Am I getting enough of a truck?

[powerscol]

I have a 2023 Solitude 380FLR. GD states that the king pin weight is 3052. I am in the process of purchasing a new RAM 3500 Limited with the Turbo Diesel and the Aisin transmission. The unit I am looking at is a SRW. I know that a dually would be the best choice but I would really rather not have dually. Also, since I live in Northern Illinois, a state which regularly get a fair amount of snow and I have heard from many sources that duallys don't do well in the snow. My question is will this truck be able to safely pull my Solitude?

In a word NO! You will not have the CCW you need. What is the door sticker rated load. You need the dually -peroid. A SRW will not give you the stability you will need. Properly equipped a dually is fine in snow. I should know living in CO. By properly equipped with studded snow tires and weight (1000lb) in the bed forward of the rear axle. I run studded Nokian Tyres HakkaPELIITTA LT3 . Run them for years and they really tame a dully in snow and the Illinois packed ice roadways - lived in Peoria for 22+ years

Now as brand choice - have you even looked at a Ford F450 6.7 or HO 6.7 with its tight turning radius? It can make a huge difference.

 

[powerscol]

A DRW can be much safer than a SRW. One - the wider stance is more stable in winds and uneaven loads and also with semi's passing. Breaking is better with more tire contact with the road. In addition if a rear tire blowes the second one will pick up the load. With a SRW your up the creek in handling. I have had both situations happen in my life, and with that weight the dually is a must. The OP needs a dally with max GVW capacity and a rear sway bar.

 

[Tom Traveler]

I am always surprised at the fervor of the SRW cult on this forum.

At our last RV park, I saw a 5th wheel hooked up to a semi-tractor. I wish I had taken a picture. Now that is low risk tolerance. I suspect he was an independent trucker and saw no need to buy another truck.

We all balance risk and cost (monetary or other) in many aspects of our life. Some people buy cheaper tires to save money. Some people drive faster to save time. Sometimes I drive 72 mph on good pavement with 75+ speed limits and light traffic. I am less safe than someone driving 65 mph.

The comment about not being concerned about a front axle blowout doesn't seem to apply. I didn't think they made DFW trucks so we drive what is available.

I'm always curious about "breakpoints". A SRW is good, and as safe as, a DRW up to 4,000 lbs. (for example). But over that, you should get a DRW. Why? Is it safer than a SRW for the higher weight? If not, why would one ever buy a DRW? If it is safer than a SRW for the higher weight, they why wouldn't it be safer for weights under 4,000 lbs, if one was inclined to trade money for safety.

DRW trucks are inherently safer because of physics (let's leave ice and snow driving out of this for now). They have more rubber on the road and the tipping or rocking point is further from the center of gravity. That doesn't mean that everyone should drive one. The chances of needing that extra safety are very, very small and there are convenience and cost downsides of a DRW. In the end, if one is near the breakpoint (rated payload limit), one will be making a risk tolerance decision. Unless taken to an extreme, that doesn't make them a "bad" person.

 

[powerscol]

Actually a cult is defined as "A system of religious veneration and devotion directed toward a particular figure or object.". It fits the bill perfectly.

Without even knowing it you exhibited the cult behavior. You downplayed the disadvantages while focusing on the benefits. Are you concerned about the poor traction in snow and mud? Never go to RV parks or boondock where that is an issue? No concern about the extra maintenance costs? Enjoying putting air in the inside tires? Uneven tire wear on the back tires? Difficulty if you use the truck for sightseeing, especially in cities? Had to drive that DRW truck over Going to the Sun Road in Glacier and wished you had a SRW truck? Couldn't fit into a parking garage so you literally had no place to park in Newport RI? All those are downsides for real world users.

In the first response to the OP, Calbar provided sound fact-based advice based on his real world experience. Kudos for a great post. Xrated provided good general guidance. The forum needs more of that. Not stock answers without facts or pros/cons.

OK Dually down sides. 6 tires to buy and rotate. I bought my tires from a dealer that offered free rotation, even for a dually where they will mount and remount as the front rims are different from the back. Was not a problem for me ever.

Size - yes you need to be careful picking a parking spot, and over time you learn the dimensions.

Fuel mileage - mileage was a little worse than my current SRW (only towing an 8K trailer now) that was due to gearing. A dually plus is you can get the lower gearing for the big trailer which is less wear on the trans. Many SRW can not be gotten with 4:10 or 4:30 gearing and for an 18K trailer that is a lot more stress on the trans

More surface area to wash

Price - can be a bit more, but not always true.

Weight - dully weighs more, but that extra weight is a plus in my book as stronger components are used.

Now am I pro dually for everyone - no. If your under 12K gvw you don't need one. Over 16K GVW I say a must. At 18K I say an F450 is needed. The big plus for the F450 is the turning radius - best of any brand truck. It is also built like a tank. Don't let the CCC and GVW rating fool you as it is de-rated for licensing purposes.

 

[BobKilmer]

I am always surprised at the fervor of the SRW cult on this forum.

At our last RV park, I saw a 5th wheel hooked up to a semi-tractor. I wish I had taken a picture. Now that is low risk tolerance. I suspect he was an independent trucker and saw no need to buy another truck.

We all balance risk and cost (monetary or other) in many aspects of our life. Some people buy cheaper tires to save money. Some people drive faster to save time. Sometimes I drive 72 mph on good pavement with 75+ speed limits and light traffic. I am less safe than someone driving 65 mph.

The comment about not being concerned about a front axle blowout doesn't seem to apply. I didn't think they made DFW trucks so we drive what is available.

I'm always curious about "breakpoints". A SRW is good, and as safe as, a DRW up to 4,000 lbs. (for example). But over that, you should get a DRW. Why? Is it safer than a SRW for the higher weight? If not, why would one ever buy a DRW? If it is safer than a SRW for the higher weight, they why wouldn't it be safer for weights under 4,000 lbs, if one was inclined to trade money for safety.

DRW trucks are inherently safer because of physics (let's leave ice and snow driving out of this for now). They have more rubber on the road and the tipping or rocking point is further from the center of gravity. That doesn't mean that everyone should drive one. The chances of needing that extra safety are very, very small and there are convenience and cost downsides of a DRW. In the end, if one is near the breakpoint (rated payload limit), one will be making a risk tolerance decision. Unless taken to an extreme, that doesn't make them a "bad" person.

I started by calling the DRW group "a cult". You responded by saying there is a "SRW Cult". No fair taking my term.

As for breakpoints, I agree they exist. They are the GVWR, GCWR, GAWR,....Those limits are defined by engineers and tests. Not by the feelings of whether two wheels are better than one on each side of the rear axle. Those breakpoints for SRW move higher every year. And those breakpoints are exactly what should be used for making a recommendation on a tow vehicle. Not emotions.

As for the single front tire, it is a perfectly valid point that DRW owners don't like. Every nightmare scenario used to rationalize a DRW vehicle focuses on a rear tire blowout. And yet there are two single front tires. So the logic of needing two rear tires for safety looks a little weak in light of that.

As for the physics of the DRW design, the extra width for stability is only a factor if the truck is at the point where it is physically going to be tipped over. It has zero impact anywhere else. To see that all you need to do is look at the load paths from the hitch and frame down to the axle. They are the same for each design.

 

[BobKilmer]

A DRW can be much safer than a SRW. One - the wider stance is more stable in winds and uneaven loads and also with semi's passing. Breaking is better with more tire contact with the road. In addition if a rear tire blowes the second one will pick up the load. With a SRW your up the creek in handling. I have had both situations happen in my life, and with that weight the dually is a must. The OP needs a dally with max GVW capacity and a rear sway bar.

I am glad to stir the pot with this comment

Here is a challenge for all DRW owners. Go look at the how suspension transfers the loads from the hitch and frame down to the axle. Then go look at the same model SRW truck. I am willing to bet that the load transfer path down to the axles is the same width as the DRW truck. If it isn't the same, then each manufacturer would need a unique dually frame and a non-dually frame. This width is the limiting factor for stability for the truck, not the width at the outside edge of tires. The only point where the extra width becomes a benefit is when the truck is at the point of being tipped off the ground. At that point I don't think the extra 10% of track width for a dually is important.

For braking, I have never seen a truck test where a DRW truck had better braking than a SRW truck.

 

[BobKilmer]

Let me stir the pot some more. I have been towing RVs for well over 30 years. I have towed with both SRW and DRW. Until my present Momentum, all of my previous TTs could have been towed with SRWs. My first TV was a SRW. I am now on my third dually, and I do not see myself ever going back to a SRW. There have been a few incidences when I was sure happy to have the safety cushion that a dually provides. When one of those"moments" occurs, one has to handle it with the truck you have There will be no do over. All of the listed downsides to DRW are true, but they are not insurmountable problems.

What it all boils down to is just how safe do you want to be? Everyone has a different tolerance for risk, so their answers wil be different because of it.
There is just one aspect of this converstion that is not debatable.
A dually is a better/safer towing platform for a TV. Many of those that refuse to acknowledge this fact are just trying to justify their choice in TVs

I have no need to justify my TV. The engineers at Ford, Grand Design, and SAE did that for me. They wrote the specs, did the testing, and developed the products. I now use what they designed and built in the proper manner, within spec.

You can state that something is not debatable, but that doesn't make it so. If you have facts that say a dually is safer, I would love to see them. Some safety analysis that says adding two extra tires to the system (RV and TV) makes it measurably safer without introducing more failure modes (extra tires to fail). For me, I see two extremely low probability events (blowout and catastrophic failure) that don't make any difference in light of all the other failure modes.

 

[huntindog]

I am glad to stir the pot with this comment

Here is a challenge for all DRW owners. Go look at the how suspension transfers the loads from the hitch and frame down to the axle. Then go look at the same model SRW truck. I am willing to bet that the load transfer path down to the axles is the same width as the DRW truck. If it isn't the same, then each manufacturer would need a unique dually frame and a non-dually frame. This width is the limiting factor for stability for the truck, not the width at the outside edge of tires. The only point where the extra width becomes a benefit is when the truck is at the point of being tipped off the ground. At that point I don't think the extra 10% of track width for a dually is important.

For braking, I have never seen a truck test where a DRW truck had better braking than a SRW truck.

Likely because I have never seen a braking test that pitted DRW against SRW.

It is a simple concept. More rubber on the ground makes for more traction. More traction means better braking....

 

[BobKilmer]

Likely because I have never seen a braking test that pitted DRW against SRW.

It is a simple concept. More rubber on the ground makes for more traction. More traction means better braking....

More ground contact on the tires that do the least amount of braking. The vast majority of the braking on any vehicle is done by the front tires due to weight transfer. And on a vehicle that weighs more due to the extra tires, bigger axle, body panels,....

A few years ago Motor Trend did testing that included both a SRW and a DRW RAM for their truck of the year. They never commented or posted on a difference in braking. I asked them for the data but didn't get a response.

Edit: Here is a link where the RAM 2500 SRW and RAM 3500 DRW are tested. The SRW truck had a five foot shorter stopping distance. Different tires and different weight vehicles, but it shows being DRW doesn't simply mean better stopping.

https://www.motortrend.com/news/ram...2020 Truck,Year contenders and finalists HERE.

 

[huntindog]

More ground contact on the tires that do the least amount of braking. The vast majority of the braking on any vehicle is done by the front tires due to weight transfer. And on a vehicle that weighs more due to the extra tires, bigger axle, body panels,....

A few years ago Motor Trend did testing that included both a SRW and a DRW RAM for their truck of the year. They never commented or posted on a difference in braking. I asked them for the data but didn't get a response.

Edit: Here is a link where the RAM 2500 SRW and RAM 3500 DRW are tested. The SRW truck had a five foot shorter stopping distance. Different tires and different weight vehicles, but it shows being DRW doesn't simply mean better stopping.

https://www.motortrend.com/news/ram...2020 Truck,Year contenders and finalists HERE.

I thought we were debating towing perfomance? Your braking example goes out the window with a trailer in tow.
when braking hard the pin weight increases dramatically pushing the rear tires into the road.

 

[BobKilmer]

I thought we were debating towing perfomance? Your braking example goes out the window with a trailer in tow.
when braking hard the pin weight increases dramatically pushing the rear tires into the road.

I didn't raise the difference in braking of SRW vs DRW. You did. I believe there is no real difference between the two.

I doubt the braking is going to behave as you described. There isn't really a weight transfer happening during braking, it is accelerations changing the forces on the vehicles. Any force from the RV deceleration is going to be forward, not down, and this will still load the front suspension of the TV, not the rear suspension.

 

[Tony_in_AZ]

A photo of the frame sticker on my 2021 F350 4x4 dually long bed truck. I thought it was interesting.

 

[powerscol]

I didn't raise the difference in braking of SRW vs DRW. You did. I believe there is no real difference between the two.

I doubt the braking is going to behave as you described. There isn't really a weight transfer happening during braking, it is accelerations changing the forces on the vehicles. Any force from the RV deceleration is going to be forward, not down, and this will still load the front suspension of the TV, not the rear suspension.

It appears you have never studied engineering or taken a dynamics class. [MENTION=12888]huntindog[/MENTION] is correct especially for a 5th wheel. The king pin will rotate down increasing the load and depending on the hitch location effect front steering geometry. Yes it also shifts the weight forward as well. Unfortunately the trailer front axle lifts at the same time which is the result of the load shift on the equalizer. Lots of videos on this ( check MorRyde web page) showing the front wheel lockup.

Now as to the path of the load, yes the load on a SRW and DRW passes through the springs to the axle. The axle on the DRW spreads the load out wider and the springs are stiffer. Also I believe you will find the frame on a dually is slightly different than the SRW with different stuffier springs (this changes the load transfer weight) and mounting points, slightly outboard from the SRW due to the Dana 80 axle over the smaller Sterling axle. Other brands may be different. This is a good topic to search.

Now of note, I don't think the OP has been back to comment on anything since their first post I still believe he needs more truck

Also there was a post of folks towing a 150 series with a dually. I did that for a while after downsizing my trailer. I did not need a big unit anymore, and used the dually as I normally wood. Also some folk tow other trailers for work etc. Some like the extra stability of a dually too.

And there is nothing wrong with having too much truck. I have been an engineer too long to gamble on the safety of my family, to save a penny on a smaller truck.

Before I ordered my new truck I even considered a F450 for the turning radius and possible future trailer. I like to stay away from glamping (full hookups) and like the state and local parks and even the Nation Parks, all of which have average max unit length of about 35' and have tight sites, many unchanged fir over 40 years, and yes I have been towing various RV's that long or longer.

 

[BobKilmer]

It appears you have never studied engineering or taken a dynamics class. [MENTION=12888]huntindog[/MENTION] is correct especially for a 5th wheel. The king pin will rotate down increasing the load and depending on the hitch location effect front steering geometry. Yes it also shifts the weight forward as well. Unfortunately the trailer front axle lifts at the same time which is the result of the load shift on the equalizer. Lots of videos on this ( check MorRyde web page) showing the front wheel lockup.

Now as to the path of the load, yes the load on a SRW and DRW passes through the springs to the axle. The axle on the DRW spreads the load out wider and the springs are stiffer. Also I believe you will find the frame on a dually is slightly different than the SRW with different stuffier springs (this changes the load transfer weight) and mounting points, slightly outboard from the SRW due to the Dana 80 axle over the smaller Sterling axle. Other brands may be different. This is a good topic to search.

Now of note, I don't think the OP has been back to comment on anything since their first post I still believe he needs more truck

Also there was a post of folks towing a 150 series with a dually. I did that for a while after downsizing my trailer. I did not need a big unit anymore, and used the dually as I normally wood. Also some folk tow other trailers for work etc. Some like the extra stability of a dually too.

And there is nothing wrong with having too much truck. I have been an engineer too long to gamble on the safety of my family, to save a penny on a smaller truck.

Before I ordered my new truck I even considered a F450 for the turning radius and possible future trailer. I like to stay away from glamping (full hookups) and like the state and local parks and even the Nation Parks, all of which have average max unit length of about 35' and have tight sites, many unchanged fir over 40 years, and yes I have been towing various RV's that long or longer.

You really should check your facts before making personal comments. I have degrees in Math, Physics, and Engineering. And 40 years of engineering experience designing and building complex, real world, aircraft and systems. I will match my engineering skills and experience against anyone. If you would like I will exchange resumes.

That experience, and the multiple dynamics classes I HAVE taken, are why I can say that huntindog is wrong. In fact, if you look at your comments, they indicate exactly what I said will happen. The load will transfer primarily to the front axles of the truck. If you draw a static and dynamic load diagram you will see that.

As for the wider body, I guess you didn't see the post just before yours. The F-350 Dually frame is the same as the F-350 SRW and F-250 SRW frame. The frame load paths are the same. Stiffer springs don't change the load path or the actual weight transferred.

For the load paths, again draw a static and dynamic load diagram. The torque and weight from the hitch is following a common load path on both the SRW and DRW path down to the axle. For there to be a difference in SRW vs DRW, there would have to be one of the following happening:
1) The axle is flexing to the point it can be felt in the truck. Doubtful any axle could take this much flex.
2) The tire tread is compressing to the point of being felt in the truck. Extremely doubtful. I would expect this to be accompanied by a squealing noise similar to cornering too hard.
Unless those are happening weight to the axle is the same as weight to the ground. Being wider doesn't help until there is enough force to try to lift a tire. Then being wider helps.

The one valid point you make is the difference in spring weights. That is the one difference that matters under normal conditions. I believe that the reported improvement for towing performance that most people talk about is due to this factor. I realized that long ago and I offset the added load of towing with my air springs. It doesn't change my ratings, but it allows me to use the full towing capability without any concerns about hitting my overload springs.

You are also correct about there not being anything wrong with having too much truck. But there is something wrong about confusing preference versus requirements, or making subtle jabs about safety wrapped in moneysaving comments.

 

[powerscol]

You really should check your facts before making personal comments. I have degrees in Math, Physics, and Engineering. And 40 years of engineering experience designing and building complex, real world, aircraft and systems. I will match my engineering skills and experience against anyone. If you would like I will exchange resumes.

That experience, and the multiple dynamics classes I HAVE taken, are why I can say that hutindog is wrong. In fact, if you look at your comments, they indicate exactly what I said will happen. The load will transfer primarily to the front axles of the truck. If you draw a static and dynamic load diagram you will see that.

As for the wider body, I guess you didn't see the post just before yours. The F-350 Dually frame is the same as the F-350 SRW and F-250 SRW frame. The frame load paths are the same. Stiffer springs don't change the load path or the actual weight transferred.

For the load paths, again draw a static and dynamic load diagram. The torque and weight from the hitch is following a common load path on both the SRW and DRW path down to the axle. For there to be a difference in SRW vs DRW, there would have to be one of the following happening:
1) The axle is flexing to the point it can be felt in the truck. Doubtful any axle could take this much flex.
2) The tire tread is compressing to the point of being felt in the truck. Extremely doubtful. I would expect this to be accompanied by a squealing noise similar to cornering too hard.
Unless those are happening weight to the axle is the same as weight to the ground. Being wider doesn't help until there is enough force to try to lift a tire. Then being wider helps.

The one valid point you make is the difference in spring weights. That is the one difference that matters under normal conditions. The reported improvement on towing performance is due to this factor. I realized that long ago and I offset the added load of towing with my air springs. It doesn't change my ratings, but it allows me to use the full towing capability without any concerns about hitting my overload springs.

You are also correct about there not being anything wrong with having too much truck. But there is something wrong about confusing preference versus requirements, or making subtle jabs about safety wrapped in moneysaving comments.

Not going down the rabbit hole

Safe travels

 

[huntindog]

I didn't raise the difference in braking of SRW vs DRW. You did. I believe there is no real difference between the two.

I doubt the braking is going to behave as you described. There isn't really a weight transfer happening during braking, it is accelerations changing the forces on the vehicles. Any force from the RV deceleration is going to be forward, not down, and this will still load the front suspension of the TV, not the rear suspension.

Not if your trailer brakes are working as they should be.

 

[Scott'n'Wendy]

Properly set up brakes will cause some but not huge upward/downward, forward/backward forces on the KP. Opinion...no data to back that up...lol
Typically, 70% of the braking of the TV is done by the front brakes. If there is extra pressure on the KP either upward or downward, it will change the point in which the anti-lock moderates the pressure in a panic stop.
IMO, the safety discussion is just personal. If you are towing within the rated payload of your TV, or the one you are about to buy, you are lots safe. How you drive is probably a bigger factor in safety..lol

 

[Calbar]

Properly set up brakes will cause some but not huge upward/downward, forward/backward forces on the KP. Opinion...no data to back that up...lol
Typically, 70% of the braking of the TV is done by the front brakes. If there is extra pressure on the KP either upward or downward, it will change the point in which the anti-lock moderates the pressure in a panic stop.
IMO, the safety discussion is just personal. If you are towing within the rated payload of your TV, or the one you are about to buy, you are lots safe. How you drive is probably a bigger factor in safety..lol

Very well said.

Rob

 

[LMagelitz]

After not seeing this for a couple of days, all I can say is, “the poor OP got more than he bargained for.” Maybe the OP should find a couple buddies, one with an SRW and one with DRW and decide for himself. That would be better than trying to gather anything useful from a bickering tirade between the “I have been driving for 150 years and have 42 doctoral degrees” from the SRW-only OR the DRW-only crowd.

When deciding between two important things, I’ll usually weight the opinions of those that have had each “thing” more than those that have only had one of the “things.” That is where the “experience” piece of the “tow experience” comes from.

Don’t bother flaming this response, cause I’m out. Geez…..

 

[Second Chance]

Thread closed.

Rob