Poor gas mileage and handling

[rhaycock]

I have a 2021 1500 Limited 4wd Hemi 5.7 etorque and I am pulling a Grand Design Imagine 17mke 4700lb dry 5700 fully loaded. Tongue weight is currently 630lbs and I have a Fastway E2 WDH.

We just travelled from Arizona to Pennsylvania and saw a range in gas mileage from 6.5mpg to 9mpg, mostly on the lower end around 7 mpg.
We are also seeing more sway with Transport trucks and wind.

Previously we owned a 2020 1500 Warlock 2wd Hemi 5.7 and drove it from Arizona to Colorado and got 10-12 mpg. Sway was good on this truck.

Not sure why there would be such a big difference, I expected a little lower with MPG based on the 4wd but not what we are seeing. I also thought with the heavier truck and capacity increase we would have seen better handling of the sway/wind not worse.

Any suggestions would be welcome

 

[Farmer Fran]

Did you reset up your hitch system on the new truck or just transfer it? Did you follow the directions on how to hook up with the Limited? 22" wheels and 3.92?

 

[rhaycock]

Yes, updated the hitch system and followed the guidance that was given by RAM, put in tire change mode before setting everything. The front fender only changed by 3/4" without WDH and then came back to normal after the weight distribution hitch was applied.

Yes on the 22" tires and 3.92 Dif. Also fyi the warlock was 20in and 3.21 Dif.

 

[crash68]

If you have a CAT scale that you can run the truck across, check the WDH set up that way. Run the truck/trailer fully loaded with the WDH engaged across the scale then drop the trailer and weigh just the truck. With those numbers you can check the actual tongue weight %. Going by measurements will get you in the ballpark but actual using the actual weight will let you dial it in better.

 

[Riccochet]

Does your truck have the Goodyear Fortera SL tires? They're absolute trash, soft side wall and soft compound.

 

[Farmer Fran]

I always go back to the hitch system first, but that is just me. As for the MPG, it sounds about right. The 5th Gen Limited is a heavy truck, pair that with 22s and 3.92s and the MPG can be bad.

 

[Farmer Fran]

Does your truck have the Goodyear Fortera SL tires? They're absolute trash, soft side wall and soft compound.

He should have the EAGLES and I had zero problems towing an 8000+ pound load with them on factory pressure.

 

[Firebird]

I have wondered if it's the air suspension? My buddies 2020 Limited does the same thing, main difference is air suspension

 

[runamuck]

our travel trailer is about 6000# when towing and 28' long. I generally get 8.5-10 depending on the terrain. I set cruise for 68-69. I have air bags at 20# and I add a few pounds to the rear tires. I also swapped out the sway bar to the helwig. tows fine

 

[2019RamInSC]

Not that this helps much. But for comparison.

2019 Laramie hemi 4X4 3.92. Equal-I-Zer Hitch. Trailer 6400 lbs. loaded.

TV and Trailer perfectly level. No sway under any normal circumstances. Very slight sway under heavy crosswind. Flat level ground with cruise at 61 MPH - 11-12 MPG. On a trip with varied terrain. 8-9 MPG. Not out in the Rockies. East of the Mississippi so far.

Payload on Ram is very close to maximum.

I would suspect the WDH. As to MPG. Its a long trip with vastly different topology. So all bets are off.

Have fun!

 

[OC455]

Just throwing it out there, maybe the quality of the gas varies possibly? I always noticed a difference in mileage when I was traveling through the midwest. Always got more mileage per tank...don't know if that makes a difference these days.

 

[b8ascrub]

So I found this thread cause I am having the same issue towing or not towing. 2021 Ram 1500 Bighorn I am averaging 13.8 city and 14.4 highway not towing. When I tow my travel trailer at 4800lbs I average 10mpg. The truck has 3900 miles and I heard it should improve by 5k when it breaks in. However, talking to other ram owners it doesn’t sound right. Could there be a manufacturer issue on the fuel system or ECU? Even when I baby the gas pedal I don’t see any increase. Just changed tires and mpg stayed exactly the same. I only use 89 gas, never put 87 in.

 

[drummerdonny]

I Also have a 2021 5.7 v8 and only get 17mpg . have 1100 miles on it so far. Wonder if it is a software patch ?

 

[Irishthreeper]

Those mpg figures don’t sound right. I had a ‘19 1500 Bighorn with 3.92’s and managed 21.5 on flat I95 doing 70 during one trip. Towing 10k+ I would get 9.5-11.0 on that same stretch. That truck had 18x8’s and was a quad cab so was probably much lighter than OP’s truck.

 

[Farmer Fran]

So I found this thread cause I am having the same issue towing or not towing. 2021 Ram 1500 Bighorn I am averaging 13.8 city and 14.4 highway not towing. When I tow my travel trailer at 4800lbs I average 10mpg. The truck has 3900 miles and I heard it should improve by 5k when it breaks in. However, talking to other ram owners it doesn’t sound right. Could there be a manufacturer issue on the fuel system or ECU? Even when I baby the gas pedal I don’t see any increase. Just changed tires and mpg stayed exactly the same. I only use 89 gas, never put 87 in.

DIC or actual MPG calculations? Is that your actual truck in the pic? A change in wheel/tire diameter can change things dramatically.


E A G L E S

 

[aatk]

Just went from KY to NY through WV - hilly. 20‘ haulmark with a light car inside, so about 6k All up. 2019 limited.

Same deal. Sub-8 mpg and it tows awful. Hated going over 65 and got awful sway when trucks passed me.

My VW did the same tow easier, faster and with over 10mpg average. The only plus the Ram has is it’s easier to back into the driveway because the mirrors are bigger.

 

[b8ascrub]

DIC or actual MPG calculations? Is that your actual truck in the pic? A change in wheel/tire diameter can change things dramatically.


E

DIC or actual MPG calculations? Is that your actual truck in the pic? A change in wheel/tire diameter can change things dramatically.


E A G L E S

It was like that with the OEM rims and tires. MPG didn’t drop too bad since I kept the same size rims.. tires though are a big difference now that I’m running 35’s

 

[drummerdonny]

DIC or actual MPG calculations? Is that your actual truck in the pic? A change in wheel/tire diameter can change things dramatically.


E A G L E S

I have same issue . I cant get to 17MPG even babying the pedal. window sticker says 17 city and 22 highway . Not happy . mostly get 13 to 15 mpg. Somethings wrong ?

 

[Farmer Fran]

S

I have same issue . I cant get to 17MPG even babying the pedal. window sticker says 17 city and 22 highway . Not happy . mostly get 13 to 15 mpg. Somethings wrong ?

Sounds like something is wrong. I get 17 mixed and near 20 now on the highway.

Tire pressure, oil change, windows up, etc...

 

[Jerrybob]

Wow......sure not what I am seeing. I have a 2019 Tradesman.....5.7 hemi....3.92....4x4....crew cab....currently has 16,000 miles......we pull a smaller trailer than you folks.....a 17ft Casita.....only about 3500 lbs fully loaded......I don't use or need a WD on the truck......I consistently get 20 to 22 mpg when not towing......on a recent trip up the Oregon coast.....I got 16 to 17 mpg towing our trailer. My truck is rated at 11,200 lbs for towing.......I also tow a car trailer with a tractor on it at times. I love the mileage I get when towing......my Ram doesn't even know the trailer is back there. Just thought I'd share......