Towing; Numbers Versus Reality - Looking For Experience

[Schoolbus]

Greetings Fellow Cummins Owners,

The bottom line upfront, I do not want this thread to turn into some sort of bashing opportunity against myself or those who respond. I am asking this community because a lot of you push or exceed the limits of your trucks through towing (regardless of trailer type). I also understand upfront that towing a backhoe and a travel trailer are apples and oranges in some ways (such as wind effects). I am not seeking justification to tow this combination, just your experiences, and expertise.

So I just purchased a 2022 Grand Design 390RK which is a big turd for my truck (See signature). By the numbers, I can tow it but my wife and I know that we are at the numerical limits of the truck.

So, here are a few truths:
-Truck scaled at 8640 with a full tank, toolbox, tools, my wife, dog, and son (not me). I added some weight to that to account for my weight and misc items packed in the truck. GVWR is 12,300 and the Cargo capacity is 4110 (from the door). That leaves me about 3450 pounds for hitch weight before I hit the rear axle wt limit and GVWR.
-Trailer has not been scaled yet (I pick it up Friday), but the GD website says dry wt is 14562 and hitch wt is 2794. I know that both are low numbers since I have the 3rd AC and a few other options. GVWR is 16800 which is within the tow rating of my truck (17,010) but is more than I can tow when taken in context of the numbers.
-Based on all numbers, I am limited to 16,000 pounds when traveling. Depending on hitch weight, I will be at 100% GVWR and within a few hundred pounds of GCWR (25,300).
-I have read fellow 390RK owners say their hitch wt % is over 20%. At 22% hitch wt and 16000 pounds, that is at 3500 pounds hitch wt. Those with generators and Washer/Dryer combos are closer to 4,000 hitch wt (I don't have either).
-I am installing a 20k Reese goosneck on it so overall I think that will drop about 50-75 pounds from the hitch wt over a Pullrite and probably 100+ pounds when compared to a traditional hitch. While there are many positive reviews for the Anderson setup, I have seen enough failures during emergency braking or accidents to not go with their setup.

Assumptions:
-The truck's rear axle weight limits are not the axle's limits, but the tire's limits. So this is an area I must be aware of and know I cannot exceed the tire's limits which is 7280 (both tires added together).
-The long bed and long wheel base is going to be an advantage to control the wind's effects on the towed combo.
-I have seen plenty of SRW trucks pulling big 5th wheels and toy haulers (even a few triple axles) which I believe are exceeding the capacity of the owner's trucks.
-The last guy next to me in camp had the exact same truck with a GD 373RES which weighs a little less with more hitch wt. He has a Champion traditional hitch, rollup bed cover, generator, tools, extra 30 pound propane tank, and gas in his bed and he said he has towed it for the last 6 months through the Midwest, north west, and down into Cali. He (about 65 so not young) claims he never felt unsafe or had any issues and I am sure he is over wt by the trucks numbers.
-Pulling it will feel similar to my GD 315RLTS which is 38' behind the hitch and about 12,500 when loaded and rolling.
-That despite being at the max numbers, the truck should still pull this combination safely down the road.

Further information:
-I cannot afford to buy another truck right now (unless someone wants to trade their dually for a SRW). We are full-time living in the trailer so it will sit 90% of the time.
-We are planning two trips from So Cal (San Diego area), one to Sequoa Natl Park, and one through the Rockies to Denver, then to Wyoming and SD (black hills), and back through Denver to So Cal.
-When I retire from the Marines, we are planning to buy a dually before hitting the road for a few years.
-We are also going to upgrade the trailer's axles to 8k axles and disk brakes which will help carry more stuff when behind a dually. Despite the trailer sticker, it will increase the GVWR to 18,000 pounds. This is what GD certifies factory trailers to when upgraded with 8k axles so I know it is fine.

What are your experiences driving SRW trucks with heavy loads?

Thanks,
Scott

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[AK Bob]

Great write-up; nice to see you have done your research.

Your information will help others make the correct and safe decisions when shopping for trucks and trailers.

Unfortunately, I don’t have any experience heavy towing with a single rear wheel truck.

Hopefully, others will chime in.

I have a stock suspension DRW 3500 and tow my Fuzion (GVWR 16500 lbs) close to capacity with Harley or RZR side by side in the rear garage.

I have a 50-gallon auxiliary fuel tank and heavy B&W hitch in the bed.

After three round trips from Alaska to Minnesota and Utah, no complaints on how the truck handles, very stable never felt unsafe or uncomfortable in snow, rain, or wind.

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[CrazyTrain]

I ran my 39’ cedar creek behind my 2017 2500 CCSB, Cummins. 5er is just shy of 16k rolling down the road—3100ish on the pin with a Demco slider.

I had Firestone and Red label bags and upgraded tires good for 4080lbs ea.

I was overloaded by the numbers but never felt unsafe towing under any conditions but was always mindful that I was not driving a dually and was pulling a significant load.

I never hurried. I towed that combo for about a year and upgraded to a dually, just in case.

My $.000002 (adjusted for inflation) is doable, especially since you have plans to upgrade.

You’re starting with a 3500srw, so you’re better off than me.

Off topic here, but I drive my ford ranger loaded with my tools of the trade every day overloaded for the truck.

Half the service vehicles in our area are the same, usually overloaded 1/2 ton vans sagging rears. Not saying it’s the right or wrong thing to do, just an observation.

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[Aboshan]

I have been in the transportation business for 37 years as a driver and manager.

I have a 3500 SRW short bed and have to keep tabs on weights when towing my 5'er.

If you are over the legal limits from your post, it's not by much.

If you understand that and adjust your driving habits accordingly, there shouldn't be an issue in the bigger picture.

In my experience, the only time weight is an issue is if you are rolling down the road overweight where you get pulled over, OR you are at fault for a significant injury/fatality accident.

The other side will most likely look at weight information if it goes to court.

Always someone wanting to make a buck on liability. You know what the truck weighs with gear.

I would get everything hitched up as usual and get it weighed both truck and trailer where you can get at least a separate drive axle weight, then go from there.

If it's within a few hundred lbs. you are good to go IMHO.

Even the scales for the big trucks give you 200 lbs. over what they call max weight before they pull you in.

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[Schoolbus]

@CrazyTrain Thanks for your input.

Two questions:

1. What tires did you find that are rated for 4080 each?

2. What differences did you note in driving the combination between your SRW and Dually?

I know it won't be a like-for-like comparison since I am Leafs and a long bed, but I am curious.

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[Schoolbus]

I have been in the transportation business for 37 years as a driver and manager.

I have a 3500 SRW short bed and have to keep tabs on weights when towing my 5'er.

If you are over the legal limits from your post.

If you understand that and adjust your driving habits accordingly, there shouldn't be an issue in the bigger picture.

In my experience, the only time weight is an issue is if you are rolling down the road overweight where you get pulled over, OR you are at fault for a significant injury/fatality accident.

The other side will most likely look at weight information if it goes to court.

Always someone wanting to make a buck on liability. You know what the truck weighs with gear.

I would get everything hitched up as usual and get it weighed both truck and trailer where you can get at least a separate drive axle weight, then go from there.

If it's within a few hundred lbs. you are good to go IMHO.

Even the scales for the big trucks give you 200 lbs. over what they call max weight before they pull you in.

Thanks for the inputs.

I am hyper-aware of the limits, and I will be interested in my first drive through LA traffic and down the 405 to the five tomorrow during rush hour.

Ugh, I hate Cali drivers.

Any mods I do to my truck are not so I can carry more weight, but the weight I carry can be done more safely.

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[Schoolbus]

So with a brief update. My wife and I love the GD 390RK! It is beautiful inside and the wife and I are very pleased as we full-time in it. The storage is a blessing and a curse; frankly there is just too much of it and you can’t use it. The 7,000 pound axles are just not sufficient for this trailer. We have not even scratched the surface of using it and the trailer is overweight by quite a bit.

I took it to the base scale yesterday and it came in at 26,220! The scale is total weight only so I don’t know the axle breakout weights. Ugh. Now this is setup with living weight and not travelling weight. Since we are in a transition point, I had a lot of excess baggage:

-4 extra batteries, 3 for my truck and 1 from my old travel trailer
-15 gallons of lubricants: truck oil change, ATF +4 for REVMAX Billet VB, oil change of my wife's Jeep and my Firehawk (none completed yet)
-An extra Reese 20k goosebox in the bed (did not fit my frame, went with a PullRite 2600).
-My old self-propelled lawn mower in the bed.
-Full set of cordless tools in a roll-case
-Set of tools (1/2" socket set shallow and deep, hammers, extensions, drill bits, etc)
-Heavy 4k gaming monitor
-Window AC unit
-2 ShopVacs
-Anderson weight distribution hitch
-Some other misc things that are up for sale or headed to storage

I think by getting rid of the above items, I can drop nearly 1,000 pounds. We will have to slim up inside as well by removing clothes, pots, pans, and food stores while travelling to get closer to my desired towing weight. I figure I would want to be at or below 25,000 GCVW which is under the trucks specs. The truck really struggles to get it rolling but does ok once it is moving.

We are taking the combo to Sequoia later this month and that will be a good test run to see how the truck handles it all. I will also be able to find a CAT scale and see what the axel weight breakouts are which will tell me a lot about what steps to take next.

I am considering a regear to get better leverage to get this thing rolling easier. I am thinking of moving to 4.11 gears. Cost is about $1400 minus fluids. I have installed a lot of gears back when I was in Jeeps. I have done everything from a Dana 30 to a GM 14 bolt.

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[CrazyTrain]

@CrazyTrain Thanks for your input.

Two questions:

1. What tires did you find that are rated for 4080 each?

2. What differences did you note in driving the combination between your SRW and Dually?

I know it won't be a like-for-like comparison since I am Leafs and a long bed, but I am curious.

Ridge grapplers 1 size up from stock in 18”.( 285/75-18 gets you a load index of 129) On a 2017 ram 2500.

The difference from drw to dually is night and day on stability. H.O. with 4:10s is also night and day acceleration wise and general ease of towing heavy in general.

I’m trying to find my discount tire bill on the exact size of the tire.

I figured the slight increase in diameter was a good trade for the extra load capacity.

Sorry I did not see this question sooner to get back to you in a timely manner.

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[Schoolbus]

While I would not mind the increase in load index, I think there would be some counter-effort increasing tire size while also dropping to 4.11s.

The increase in rotational mass and tire diameter would reduce the effect I am looking for.

Perhaps with 4.10 gears and my "tuned" truck, it would pull more like an H.O. truck while retaining the SRW configuration.

At least get me through the next 2-5 years until we decide to tour America, at which point the dually will be obtained along with 8k trailer axles.

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[CrazyTrain]

While I would not mind the increase in load index, I think there would be some counter-effort increasing tire size while also dropping to 4.11s.

The increase in rotational mass and tire diameter would reduce the effect I am looking for.

Perhaps with 4.10 gears and my "tuned" truck, it would pull more like an H.O. truck while retaining the SRW configuration.

At least get me through the next 2-5 years until we decide to tour America, at which point the dually will be obtained along with 8k trailer axles.

You are correct on the larger size.

The size and brand, I used, ended up being right at 35” diameter.

It took a little more to get rolling but the load capacity was what I was after.

They looked good as well. It worked. I worked with what I had and then upgraded the whole truck on a whim.

I didn’t care if the dually might be a little more work to deal with in parking lots, etc.

I got exactly what I was after, figuring it may well be my last new heavy truck.

Who knows for sure?

Gear would certainly liven up your truck from 3:42.

As long as you’ll be doing the gear yourself and keeping the truck for a bit longer, the effort will definitely be worth it.

Sometimes, but not often, I miss the longer legs of the 3:42 gear.

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