Dodge Ram 2500 PSI

2014 Ram 2500 Tradesman EVIC display and TPMS waring light. Demanding 80 psi in the rear tires even if not necessary or optimal.

Oscar sent me a message asking the following TPMS question.

Question:

“I have a question involving the TPMS setting on my truck… I need to change the threshold on it; I have taken it to a dealer but they don’t want to do it.”

Answer:

Oscar,
My understanding is that dealers will not, or cannot, adjust TPMS thresholds on a Ram 2500s anymore, supposedly Ram removed their ability to make adjustments to the TPMS. That is what I was told by a local dealership when I asked, and they said the tried (I believe them), a few years ago. Idiotic, but even if dealers could still adjust the TPMS thresholds I’d not be surprised if most refused, given the highly litigious society we’ve created.
My very expensive solution more than a year ago was to buy a professional scan tool that allows me to reset the thresholds (and much more) on my two Ram Cummins 2500 trucks, though now there are cheaper options. Before buying the tool I just lived with the light on. (I frequently write light-truck tire evaluations, have several sets of wheels, and not all of them have TPMS sensors.)
Backgrounder and Addition Comments
UNDER-INFLATED TIRES ARE DANGEROUS

As many late model Dodge Ram 2500 truck owners have discovered, Ram Trucks eliminated the light-load TPMS driver-selectable feature after 2012, and began requiring maximum pressures in the tires regardless of the load to keep the TPMS light off.

2012 Ram 2500 with light load TPMS feature

That is fine if you are someone who uses your heavy-duty pickup to haul or pull big loads most of the time (the exception), but asinine if you are one of the many who moves big weight infrequently. Maximum pressure is required for safe operation with truly maximum loads, however is not required, and is actually detrimental, for moderate or minimum loads. The recommended and safe maximum pressure is also dependent on the specific tire size, rating, and construction. Tire and Rim Association load inflation charts exist for a reason.

Requiring the maximum PSI (or near max.) for both axles, particularly the rear, when loads are light is ridiculously idiotic and negatively impacts handling, traction, tire wear, and ride quality… but those things seem not to matter any longer; avoiding liability from irresponsible drivers is likely paramount.

2012 Ram 2500 tire pressure placard for heavy AND light loads

My preference for the standard G56, 6-speed manual transmission (lower engine power rating, and discontinued for 2019) behind my Cummins Diesel 6.7L engines means that both of my Ram 2500 trucks—a 2014 crew cab and a 2017 regular cab—are essentially the same as a 3500. The obvious exception being that late-model 2500s have rear coil springs instead of rear leaf springs. However, there is a TPMS system difference as well.

For those that don’t want to run maximum tire pressure with minimum loads, a strong argument can be made to choose a Ram 3500 over a 2500, because the 3500 TPMS system is informational, not a nagging nanny, and allows using lower pressures without a TPMS idiot light. At least that was how the 3500s pickups worked up to 2018, I don’t know how the 2019 or 2020 models function.

James Langan

Copyright James Langan/RoadTraveler All Rights Reserved 

 

 

 

Dodge Ram Cummins Flatbed Camper MPG

Backgrounder

A recent Nevada Highway 95 trip from Northern Nevada to Southern Nevada, and back, a very familiar route, produced some interesting data. People often make contrary statements about shared fuel economy information, generally well intentioned but not always accurate, including:

1) My similar truck/camper does much better (or worse). 2) An aftermarket engine tune would produce superior results (doubtful but possible). I could write several such hearsay proclamations.

Let us remember that similar is not the same, and this includes engine tunes, programming, and power ratings. Modifying engine performance is not an option as long as I want to keep my emissions equipment on my truck and continue registering it in the zip code where I live. However, my 350 horsepower, G56 manual truck has plenty of torque and power, and if I wanted more I’d likely regear the differentials.

Now, let’s review some fuel economy 101.

Everything that is different can matter, including:

-Driver

-Tires

-Speed

-Engine output (also brand, configuration, etc.)

-Gearing

-Terrain/conditions

-Weight (less critical than many think, depending on the outfit)

However, the two big ones often not fully appreciated are:

Engine speed: pumping losses

Vehicle speed: aerodynamic losses

Engine pumping losses are of minimal concern for this rig. The 2017 Ram/Cummins has the tall factory 3.42:1 gears, a 6-speed manual transmission, and runs 35-inch tires, resulting in low rpm in overdrive.

The aerodynamics are horrible. This is a heavy-duty truck with a big winch bumper/grille guard, sliders, and a flatbed with mud flaps; these are important details. However, the frontal area and drag coefficient of the truck camper (and truck) are a huge factors.

It is possible to get similar (or better) mpg with a heavier truck and trailer combination that is more aerodynamic; that’s how critical wind load and speed are.

Fuel Economy Data

The test below was informal, if you want something more detailed, with additional focus on controlling variables, you’ll likely enjoy this post: Tread Matters

Southbound: Fernley to Beatty, Nevada

Vehicle: 2017 Ram 2500 Cummins/6-speed manual

Date: March 2, 2019

Distance: 295.6 miles (odometer corrected)

Cruising speed, where legal: 65 mph

RPM: 1,650

Approx. gross weight: 11,500 pounds

MPG: 13.47

Northbound: Las Vegas to Hawthorne, Nevada

Vehicle: 2017 Ram 2500 Cummins/6-speed manual

Date: March 4, 2019

Distance: 302.0 miles (odometer corrected)

Cruising speed, where legal: 63 mph

RPM: 1,600

Approx. gross weight: 11,500 pounds

MPG: 13.26

Speed Eats MPG

Because the terrain and conditions over Nevada Hiighway 95 have repeatedly given better fuel economy going southbound than northbound, I intentionally reduced my speed going north to try to limit the difference. It worked, two mph made a difference. My educated estimate is that at 65 mph, fuel economy would have been in the high twelves on the trip north, and going as fast a 70 mph would have droped mpg into the mid to low twelves.

Want a quick example of how much speed and conditions matter? The same outfit when it weighed less and was slightly more aerodynamic with the stock front bumper, cruising almost completely at a constant 75 mph on Interstate 80 across Northern Nevada, Elko to Reno, including maintaining 75 mph up and over mountain passes, and a bit of off-highway travel to camp, yielded 11.57 mpg over a distance of 300.4 miles. Considering the use and conditions, that was an appropriate result, inline what was requested from the chassis.

Moosnrise, long exposure, White Pine County, Eastern Nevada, 2018.

James Langan

Copyright James Langan/RoadTraveler All Rights Reserved

Resource linK:

Hallmark Campers