2500 6.4 35 or 37 inch ire MPG

[MasonD21]

If you went with a less aggressive tire you wouldn’t see much of a difference... and you’d be done with those horrible firestones


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Agree. You're good to go on getting tires other than those Firestones (although they are a surprisingly good tire). I suspect your MPG dropped so hard because you went from a highway tire to a mud tire. Lot more rolling resistance with those large tread lugs hammering the road, not to mention larger diameter.

 

[River19]

Been running 35" Trail Grapplers for 34K miles and they are about cooked.....295 65 20s, 3.73s and I ave ~11-12mpg locally and about 10-10.5mpg when I tow our horses. Best trip was a 3400 mile stretch with 4 people and 4 mountain bikes hanging off a hitch rack from MA to NC.....somehow got 17.x mpg.....unreal.

Thinking of sticking with ~35" but may drop down to 285 65 20 to go with Duratracs......I can stick with 295 65 20 and go with Grabber X3s......decisions

 

[RAM_Designs]

I average somewhere in the 11's with my 37's on stock Power Wagon suspension and 3.73 gears. I drive a lot of highway miles though, keep it in 5th unless I'm going 75+.

 

[DesertCrushinPhil]

My 2015 Ram 2500 6.4 and 3.73 ratio has the meanest 37s out there. Toyo 37x13.5 r17s with Hutchinson beadlocks. 140lbs of steel belted radial and wheel. Built tough for the US military's requirements.

I get 10 city, 13 hwy which is not bad at all. Stock tires get 13 city, 18 highway empty. For heavy towing, 10000+ I put the stock HTs back on, otherwise its asking for trouble from the truck gods. I would estimate a set of 37s lowers tow rating 20% just like the mpg.

 

[DesertCrushinPhil]

I will definitely get a Cummins next time as seeing the range reduced to 230 miles on the 6.4 when climbing desert mountains is not good. Mind you that's 37s and no trailer. My stomach tightened up the first time away from Vegas, climbing and watching the needle go down. She's a BEAST but thirsty for the petrol!

 

[Rambojoe]

Nitto Terra Grappler G2s, 35x11.5x20. The dash says 11-12 average, still need to hand calc it to verify. 34.53 diameter, 11.42 wide.

 

[Booner21]

Same here 12.5 to 11.5 everyday driving cooper st maxx 35x12.5 2in level. The solo muffler delete did more forthe decrease than the tires just can't keep my foot out of it. Remember it isn't miles per gallon it is smiles per gallon[emoji41]

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[McBroom]

Same here 12.5 to 11.5 everyday driving cooper st maxx 35x12.5 2in level. The solo muffler delete did more forthe decrease than the tires just can't keep my foot out of it. Remember it isn't miles per gallon it is smiles per gallon[emoji41]

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That Solo Exhaust Delete Kit is simply badass. I love mine!


I love my truck!
Blue Mule 18 Ram 4x4 C/C
Tradesman Power Wagon

 

[RAM_Designs]

37" tires with stock PW suspension, and 4.88 gears...getting 12-12.5mpg on the EVIC.

 

[olyelr]

37" tires with stock PW suspension, and 4.88 gears...getting 12-12.5mpg on the EVIC.View attachment 159803

****, thats all I got on the stock duratracs

 

[JohnnyMac]

On my '14 with the 6.4 I put a 3.5"f /2"r lift on it with 35's and lost about 1mpg in town and 4mpg on the highway. I'm guessing the lift, tire width and extra rolling resistance was harder on it at the higher speeds. I also think 37's may have looked a little stuffed without going higher on the lift.

 

[Reuben]

I’m getting around 10-11 in town and about 15-16 if I go easy on the highway with 37’s.

 

[AZDRT]

Getting ready to do Thuren 3/1 suspension on my 2500. Already ordered new rims with +20 offset in preperation for 37's. Question is, how will the truck tow with 37's vs 35's?

Currently running a 2" spacer and 35's, tow a 20' enclosed 10k rated trailer, but usual weight is around 7k pounds. I tow the trailer less than once a month, but those trips entail a few thousand feet of climbing.

Debating staying with 35's now, but really love the look of 37's.

2015 6.4 with 4.10 gears, airbags and daystar cradles

 

[olyelr]

Getting ready to do Thuren 3/1 suspension on my 2500. Already ordered new rims with +20 offset in preperation for 37's. Question is, how will the truck tow with 37's vs 35's?

Currently running a 2" spacer and 35's, tow a 20' enclosed 10k rated trailer, but usual weight is around 7k pounds. I tow the trailer less than once a month, but those trips entail a few thousand feet of climbing.

Debating staying with 35's now, but really love the look of 37's.

2015 6.4 with 4.10 gears, airbags and daystar cradles

Oh this is an easy answer. Put the 37’s on. Tow with it. If you dont like it, then regear to 4.88’s or 5.13’s. BOOM.

 

[G. Mcpherson]

It's only Money! LOL

 

[olyelr]

It's only Money! LOL

Exactly. Just look at it like this... instead of the truck costing $57k it cost $59k. Well worth it imo!

 

[AZDRT]

Oh this is an easy answer. Put the 37’s on. Tow with it. If you dont like it, then regear to 4.88’s or 5.13’s. BOOM.

The point of forums is to share knowledge, not just tell everyone when they ask a question to spend thousands, and if it doesn't work spend a couple more...

 

[olyelr]

The point of forums is to share knowledge, not just tell everyone when they ask a question to spend thousands, and if it doesn't work spend a couple more...

Im guessing you didnt sense the sarcasm?

If your towing experience right now with the 35’s is acceptable, it might not be with 37’s. Its all personal preference. But you know darn well its gonna be noticeably worse.

BoldAdvetures tows around an airstream with his stock 4.10’s and 37” mudders. He claims its acceptable. I, however, could hardly stand the stock 33’s and 4.10’s, and with heavy 35’s its just that much worse.

Ive pretty much decided im not doing 37’s until I regear.

 

[pwjouster]

if you are having issues with 4.10 and 35s...you need to go try any other factory Suv or truck on 35s.

the real issue you might be having is the transmission tuning if your bothered that much with 35s on a stock powerwagon.

im about to jump to 37 and i never plan on re-gearing as long as its my road warrior. Looking for engine and trans tuning to keep me in the right gear.

i just hate the way the truck lugs around in 6th gear all the time. Yet i know the 8 speed is doing the same thing

 

[olyelr]

if you are having issues with 4.10 and 35s...you need to go try any other factory Suv or truck on 35s.

the real issue you might be having is the transmission tuning if your bothered that much with 35s on a stock powerwagon.

im about to jump to 37 and i never plan on re-gearing as long as its my road warrior. Looking for engine and trans tuning to keep me in the right gear.

i just hate the way the truck lugs around in 6th gear all the time. Yet i know the 8 speed is doing the same thing

Oh I am on board with ****** trans tuning for sure. But, I sure as hell dont need to be at 1500 rpm’s when I am cruising. The truck can hardly handle it unless its a flat road or slight downhill slope. I am never on a freeway.... think in the 3 years of ownership I was on a 70mph freeway for like one hour.

When I drop the trans to fifth gear when cruising and the rpm jumps to 2000, everything is much better. I would like that to be overdrive (4.88’s or 5.13’s would do that), and then add the extra gear down low. I know it would do wonders.