35's with 4.10 gears on DRW

[leeparnell89]

So I ordered my 2022 DRW with 4.10 gears knowing that I would go with 35's pretty quick out of the gate. While waiting for my tires for the first 2k miles or so I got roughly 15 mpg. Got the 35's put on the stock wheels with a 2" steel dually spacer. I now get no more than 12mpg.
I knew I would not get the 19mpg that my 2020 SRW got, but the 4.10's and 35's put my effective gear ratio back to a perfect 3.73. I knew 19 was unrealistic but I expected more than 12, and hoped to stay the same at 15ish with any improvement being a pleasant surprise. I know that these tires are heavier and I'm now a bit wider. I only put Thuren 3/4" lift coils on the front and stock replacement overland shocks on all 4 corners so after sag and settling, I'm effectively at stock height. Truck is a laggy pig and feels the same as my cousins 2020 SRW w/ 3.73's and 35's (not to mention his is loaded down with flatbed and every farm tool known to man). My main driving is 60-70mph county roads, flat terrain of North Central Texas. Air pressure is where it's supposed to be according to manufacturer spec. Tires are E rated mastercraft courser MXT 35x12.50r17.

So, was expecting to at least stay the same at 15mpg unreasonable? I suppose I thought the larger heavier tires but gear "correction" would cancel each other out.
Is it unreasonable to think that I might not have gotten the 4.10 gears that I ordered? It's on my build sheet so this feels pretty unreasonable to me.
Does anyone else have a 5th gen DRW with 4.10's and 35's?

These are all non-towing, empty truck tanks hand calculated and not the dash lie-o-meter. Very little if any idling.

Am I crazy for thinking I could cheat the system? lol

 

[MikeXM]

You got the HO?
12mpg average sounds about right for me. But I don't live in a flat area though. Running 33s on 3.73.
I can get 15mpg if only highway at 65mph. 75 is much lower.

From what I have read here, there is no difference in mpg between 3.73 vs 4.10. Looks like there is more variation truck per truck. Could be driving habits though.

 

[leeparnell89]

You got the HO?
12mpg average sounds about right for me. But I don't live in a flat area though. Running 33s on 3.73.
I can get 15mpg if only highway at 65mph. 75 is much lower.

From what I have read here, there is no difference in mpg between 3.73 vs 4.10. Looks like there is more variance truck per truck. Could be driving habits though.

Nossir, SO with 68rfe. I suppose I just thought there would be a difference because my SRW with 3.73's got 18.5-19. Same driving habits, same roads. Same truck, same engine/trans, both 3500 long bed 4x4. Just 2 extra wheels on the new one.

But I hear the dually fenders are a hell of a drag, I suppose I should just be grateful that I got the 50gal tank so I don't have to stop for fuel as often lol. This 2022 may have a rougher break-in period. I bought my 20 off the lot with a few hundred miles on it. This 2022 came straight to me from Saltillo, so it was never test driven by different folks.

 

[MikeXM]

Oh... Again, based on what I have read here, the SO is usually way better in term of mpg. So... Your numbers could actually be low as you suspect?

Lets see other DRW SO owners have to say.

 

[tchur1]

So I ordered my 2022 DRW with 4.10 gears knowing that I would go with 35's pretty quick out of the gate. While waiting for my tires for the first 2k miles or so I got roughly 15 mpg. Got the 35's put on the stock wheels with a 2" steel dually spacer. I now get no more than 12mpg.
I knew I would not get the 19mpg that my 2020 SRW got, but the 4.10's and 35's put my effective gear ratio back to a perfect 3.73. I knew 19 was unrealistic but I expected more than 12, and hoped to stay the same at 15ish with any improvement being a pleasant surprise. I know that these tires are heavier and I'm now a bit wider. I only put Thuren 3/4" lift coils on the front and stock replacement overland shocks on all 4 corners so after sag and settling, I'm effectively at stock height. Truck is a laggy pig and feels the same as my cousins 2020 SRW w/ 3.73's and 35's (not to mention his is loaded down with flatbed and every farm tool known to man). My main driving is 60-70mph county roads, flat terrain of North Central Texas. Air pressure is where it's supposed to be according to manufacturer spec. Tires are E rated mastercraft courser MXT 35x12.50r17.

So, was expecting to at least stay the same at 15mpg unreasonable? I suppose I thought the larger heavier tires but gear "correction" would cancel each other out.
Is it unreasonable to think that I might not have gotten the 4.10 gears that I ordered? It's on my build sheet so this feels pretty unreasonable to me.
Does anyone else have a 5th gen DRW with 4.10's and 35's?

These are all non-towing, empty truck tanks hand calculated and not the dash lie-o-meter. Very little if any idling.

Am I crazy for thinking I could cheat the system? lol

IDK how much you care to read but a ton of anecdotal MPG claims in this thread.

HO vs non-HO MPG

I've seen many reviews where it looks like there is no difference in MPG for both models, either loaded or empty. But I've never seen a direct comparison either so it is hard to know for sure. Anyone has seen such a review? Or have any info on the subject? TIA

hdrams.com

Oh... Again, based on what I have read here, the SO is usually way better in term of mpg. So... Your numbers could actually be low as you suspect?

Lets see other DRW SO owners have to say.

I think "way better MPG" is overstating it a bit. There may be a nominal difference between SO and HO but it seems to vary a ton from one person to the next.

 

[Darkone]

Have you recalculated your speedometer? If it’s off your calculations will be off.

 

[Drumminguy81]

not completely relevant but these are my experience, my parents have a 21 drw HO 4.10s stock they average 13-14mpg at best. I have a 20 drw HO 3.73, with stock wheels I was getting 16-17mpg. went to 35" mud tires and now see 14-15mpg. speedo corrected. the biggest factors i have found with my current set up is speed. i can get it up to 17mpg if i stick to 55mph but at 75 it drops to 13mpg.. personally I think 12 on your truck is about what i would expect.

 

[IndyRamMega]

I might have missed it but did you recalibrate your speedo? Mines an HO with 4.10 and 33" tires and I get around 15.5 unloaded at 70 mph....1750-1850 rpms seem to be the best for mpg's but I run right at 2k @ 70.....I get 12 while towing 10k....

Also what's your odo at? If you're not above 8-9k you're truck still isn't broken in yet ...

 

[Firebird]

A dually and fuel economy are diametrically opposed

 

[H3LZSN1P3R]

If you have not recalibrated the speedo it will affect shifts and many ither things leading to poor milage and performance

 

[Bombaman]

A dually and fuel economy are diametrically opposed

I've seen some people running just a single inner, which should be pretty fuel efficent haha

 

[gimmie11s]

Have you recalculated your speedometer? If it’s off your calculations will be off.

This..

You are traveling more miles than your trip meter is indicating so when you hand calc, your numbers will be off with the larger tire.

 

[leeparnell89]

Have you recalculated your speedometer? If it’s off your calculations will be off.

I might have missed it but did you recalibrate your speedo? Mines an HO with 4.10 and 33" tires and I get around 15.5 unloaded at 70 mph....1750-1850 rpms seem to be the best for mpg's but I run right at 2k @ 70.....I get 12 while towing 10k....

Also what's your odo at? If you're not above 8-9k you're truck still isn't broken in yet ...

If you have not recalibrated the speedo it will affect shifts and many ither things leading to poor milage and performance

This..

You are traveling more miles than your trip meter is indicating so when you hand calc, your numbers will be off with the larger tire.

I am ashamed to admit that I didn't even consider this. I'd been doing it in my head for speed, but didn't consider the implications for the ECU and speedo/tach. Went out and recalibrated with AlfaOBD this evening and took about a 30 mile drive. It wasn't a complete new truck, but it was certainly an improvement. I'll hook back up to it and force a relearn in the next couple days when I have time to take it for a decent drive. I'm right at 8k miles so I should be getting pretty close to broke in.

Leave it to me to not consider the most blatant answer.... As always, appreciate y'alls help.