Considering 2020 3500 Dully over my F350

[Ltngdrvr]

What all are you towing? I would prefer to go with a 2500 it just seemed like it was bottoming out the suspension when I pulled with it. Air bags may help but doesn't seem like that should be required.

I tow RV trailers for a living, all sizes up to 16K GVWR and actual trailer shipping weights up to 14K.
And, my truck only has air bags...

 

[Ltngdrvr]

And, so many people suggest dropping tire pressures for better ride, but when you are towing dropping tire pressure means reduced tire load capacity, not what you want for towing.
And, changing tire pressure back and forth from towing to bobtail is a PITA.

 

[DonFitzwater]

I assume you are pulling a bumper-pull trailer? Are you using a weight distributing hitch?

 

[AH64ID]

And, so many people suggest dropping tire pressures for better ride, but when you are towing dropping tire pressure means reduced tire load capacity, not what you want for towing.
And, changing tire pressure back and forth from towing to bobtail is a PITA.

There are lots of benefits to adjust the tire pressure for the load, and not adjusting the tire pressure has one benefit.. no work required.

What you want for towing is proper air pressure, not overinflated tires. There is a huge difference. On a 2500 the highest RAWR is 6500 lbs, which doesn't take 80 psi on any of the tires offered for that RAWR. For the 6000 lb RAWR trucks with 17" wheels they do take 80 psi for 6,000 lbs thou. With the 18's they need 70 or 75 depending on the tire size to hit the 6,500 RAWR and 60-65 for the 6,000 RAWR. Your avatar truck appears to be a CCSB with 18's, which I think has a 6,000 RAWR. So if you have 265/70R18's you only need 65 psi and with 275/70R18's only 60 psi (which I think will set off the low psi light ). Running commercial you likely have to be far more concerned with placard axle weight ratings than most of us do for private use only where we can go more off of tire limits (at least here in Idaho).

Yes it can be a PITA, and the number of miles between loads will dictate if I change my pressure or not.. but you would be hard pressed to ever find me running 80 psi in the rear tires for more than a few miles unloaded. I don't like the lower traction, improper tire wear, and harsh ride.

As you can tell, I'm not fond of too much pressure My truck is currently sitting at 55/35, and I have enough to add 500lbs of payload/TW without adjusting air pressure. I'd go to 30 psi for the weight, but that's lower than the recommended minimum of 35. I do go lower for slow speed dirt road driving, as low as 25 in the rear depending on the road/speed.

Think how bad your 2500 would ride if you always had max pressure in the airbags.

 

[R.Taylor]

And, so many people suggest dropping tire pressures for better ride, but when you are towing dropping tire pressure means reduced tire load capacity, not what you want for towing.
And, changing tire pressure back and forth from towing to bobtail is a PITA.

It ain't that bad airing up and down... I'm only towing maybe 8 times a year when chasing Tuna up or down the West Coast. Only takes a minute, No rush here.

 

[Tuesdak]

Agreed that it is somewhat a waste of money to trade in. But who doesn't want a new truck. Values are really high right now on trade ins getting $8k more than what was offered to me in May and have 10k more miles on the truck. Appreciate that break down on fuel cost.

Weird and unusual isn't it. I see the same $8K KBB value increase on my 2018 RAM over the past year. Used anything is going for a high price as well as RV's. New HD trucks are flying off the lots pretty fast.

I suggest you drive the HO Aisin and one of the 68RFE trans trucks. Stomp it from 60 MPH and see what one you like better. Also from a stop and see if there is much throttle delay. (Way improved for 2020 over my 2018.) Also drive a 3500 with the rear air and one without over some bumps: you will feel the difference. Even a DRW rides better with air than the SRW without!

MPG... Don't get me started on TCO for a diesel. Only have a diesel because I have some serious grades where a HEMI would scream for an extended time and likely blow something up. There is no economy left in a diesel with ~$10K higher initial cost, higher fuel cost, more oil and more "real expensive" filters to change... It's a fine line towing vs. DD where a diesel starts to recover it's initial cost the more of the miles are towing. As shown a 3.7 MPG difference is only half of the initial diesel engine cost in 100K miles.

 

[Cummins12V98]

There are lots of benefits to adjust the tire pressure for the load, and not adjusting the tire pressure has one benefit.. no work required.

What you want for towing is proper air pressure, not overinflated tires. There is a huge difference. On a 2500 the highest RAWR is 6500 lbs, which doesn't take 80 psi on any of the tires offered for that RAWR. For the 6000 lb RAWR trucks with 17" wheels they do take 80 psi for 6,000 lbs thou. With the 18's they need 70 or 75 depending on the tire size to hit the 6,500 RAWR and 60-65 for the 6,000 RAWR. Your avatar truck appears to be a CCSB with 18's, which I think has a 6,000 RAWR. So if you have 265/70R18's you only need 65 psi and with 275/70R18's only 60 psi (which I think will set off the low psi light ). Running commercial you likely have to be far more concerned with placard axle weight ratings than most of us do for private use only where we can go more off of tire limits (at least here in Idaho).

Yes it can be a PITA, and the number of miles between loads will dictate if I change my pressure or not.. but you would be hard pressed to ever find me running 80 psi in the rear tires for more than a few miles unloaded. I don't like the lower traction, improper tire wear, and harsh ride.

As you can tell, I'm not fond of too much pressure My truck is currently sitting at 55/35, and I have enough to add 500lbs of payload/TW without adjusting air pressure. I'd go to 30 psi for the weight, but that's lower than the recommended minimum of 35. I do go lower for slow speed dirt road driving, as low as 25 in the rear depending on the road/speed.

Think how bad your 2500 would ride if you always had max pressure in the airbags.

Not many understand the many benefits of running “proper” tire inflation. Many say “ I run what the tire says” then in the next breath are complaining about tire wear and ride quality.

PITA? Not hardly on a SRW. DRW that would hold more water.

I run my DRW 80 fronts always because of weight and allowing for turning wear. Rears 65 running full RAWR of 9,750#. BobTail I drop to 30 even tho the chart stops at 35.

 

[NIsaacs]

And, so many people suggest dropping tire pressures for better ride, but when you are towing dropping tire pressure means reduced tire load capacity, not what you want for towing.
And, changing tire pressure back and forth from towing to bobtail is a PITA.

I agree. When you haul commercial you can't be messing with air pressure. That would take forever to air down and air up 8 tires. When I am on a serious haul, I might haul 3-5 loads a day. Where you going to find air?

I run 60-60 on my truck with 285/75x16's and 100 psi for the trailers, 215/75x17.5 or 235/75x17.5's. I am hard on tires but changing air is not going to happen.

For personal use, proper air inflation is a good plan.

 

[JR]

Running 50-100 miles at a crack over inflated isn't going to make or break a tire as long as there are enough miles being run in between at the proper-ish inflation.
I run my rears 65 from spring to fall excluding heavy loads.
In the winter months when I use my truck the least I do run lower rear pressures. Partly for wear and partly for traction. I don't mind airing up/down during the winter months. My overall miles tend to be significantly less than spring through fall.

 

[AH64ID]

I agree. When you haul commercial you can't be messing with air pressure. That would take forever to air down and air up 8 tires. When I am on a serious haul, I might haul 3-5 loads a day. Where you going to find air?

I run 60-60 on my truck with 285/75x16's and 100 psi for the trailers, 215/75x17.5 or 235/75x17.5's. I am hard on tires but changing air is not going to happen.

For personal use, proper air inflation is a good plan.

Use certainly does play a role. I would be doing the same thing you do in your shoes.

If I were to drag a trailer 1,000 miles then run home bobtail I’d adjust the pressure. Heck I’ve even done that for shorter trips.

I have also put an air compressor under the bed of my truck so I can air up whenever needed, or fix flats as I carry a plug kit too.

 

[Wiredawg]

I think this thread may have already run its course and many good reasons to not trade trucks based upon mpg pay back that may never happen.

I guess OP generally likes the truck as he picked it out to begin with. My 2017 Ram seldom regens, except when I idle a lot dropping off and picking up trailers. At speed, both unloaded and loaded, my truck generates enough heat to keep the DPF clean. At least for Ram, I believe engineers changed regen philosophy and programming to do regens early and not when DPF is higher percentage loaded.

Everyone likes a new truck, and certainly get one if you want it, but you may just want to differentiate between your want and need. Very easy to analyze... make a chart with as many attributes as you can think of and assign a weighting factor, more emphasis on whatever is more important to you. I think your mileage numbers are right in the realm of reasonable. Or, if the itch is really bad, go git you a new truck... don't underestimate want as a good reason.

Christmas Cheers,

 

[Cummins12V98]

I have to ask, is the word "DULLY" correct??? I have always called them a "DUALLY"

 

[AH64ID]

My 2017 Ram seldom regens, except when I idle a lot dropping off and picking up trailers. At speed, both unloaded and loaded, my truck generates enough heat to keep the DPF clean.

I’m quite sure your truck regens as much as the rest of ours, which is at least every 24 hours of engine run time. It’s just seamless under normal circumstances and you only know when those fail and the DPF gets full or nearly full.

 

[RammerJam]

Unless you had less than 24 hours on your engine when stuff fell off, or other modifications not mentioned, you had more than 1 regen and you just didn't notice them. They are very seamless 13+. Even when I know my truck is in a regen because of my CTS2 I cannot tell by looking at anything on the dash. The truck only notifies you of a regen, pre 19, if its unable to complete a regen and the DPF gets near full. If regens complete normally there is zero indication to the driver, and they occur at least every 24 hours of engine run time.

I'm talking the kind that flashes in the EVIC and tells you not to turn the truck off, etc. Got one. Just one. Right around 17k

The other kind, the 'passive' regen? Sure, I'd get the burnt plastic smell every now and then but I'm not sure those count.

 

[AH64ID]

I'm talking the kind that flashes in the EVIC and tells you not to turn the truck off, etc. Got one. Just one. Right around 17k

The other kind, the 'passive' regen? Sure, I'd get the burnt plastic smell every now and then but I'm not sure those count.

Those aren’t passive regens, they are still active and the same kind as the EVIC notification. They count just the same. Take your engine hours and divide by 24. That’s the minimum number of active regens you have had.


Passive regens are simply high enough exhaust temps to clean the DPF without added fuel into the exhaust stroke. They will reduce the requirement of active regens, but not past 24 hours of engine run time. You could be running at 900° in the DPF for 24 hours and still go into an active regen. There will not be an indication on the dash.

On my truck I have never seen an EVIC indication of a regen, but it goes into active regen every 24 hours as indicated on the CTS2. The CTS2 only indicates active regen. I just rolled 800 hours yesterday, so I have had a minimum of 33 active regens.

 

[RammerJam]

https://www.turbodieselregister.com/threads/passive-regeneration.260723/

 

[AH64ID]

https://www.turbodieselregister.com/threads/passive-regeneration.260723/

Exaxtly, it even talks about the 24 hour run time reset after each active regen. You will not got past 24 hours of engine run time without an active regen on a 13+ truck.

Passive regen is great for DPF health, life, and fuel economy but it will not replace the 24 hour run time active regen.

 

[Wiredawg]

John,

Maybe I should have been clearer, my 2017 seems to regen even less than my former 09. Also, I have a CST2 monitor that signals everytime I regen. Although, as I said I see it when i idle a lot, seldom see it pulling. Might be my mistake in how DPF works, but thought it self cleaned of sorts with higher exhaust temps. I also monitor exhaust back pressure, which i assume is the pressure differential measured before and after the DPF.

Again, haven't studied or tracked this hard, just general observations.

Christmas Cheers, Ron

 

[TFucili]

It's a bit confusing, but even if the duty cycle is keeping the DPF clean with Passive Regen, it will do an Active Regen every 24 engine hours whether it needs it or not. So, two types of Active Regen, first based on restriction, and second based on 24 hours "Hobbs time". There, I propose we call it a "Hobbs Regen". Can I get a second? All in favor say, "Aye!".

 

[AH64ID]

Ron,

Your 2017 will absolutely regen less frequently than your 2009, and use less fuel per regen too. SCR trucks have many advantages. The regen is also much shorter, rarely longer than 10 minutes for me.

On your 2017 anytime EGT3 is above 600°F you are in some level of passive regen, so it is passively cleaning while pulling. I see around 700°F at 70mph bobtail, so towing would be higher.

Exhaust back pressure is the pressure in the exhaust manifold, so either drive pressure or exhaust brake pressure.

DPF pressure is the pressure delta across the DPF.

You are correct in how the DPF cleans itself without fuel, but that will not ever negate the minimum active regen at 24 hours of engine run time.

My dad also has a CTS2 on his 2017 and has never seen it indicate a regen, but I’ve seen it in his truck. He just hasn’t noticed it. I would guess it’s easier for you to notice the green light at idle than concentrating on the road. It’s just happenstance that it’s at idle, unless you’re idling a lot. They will not regen in park unless it a been idled too much and cannot complete a moving active regen, I’ve seen this once on dads truck and never on mine.