6.7 cummins with 35's mpg

regularcab2500 · Oct 20, 2014

Arctic-Rodz said:
MPG is very important, i still cant belive some here bashing others with that concern...

As I am looking into getting a new 2500 CTD im also looking to stay in the 35" tire range. But im going to stick to All Terrains. Interested in seeing how it affects MPG and power since the only option is 3.42 gears.

What would be the ideal gear ratio for those 35" tires? The original tire on some Tradesman models ive seen have 275/70R18 tires = 33.2" height. So from there to 35" isnt a hugh increase in overall height, but i imagine its the weight and resistance from the more aggressive tire you decide to run that hurts MPG the most?

maybe wait till 2015 for your purchase as they are adding 3.73s and 4.10s to the option list as well...the point of it is that you cant be so concerned with mpg if you really want to lift the truck! that will kill your mpg especially in the city but like i stated previously many lifted diesel drivers have told me gearing down helps significantly..wait till you can order 4.10s for your truck its the best way to go imo..

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Arctic-Rodz · Oct 20, 2014

True that, thanks...
So you think 4.10 for a 35" tire would be ideal?

The 35" tire i will go with is the ProComp Radial Xtreme A/T. Not too aggressive. I like that it looks like a simple military truck tire

regularcab2500 · Oct 20, 2014

well let me put it this way..i told my dads mechanic who drives a lifted cummins that i wanted 4.56s and he said if i dont go to 35s that my rear end would howl a bit on the highway since i only have stock 33s so id say 4.10s would be plenty of gear for you unless you plan on being at max capacity often

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Arctic-Rodz · Oct 20, 2014

No, it will probably be doing towing duty 40% of its time. Maybe a bit less but the fact that what I'll be towing is at or just about 1-2k lbs more than what my 1500 is rated at id rather just get a 2500 Cummins.

My dealer has 2 Tradesman trucks with 6" lifts and 37" mud terrains. I think I should go drive them and see how they do. I'm sure a lot worse than the same truck with just a level and 35" all terrains.

I'm sure they'll try to sell it to me anyway lol

regularcab2500 · Oct 20, 2014

definitely check into the lifts intalled as well as off road suspensions often reduce the trucks factory capabilities in heavy dutys

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ramguy11 · Oct 26, 2014

Just wanted to chime back in here.

I will clear up one thing before I post my long"ER term results on my MPG.

I can afford anything I am extremely comfortable financially. Does not mean I waste money. If you do then im sorry but you are just a ******* and you belong in office somewhere.

Here are my numbers I am seeing here now. The trucks have been on for 5 tanks of fuel now.
My hand calc average is around 16mpg in town but on the highway I am not fairing too bad at all.
Hand calc is 18mpg~ most of my highway driving is east on I-12 in Louisiana. From the time I merge on to the time I get off Im at 70-80mph.(majority around 75, it's what I set my cruise too)

I have a screenshot below of my EVIC, I have my cruise set at 75mph. Yea it is reading a bit high but like I said my average is hand calc around 18mpg. This is a flat stretch.

ImageUploadedByTapatalk1414364228.908196.jpg

ImageUploadedByTapatalk1414364242.875055.jpg

hounddog · Oct 27, 2014

NWRQC said:
Depending on the OE tire size that came with your truck and how close to a true 33" tall tire, your tires are about 1.5" - 2.5" taller than stock so your speedo is off. Between the aggressive tread and the speedo being inaccurate your mpg number will be off.

Yup.

Use this to help you figure out what you're probably actually doing.

OnlineConversion.com - Bigger Tires

Arctic-Rodz · Oct 29, 2014

18MPG is not bad, what tires are you running there RAMGUY11?

I recently test drove a 2014 RAM 2500 CTD with a 4" lift and 35" Cooper STT M/T tires. Looked good but it rode pretty crappy.

I have yet to drive a stock 2014 to compare it to. Considering my purchase to be a 2014 but only a Leveling kit and 33x12.5R20
Not sure if its going to look too small in the wheel well after its leveled though. Going for a flush look, not too much tire sticking out.

loveracing1988 · Oct 30, 2014

regularcab2500 said:
well let me put it this way..i told my dads mechanic who drives a lifted cummins that i wanted 4.56s and he said if i dont go to 35s that my rear end would howl a bit on the highway since i only have stock 33s so id say 4.10s would be plenty of gear for you unless you plan on being at max capacity often

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The rear end won't howl, your engine might sing but that will be it. Power wagons came with 4.56 gears and 33's until 2014, your mileage will suffer but the off the line torque will be awsome.

regularcab2500 · Oct 30, 2014

loveracing1988 said:
The rear end won't howl, your engine might sing but that will be it. Power wagons came with 4.56 gears and 33's until 2014, your mileage will suffer but the off the line torque will be awsome.

That's good but I'm not using him anyway..you can tell he charges too much because his truck is damn ridiculous

Arctic-Rodz · Oct 30, 2014

loveracing1988 said:
The rear end won't howl, your engine might sing but that will be it. Power wagons came with 4.56 gears and 33's until 2014, your mileage will suffer but the off the line torque will be awsome.

The 2014 Tradesman have 275/70R18 tires which is a 33" height. But the only gear ratio is 3.42, going to a 35" tire will make the truck feel like its gone down to a 3.21 ratio maybe?

loveracing1988 · Oct 30, 2014

Arctic-Rodz said:
The 2014 Tradesman have 275/70R18 tires which is a 33" height. But the only gear ratio is 3.42, going to a 35" tire will make the truck feel like its gone down to a 3.21 ratio maybe?

I was referring to the 6.4 in that case. With the Cummins with 35's 3.73's would be nice. I think 4.10's would be overkill unless you don't care about highway mileage.

hounddog · Oct 30, 2014

regularcab2500 said:
i didnt mean to offend anyone either..its totally reasonable to want better mpgs out of your big ass truck its just not totally realistic to expect numbers like mid 20s for mpgs in a 7500lb truck made for hauling heavy loads..i hate people on here ******* that their lifted truck gets bad mpgs..of course it does haha!!! lifts, big tires and rims are only hurting your mpgs

but many ive talked to said gearing down helps tremendously

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I hate to tell you, having had a '14 2500 CTD with the 3.42 gearing, it is NOT a truck meant for heavy hauling.

When I told my dad I was thinking of getting rid of the 2500 and replacing it with a 3500/Aisin/3.73 gears his response was, "You can have a truck that gets great mileage, or, you can have a truck which is great at pulling. You can't have both."

I have learned that $118,000 lesson the hard way having bought two $55,000+ trucks in 6 months.

So please feel free to let RAM know they nearly lost another 7 time RAM buyer to GM because of their **** gearing package.

Arctic-Rodz · Oct 30, 2014

hounddog said:
I hate to tell you, having had a '14 2500 CTD with the 3.42 gearing, it is NOT a truck meant for heavy hauling.

When I told my dad I was thinking of getting rid of the 2500 and replacing it with a 3500/Aisin/3.73 gears his response was, "You can have a truck that gets great mileage, or, you can have a truck which is great at pulling. You can't have both."

I have learned that $118,000 lesson the hard way having bought two $55,000+ trucks in 6 months.

So please feel free to let RAM know they nearly lost another 7 time RAM buyer to GM because of their **** gearing package.

That bad? .3 gear ratio makes that much difference?

What are you pulling?

RoloTahmasee · Nov 1, 2014

hounddog said:
I hate to tell you, having had a '14 2500 CTD with the 3.42 gearing, it is NOT a truck meant for heavy hauling.

When I told my dad I was thinking of getting rid of the 2500 and replacing it with a 3500/Aisin/3.73 gears his response was, "You can have a truck that gets great mileage, or, you can have a truck which is great at pulling. You can't have both."

I have learned that $118,000 lesson the hard way having bought two $55,000+ trucks in 6 months.

So please feel free to let RAM know they nearly lost another 7 time RAM buyer to GM because of their **** gearing package.

Or you could just go get a gear change. Put in whatever gear you want, the options are limitless.....

loveracing1988 · Nov 1, 2014

RoloTahmasee said:
Or you could just go get a gear change. Put in whatever gear you want, the options are limitless.....

When you are paying $50000 for a truck you shouldn't have to out $2000 more into it for a gear change.

NWRQC · Nov 1, 2014

loveracing1988 said:
When you are paying $50000 for a truck you shouldn't have to out $2000 more into it for a gear change.

Well when you pick the wrong gear ratio from the get go, it's cheaper than selling the truck and buying a new one. :waytogo:

loveracing1988 · Nov 1, 2014

NWRQC said:
Well when you pick the wrong gear ratio from the get go, it's cheaper than selling the truck and buying a new one.

The only gear ratio available for the 2500 cummins is a 3.42, it isn't like it is the buyers fault ram doesnt give them a choice.

Stangshcky12 · Nov 1, 2014

loveracing1988 said:
When you are paying $50000 for a truck you shouldn't have to out $2000 more into it for a gear change.

You shouldnt but I feel like itd be cheaper to swap gears then to eat the depreciation
Sounds like someone would've been better off with a DRW truck from the start

ramguy11 · Nov 2, 2014

Arctic-Rodz said:
18MPG is not bad, what tires are you running there RAMGUY11?

I recently test drove a 2014 RAM 2500 CTD with a 4" lift and 35" Cooper STT M/T tires. Looked good but it rode pretty crappy.

I have yet to drive a stock 2014 to compare it to. Considering my purchase to be a 2014 but only a Leveling kit and 33x12.5R20
Not sure if its going to look too small in the wheel well after its leveled though. Going for a flush look, not too much tire sticking out.

I am on 305/55r20 Mickey Thompson atz p3's. I love them. Wearing great so far too.

Idk what all this talk is about **** gearing and can't haul a load!! You guys need to get off these forums because you are just spewing ********.

I pull big loads for work all the dang time my load first thing in the morning will be a 30ft gooseneck with dual 8k axels. The load itself will be a 11k lb column and some inconel manways. Total haul should be around 14k trailer and cargo. It pulls it just fine. The truck has 750ft lbs of torque and 385hp. It pulls like a damn mule.
I don't have many pics. I will try to get one tomorrow of this load. Here is a lighter load. Grossed around 9k with trailer and 90.
This is a 34" 90deg elbow with an expansion joint. It's 1/2".
My truck has 22k on the odo and has never disappointed.

ImageUploadedByTapatalk1414989102.604155.jpg

6.7 cummins with 35's mpg

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