Crew Cab 1500's MPG with 35's

[ram1500rsm]

Curious to see what you guys are getting modded, I know mine is not breaking any hypermilling records, but i thought it was kind of nice to know the truck is getting me the same MPG my Jeep Wrangler Unlimited was giving me, and i think is good considering the Jeep had the V6 Pentastar Engine with 4.56's and 35's, while the Truck has the Hemi 5.7L with 3.92's, 35's, and it's at least 1000lbs heavier.

So far i'm getting low 15's, 70% highway, 30% city, lots of traffic between Orange county and LA back and forth , i guess i can expect low to mid 16's hwy only. This is driving at 70mph on the fwy whenever possible to maintain that speed, usually 50 out miles out of 140 miles daily, rest is slow bump and go traffic, gotta love Los Angeles fwys at peak hours... , This week i'm slowing down to 68mph and see if there is in improvement, Truck is a 2014 crew cab, 4x4, 5.7L, 65RFE trans, leveled in the front, tires are Falken AT3W 315/70/17 E rated, 73lbs each, Wheels are Raceline Clutch 17x9, 26lbs each, for a total of 99lbs in each corner, soon extra 99lbs in the bed, as i'll be mounting a spare back there.

 

[WilliamS]

Mine a a tad taller than 35's as most 35's are in the 34.75 range or some are even 34.5. I have 295/65-20 which measure out to 35.75 inches tall inflated on the truck. I went from 21 mpg on my daily commute in my Hemi 4x4 Crew Bighorn to 16 as soon as those tires went on. My numbers are hand calculated and my speedometer is dead on with GPS. Weight in the bed does not add up like unsprung weight the truck has to rotate.

I have the sport 20's still with Nitto Ridge Grapplers. My gears 3.21 with the 8 speed, 4x4 and hemi. Florida is some what flat other than the 4 overpasses I go over and my cruise control is half the trip at 75mph and half at 65mph. The MDS does not kick on over 75 in my truck unless its downhill. My average is now 16mpg.

Funny side note though, if I set my cruise to 60mph and leave it there the whole trip, which is murder as half of the trip is a 70mph zone I can get 20mpg according to my dash, which is about 95% accurate compared to my hand calcs most of the time. As soon as I speed up to 70 its goes downhill quick.

 

[iHemiMan]

I’ve got a quad cab but same concept applies tbh. I get about 16 town and 18 interstate


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[joshuaeb09]

I've got LT275/65R20 KO2s(E range) on the stock wheels and 3.21's with MDS disabled. Similarly to William if I go much faster than 70 my MPG falls on its face, but if I keep it at 70 or below on the highway I can get pretty decent numbers. Typically around town I average 12-14 and straight highway I can maintain around 18mpg if there's no traffic. Honestly I don't worry much about MPG and I've got one out of round wheel already so Ill probably be going to 18"s with 35x12.5's eventually when I've either worn out the KO2s or I cant balance out the bad wheel anymore. I've got front 5100's at 2.1 and rear tuftruck 1211's with a 3/4" steel spacer so more of a small lift than really leveled. Also have no front air damn (it got pretty beat up when the truck was stock since it kills approach angle) and no grill shutters(Deleted).

 

[ram1500rsm]

Hopefully the 99 lbs spare in the bed won't push the rear down, i'll take off the factory spare once my 5th wheel gets deliverd, ordered last week, i don't think the factory spare weights half of the tire setup i have haha, i have around 1/2" rake still in the rear, so hoping that new spare/tire won't be enough to give me 100% level, which will prob increase the moving brick level effect
I also have the MDS stuff disabled in my tune, (couldn't take the noise with the aftermarket muffler i have) and i've added 2* to the 65-70 mph timing cruising range area in it , i haven't done extended long trips yet, just have had the truck for a couple of months, but 18 MPG wouldn't be bad at all.

 

[Pull Ya]

It doesn't take much weight in the bed to make it squat a little. I installed a set of Airlift 1000's on my truck to cure that problem. Every time we went on vacation it seem like we(her) ended up with a dozen suitcases and a couple of coolers and God only knows what else in the back of the truck.
Jay

 

[joshuaeb09]

Hopefully the 99 lbs spare in the bed won't push the rear down, i'll take off the factory spare once my 5th wheel gets deliverd, ordered last week, i don't think the factory spare weights half of the tire setup i have haha, i have around 1/2" rake still in the rear, so hoping that new spare/tire won't be enough to give me 100% level, which will prob increase the moving brick level effect
I also have the MDS stuff disabled in my tune, (couldn't take the noise with the aftermarket muffler i have) and i've added 2* to the 65-70 mph timing cruising range area in it , i haven't done extended long trips yet, just have had the truck for a couple of months, but 18 MPG wouldn't be bad at all.

I feel you there on MDS. With my super 10 it was pretty bad.

If you do end up nose high the tuftruck springs will fix that and they're not very expensive. I actually prefer the XHD springs in combination with my 5100's since it rides more like I feel a truck should and less like a car. My ride is very similar to my old mans stock 2500 gasser. I only added the .75" spacer to give me some more rake as I didn't want to run air bags for towing/hauling anything on the heavy side of things.

 

[ram1500rsm]

It doesn't take much weight in the bed to make it squat a little. I installed a set of Airlift 1000's on my truck to cure that problem. Every time we went on vacation it seem like we(her) ended up with a dozen suitcases and a couple of coolers and God only knows what else in the back of the truck.
Jay

Is there a min PSI needed to run the bags ? or can you run them fully deflated ? i like this idea, that's basically as heavy as i'll go if i'm hauling, family stuff when we go camping/vacations,. perhaps some furniture and the like the wife likes to collect here and there, and for $83 and couple of hour of my time installing, that sounds like a winner to me, picking the airlift 1000 system today from my local 4wp

 

[Pull Ya]

I think they recommend something like 8 lbs minimum just so the bags are inflated a little so they don't get caught in between the springs. This is my second set. I also had a set on my 13 and they do a really good job for my purposes.
Jay

 

[6.7CumminsDrvr]

Just around town/short trips i average a pretty consistent 13.3 mpg’s. If its all hwy i can sniff 16 but my truck isnt running a stock tune either. FWIW, i have no complaints on my mileage due to how the truck is set up and how i drive it.

 

[shadowhawk]

I'm hand calculating mpg and logging it in Fuelly. I was getting high 15s with the occasional 16 if I did more highway driving. I started to keep track of avg mph too, but i only started that AFTER I put the new wheels/tires on the truck. Now I'm getting 14mpg, maybe 15 if I do all highway. I was 15.5 on the last all highway trip, but I was also cruising at 80mph. my avg mph was 58mph according to the truck computer. I always reset my trip, and AMPH was taken from that.

 

[quickfix27]

@WilliamS, I just recently got the same set-up: 295-60R20 Ridge grapplers with 5.7L MDS and 3.21 gearing crew cab with STD bed. Read several posts regarding the poor combination of 3.21 and 35s. After actually driving it, it does feels a bit slower off the line, but don't think it's as sluggish or as big of an issue as many posts assume. Plus i am really happy with the ride quality and look --- so no worries there.

I was more surprised with the hit to mpgs with 4" lift and 35s. Thought it would be closer to a 2-3 mpg hit...not upwards of 4-5 mpgs.

I have only driven it about a week now, but the little city driving is averaging 12-13mpg. Probably a little heavy on the gas as I'm trying out my new rubber! I've got a long trip next week and will post my hwy MPGs soon.

Wonder what % each factor affects the MPG between the lift (higher profile/drag) vs tire size (weight/width), and air pressure???

The shop put 45psi all around on my 35s. Wonder how much my mpg might improve if I add 5-10psi?

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[69GWC]

Did you get your speedo corrected for the larger tires? If not thats part of your mpg loss.

I have 35s and the 5.7 8sp 3:21s and while I would rather of 3:92s my truck will still spin the 35s and still faster than a Chevy..lol

 

[WilliamS]

@WilliamS, I just recently got the same set-up: 295-60R20 Ridge grapplers with 5.7L MDS and 3.21 gearing crew cab with STD bed. Read several posts regarding the poor combination of 3.21 and 35s. After actually driving it, it does feels a bit slower off the line, but don't think it's as sluggish or as big of an issue as many posts assume. Plus i am really happy with the ride quality and look --- so no worries there.

I was more surprised with the hit to mpgs with 4" lift and 35s. Thought it would be closer to a 2-3 mpg hit...not upwards of 4-5 mpgs.

I have only driven it about a week now, but the little city driving is averaging 12-13mpg. Probably a little heavy on the gas as I'm trying out my new rubber! I've got a long trip next week and will post my hwy MPGs soon.

Wonder what % each factor affects the MPG between the lift (higher profile/drag) vs tire size (weight/width), and air pressure???

The shop put 45psi all around on my 35s. Wonder how much my mpg might improve if I add 5-10psi?

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I’m on 295/65-20 so a bit taller but I agree the trucks has plenty of grunt with the 3.21. The off the line is a tad bit slower but the 8 speed does all the guess work giving me all the power I need when the hammers down. Im not even lifted yet, just a level [emoji51]

 

[quickfix27]

Yeah, I've got 295/65R20 Nitto Ridge Grapplers as well and love them! Guess I should stop rounding down my tire size to 35s.

Did you calibrate your speedo with new tires? I got the Hypertech speedo calibrator that the shop adjusted after my lift and tire upgrade. Wonder how much it made a difference in synching shifting with new tires??? Kinda wish I would have calibrated it a few weeks later so I could determine if there is much difference in performance, other than adjusting speedo.

I’m on 295/65-20 so a bit taller but I agree the trucks has plenty of grunt with the 3.21. The off the line is a tad bit slower but the 8 speed does all the guess work giving me all the power I need when the hammers down. Im not even lifted yet, just a level [emoji51]

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[quickfix27]

295/65R20 Nitto Ridge Grapplers

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[WilliamS]

Yeah, I've got 295/65R20 Nitto Ridge Grapplers as well and love them! Guess I should stop rounding down my tire size to 35s.

Did you calibrate your speedo with new tires? I got the Hypertech speedo calibrator that the shop adjusted after my lift and tire upgrade. Wonder how much it made a difference in synching shifting with new tires??? Kinda wish I would have calibrated it a few weeks later so I could determine if there is much difference in performance, other than adjusting speedo.

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I calibrated mine the next drive with my AE tool

 

[quickfix27]

Got a few data points from a recent trip. Bottom line, your hwy MPGs will be highly dependant on your speed.

@ 60mph - averaged 20.2 mpg (after 55 miles)
@ 65mph - averaged 18.4 mpg (after 161 miles)
@ 68mph - averaged 17.4 mpg (after 248 miles)

While these data points are only after 250 miles of driving; they seemed pretty consistent. Plus route was actually pretty hilly with final destination about 3,000 feet higher than starting point, and included a few stops with a drive thru and a gas stop.

Similar results to what WilliamS reported. The sweet spot for best mileage seems to be around 60mph, averaging a surprising 20 mpg! But kick it up to typical highway speeds (70mph+), and you'll likely be closer to 16-17mpg.

After 500 miles of mixed driving (mostly highway) that included multiple stops, and an overnight camping trip, I'm averaging 16.9mpg. Not bad for a 4" lifted crew cab on 35s (5.7L with 3.21 gears).

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