'd do it and not look back. If your going to put 37" tires on it I'd consider the 3.55. I have the Lariat package and the wheels and tires that it had were right at 34" so going 35" no biggie. Go drive one with 3.31, I live in the SCV if your near me you can take mine for a spin if you want. I will say I use a lot more def than my buddys 17 truck .
 

boatpi

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So 35’s will kill the mpg, period. And 331
Are best but with 35”, go with 3.55. My stock 2017 had 3.31 and it was perfect.
 

Dettom

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If Trump were still in office and diesel was back down to 1.89 a gal, you wouldn’t see threads like this.
 

HCP3

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So 35’s will kill the mpg, period. And 331
Are best but with 35”, go with 3.55. My stock 2017 had 3.31 and it was perfect.

35" tires aren't very big these days. Depending on the package, 4X4 F-250's come stock with 285/75R18. 34.8". Any smaller and it will look goofy with a leveling kit.

I vote 331.
 
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JD D05

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Get the truck you want! F-150's are for golfers and country wives to go to Costco. I had a long bed on 35's that got 21 unloaded but it was deleted. I haven't driven both enough to give you honest feedback. I had a 6 speed and spent all my time manually shifting the truck with heavier weight. If you can hold 2300 RPM's that ideal towing grads.
 

spectra3279

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My dodge has 3.73 gears and is a six speed. My tires are one size up from stock. I wish it had another gear. Pulls like a freight train but at 70 I'm about 2100 rpm.

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Husqy510

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Thanks again for the info. So far I haven't talked to a single person that owns a truck with 331s that regrets the decision, and the 355s requires an additional upgrade I'm not interested in. So 331s is the route I think I'm going to go.

I'm getting the blackout version, so I don't plan on changing the wheels. Most likely just a leveling kit with a little more aggressive tire.
 

Husqy510

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My dodge has 3.73 gears and is a six speed. My tires are one size up from stock. I wish it had another gear. Pulls like a freight train but at 70 I'm about 2100 rpm.

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I had an older cummins with a 5 speed and it had the same issue. 75 was about as fast as it wanted to cruise.
 

boatpi

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My 2017 had 18 inch on it I forgot the diameter of the tires but remember when I was getting the truck the fleet manager told me stick with the 331 because of the transmission internal gear ratios.

that wasn’t even a 10 speed it turned out to be the best advice ever received in years. It’s newer engine has crazy torque.
 

boatnam2

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I got what your looking to get but with 3.55's, tows my bicycle like its not even in the truck. Hopefully someday I can get something to really see how it tows. One thing for sure, truck is a beast but will make your hemi flare up on the small bumpy stuff.
 

Bpracing1127

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18 here on 37’s with the 3.55 and I get 14.7 at 85 mph 1900 rpm
 

McKay

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Mine came with 4.30 and I was a bit worried I would not like it. However after pulling 8000 miles this summer I love it. I am a bit heavier than most with the boat trailer at around 16-17k. Tow at 75-80 most everywhere and get 9mpg.
 

idk

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Thanks again for the info. So far I haven't talked to a single person that owns a truck with 331s that regrets the decision, and the 355s requires an additional upgrade I'm not interested in. So 331s is the route I think I'm going to go.

I'm getting the blackout version, so I don't plan on changing the wheels. Most likely just a leveling kit with a little more aggressive tire.
Talk to Brandon Lake mead boater on here he will take care of you on tires and lift, great guy https://www.riverdavesplace.com/forums/threads/lake-mead-boater-does-it-again.235636/
 

DLow

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I drive a stock ‘20 with .331s every day at work, and I drive it pretty hard. I can’t see putting 35s on it would have any negative effect on it towing with how low 1st and 2nd gears are. These things are also making crap loads of torque. It will pull whatever you throw at it as long as you stay under max weight ratings.
 

Riverryder

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I’m not even a Ford guy but I just read this whole thread.
Boats
cars
Trucks
Anythin with a motor is fascinating to read about and the passion that people have for this shit.
 

Good Stuff

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35" tires aren't very big these days. Depending on the package, 4X4 F-250's come stock with 285/75R18. 34.8". Any smaller and it will look goofy with a leveling kit.

I vote 331.

I was just going to type this out. Even the 20” wheels come with 34.5” tires.
 

Bowtiepower00

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It’s the width- not the height- that kills MPG. If you’re throwing on some 285’s, the hit will be minimal. Some true 35’s or 325’s, and you’re going to see a decrease- and the deeper gear is worth it. These trucks fit 37s nowadays- but most can’t fit a 37 spare under the bed if that’s a concern. Carli is supposed to be offering a cradle that fits a 37” spare, for about 2k.
 

sczagurs

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Thanks again for the info. So far I haven't talked to a single person that owns a truck with 331s that regrets the decision, and the 355s requires an additional upgrade I'm not interested in. So 331s is the route I think I'm going to go.

I'm getting the blackout version, so I don't plan on changing the wheels. Most likely just a leveling kit with a little more aggressive tire.

Add the 3.55. You will not regret it especially with 35” tires.
 

HCP3

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Thanks again for the info. So far I haven't talked to a single person that owns a truck with 331s that regrets the decision, and the 355s requires an additional upgrade I'm not interested in. So 331s is the route I think I'm going to go.

I'm getting the blackout version, so I don't plan on changing the wheels. Most likely just a leveling kit with a little more aggressive tire.

I think it is a great choice. 1050 TQ and a ten-speed trans... You will be fine with 331's down low, and have a better cruising speed/rpm.
 
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