Notes from a first time RVer on towing capacity, trucks and fifth wheels

DCGD2023

New Member
Joined
Dec 17, 2022
Messages
6
Cheers everyone. We are soon-to-be first time RVers who have just spent time diving into the research on towing requirements for trucks and fifth wheels. We just bought our truck - an F350 DRW - and are aiming to buy a fifth wheel in the spring. I thought it might be helpful to summarize a few of the things we've learned recently in case it can help others.

A couple of caveats. We have not applied these rules in practice yet, so this is just me conveying information based on research we've done, not experiences we've had. In addition, I may not be using exactly the right weight terms in each instance here. On either front, I'm happy to have any long-timers correct me. :)

That said, here's what we've learned:

First, very few RV or truck salespeople truly understand weight and towing figures. If they do, they don't share. When talking to them, keep in mind that their job is to make a sale. Our conclusion is that most of the ones we've met are honest, but they don't really know their stuff. They know the basics, but when you start getting into the weeds you won't get specific answers. It also appears fairly common that RVers push or exceed the limits on their towing capacity and get away with it, leading many dealers to tell you that "people do it all the time." One salesman told us that we could easily tow a GD 2930 Solitude with an F350 SRW, saying that if it were him he would "do it all day long," but when we ran the numbers we realized that with a sliding hitch, two passengers and two dogs, we would be at 105% of the maximum truck payload weight, even without any bags or guests in the truck. In light of that, you can't really rely on what you are being told. You must do your own research.

Second, doing your own research doesn't mean you'll get clear answers. You'll get a wide range of answers and opinions, oftentimes totally contradictory. This is a situation where you need to get all the information, then make your own decision. As Lee Iacocca once said, "think for yourself." That is necessarily going to include making your own risk assessment of what kinds of safety margins you prefer.

Third, before diving into the requirements on particular trucks and fifth wheels, learn about the 80/20 rule. This is a safety rule of thumb which basically says that you should not exceed 80% of the various weight limits on your towing vehicle. Many dealers will tell you that you don't need to apply the rule, that many people ignore it and tow their fifth wheels just fine, etc. We have found that the best and most helpful posts on the forums posted by experienced RV owners advise that you should follow the rule. There are many reasons why it makes sense: individual vehicles may vary from factory weight ratings, the manner in which you load the vehicles can affect the weight ratios, the driving conditions which you experience may vary from the straight and narrow roads which oftentimes underlie the factory's weight calculations, your two largest friends may want to pile in the truck with you and affect the payload, etc. Based on the best advice we've received, you're going to want a cushion. Doing that not only helps with actual safety, it helps with peace of mind, which is a major reason why we want to go RVing in the first place.

Fourth, when doing your planning don't make the mistake of focusing on just a truck's towing capacity at the expense of hitch weight / pin weight. The towing capacity of many newer 350 or 3500 SRW trucks is quite high. For example, a 2022 F350 SRW may be able to tow 19,000 pounds. Applying the 80/20 rule to that figure, you could safely tow a fifth wheel with a full (i.e., GVWR) weight of 15,200 pounds. But if you don't also pay attention to the payload figure, you may buy a fifth wheel that you can tow but that may make the overall weight of your truck too high when you add other parts of the payload like passengers, dogs, bags, weight of the tow hitch installed in the bed, etc.

So when buying a truck, always look at the payload sticker that is on the truck (ours was on the door jam). For Ford trucks, it says that the maximum weight of passengers and cargo is X pounds. We were told that, in applying this figure, you don't take into account the weight of the fuel in the truck - that is already factored in. They are really talking about the weight of things you put into the fully-fueled truck, including passengers, dogs, bags, the weight of the hitch, anything else you put in the bed, etc. When deciding on a fifth wheel, the basic formula that you need to do is to take the payload figure on the sticker (for example 3,400 pounds), subtract the likely weight of passengers and cargo that you put in the truck (for example 1,000 pounds), and then the remaining number gives you the weight that the truck can safely handle from the weight of the fifth wheel sitting on your hitch in the bed of the truck (in this case, 2,400 pounds). There are other weights such as axle rating that you also need to review, but it seems to us that those numbers are pretty safely met if you are within the limits on towing capacity and hitch weight.

Fifth, when doing the calculation of hitch weight from the fifth wheel, you will get widely varying figures on what percentage of the fifth wheel's weight will be transferred to the truck. The typical ratios that we saw ran from 15-25%. It appears that, in recent years, the percentage has dropped as fifth wheel manufacturers have revised their manufacturing. For most Solitudes, it looked like the dry weight ratio (i.e., as the empty vehicle comes out of the factory) is roughly 20%. But the percentage that is actually achieved in any given circumstance, which depends on what you put in the fifth wheel and where you put it, makes a huge difference. For example, if you have a fifth wheel weighing 15,000 pounds fully loaded, if you load it in such a manner that the weight ratio going to the truck is 15%, then 2,250 pounds is being placed on the bed of your truck. If, however, you load it so that the ratio is 25%, 3,750 pounds is being applied. That may not make a huge difference if you have a dually / DRW truck, which oftentimes have payload capacities in the 5,500 range, but it can make a huge difference if you have a SRW. Even at 15% you may be close to or exceeding the payload capacity of a SRW truck. If you load the fifth wheel in such a manner that you are at 25%, you will likely be way over the limit.

When buying a truck and a fifth wheel, you also have to recognize that you cannot accurately know in advance what ratio would be applied until you actually get out there and start using your fifth wheel. Before you buy it, you're not allowed to take the fifth wheel off the dealer's lot to go to a weighing station and test it with your truck. So you have to plan ahead. The most helpful posts that we saw from RV owners said to make sure that your towing vehicle could handle the weight of a fully loaded fifth wheel with a 25% weight ratio on the hitch. That's obviously a conservative approach, but we decided that it made sense for us, and hence we've gone with a dually rather than an SRW in order to be able to tow fifth wheels the size of a Solitude.

Sixth, there is virtually no information out there on the question of whether you should apply the 80/20 rule to the truck's payload weight in addition to towing capacity. Most dealers told us that no one had ever asked the question, or that the 80/20 rule only applies to towing capacity but not hitch weight. There does not appear to be a clear answer. Since the 80/20 rule is just a common sense rule of thumb to increase your safety margin, we've decided to apply it to hitch weight as well as towing capacity. We don't want to be towing our fully loaded fifth wheel up the Rocky Mountains in high winds with friends or family in the back seat and then find out we should have been more conservative.

Seventh, when buying a fifth wheel make sure that you don't rely just on the factory ratings for things like UVW (unloaded vehicle weight); look at the sticker that actually appears on that particular vehicle. When looking at one fifth wheel, we found that the dry weight for that particular unit was a few hundred pounds over what was on the Grand Design website as the standard UVW. You need to look at the number that applies to your particular unit when starting your calculations.

Eighth, there are lots of posts out there from RVers who said that they made the mistake of trying to drive a large fifth wheel with an SRW, only to realize after the fact that they needed a DRW. We've taken that to hear.

That summarizes what we've learned so far. As noted above, since we're new to this take these comments with a grain of salt.

We're looking forward to meeting some of you when we get out on the road! :)
 
Looks like you have done your research. A couple of comments.

80/20 rule not talked about much on this forum.
Yes many people run their rigs overloaded.
Yes many sales people don’t know what they are talking about.
You probably will never see a non-toy hauler fifth wheel at 15% pin weight, they come from the factory with more pine weight then that. Adding weight to a toy hauler garage will reduce pin weight.
Most Grand Design fifth wheels have little storage room in the back so loading options are limited. Most cargo weight goes in front of the axel and adds weight to the pin.
Yes advertised UVW is usually a couple hundred pounds less than actual weight depending on options.

Since you have not purchased a fifth wheel and into research, make sure you look at the maximum weight of cargo you can put in the fifth wheel. GVWR - UVW. My 337RLS is around 3,000 pounds. Some models can only carry 2,000 or less.
 
Cheers everyone. We are soon-to-be first time RVers who have just spent time diving into the research on towing requirements for trucks and fifth wheels. We just bought our truck - an F350 DRW - and are aiming to buy a fifth wheel in the spring. I thought it might be helpful to summarize a few of the things we've learned recently in case it can help others.

A couple of caveats. We have not applied these rules in practice yet, so this is just me conveying information based on research we've done, not experiences we've had. In addition, I may not be using exactly the right weight terms in each instance here. On either front, I'm happy to have any long-timers correct me. :)

That said, here's what we've learned:

First, very few RV or truck salespeople truly understand weight and towing figures. If they do, they don't share. When talking to them, keep in mind that their job is to make a sale. Our conclusion is that most of the ones we've met are honest, but they don't really know their stuff. They know the basics, but when you start getting into the weeds you won't get specific answers. It also appears fairly common that RVers push or exceed the limits on their towing capacity and get away with it, leading many dealers to tell you that "people do it all the time." One salesman told us that we could easily tow a GD 2930 Solitude with an F350 SRW, saying that if it were him he would "do it all day long," but when we ran the numbers we realized that with a sliding hitch, two passengers and two dogs, we would be at 105% of the maximum truck payload weight, even without any bags or guests in the truck. In light of that, you can't really rely on what you are being told. You must do your own research.

Second, doing your own research doesn't mean you'll get clear answers. You'll get a wide range of answers and opinions, oftentimes totally contradictory. This is a situation where you need to get all the information, then make your own decision. As Lee Iacocca once said, "think for yourself." That is necessarily going to include making your own risk assessment of what kinds of safety margins you prefer.

Third, before diving into the requirements on particular trucks and fifth wheels, learn about the 80/20 rule. This is a safety rule of thumb which basically says that you should not exceed 80% of the various weight limits on your towing vehicle. Many dealers will tell you that you don't need to apply the rule, that many people ignore it and tow their fifth wheels just fine, etc. We have found that the best and most helpful posts on the forums posted by experienced RV owners advise that you should follow the rule. There are many reasons why it makes sense: individual vehicles may vary from factory weight ratings, the manner in which you load the vehicles can affect the weight ratios, the driving conditions which you experience may vary from the straight and narrow roads which oftentimes underlie the factory's weight calculations, your two largest friends may want to pile in the truck with you and affect the payload, etc. Based on the best advice we've received, you're going to want a cushion. Doing that not only helps with actual safety, it helps with peace of mind, which is a major reason why we want to go RVing in the first place.

Fourth, when doing your planning don't make the mistake of focusing on just a truck's towing capacity at the expense of hitch weight / pin weight. The towing capacity of many newer 350 or 3500 SRW trucks is quite high. For example, a 2022 F350 SRW may be able to tow 19,000 pounds. Applying the 80/20 rule to that figure, you could safely tow a fifth wheel with a full (i.e., GVWR) weight of 15,200 pounds. But if you don't also pay attention to the payload figure, you may buy a fifth wheel that you can tow but that may make the overall weight of your truck too high when you add other parts of the payload like passengers, dogs, bags, weight of the tow hitch installed in the bed, etc.

So when buying a truck, always look at the payload sticker that is on the truck (ours was on the door jam). For Ford trucks, it says that the maximum weight of passengers and cargo is X pounds. We were told that, in applying this figure, you don't take into account the weight of the fuel in the truck - that is already factored in. They are really talking about the weight of things you put into the fully-fueled truck, including passengers, dogs, bags, the weight of the hitch, anything else you put in the bed, etc. When deciding on a fifth wheel, the basic formula that you need to do is to take the payload figure on the sticker (for example 3,400 pounds), subtract the likely weight of passengers and cargo that you put in the truck (for example 1,000 pounds), and then the remaining number gives you the weight that the truck can safely handle from the weight of the fifth wheel sitting on your hitch in the bed of the truck (in this case, 2,400 pounds). There are other weights such as axle rating that you also need to review, but it seems to us that those numbers are pretty safely met if you are within the limits on towing capacity and hitch weight.

Fifth, when doing the calculation of hitch weight from the fifth wheel, you will get widely varying figures on what percentage of the fifth wheel's weight will be transferred to the truck. The typical ratios that we saw ran from 15-25%. It appears that, in recent years, the percentage has dropped as fifth wheel manufacturers have revised their manufacturing. For most Solitudes, it looked like the dry weight ratio (i.e., as the empty vehicle comes out of the factory) is roughly 20%. But the percentage that is actually achieved in any given circumstance, which depends on what you put in the fifth wheel and where you put it, makes a huge difference. For example, if you have a fifth wheel weighing 15,000 pounds fully loaded, if you load it in such a manner that the weight ratio going to the truck is 15%, then 2,250 pounds is being placed on the bed of your truck. If, however, you load it so that the ratio is 25%, 3,750 pounds is being applied. That may not make a huge difference if you have a dually / DRW truck, which oftentimes have payload capacities in the 5,500 range, but it can make a huge difference if you have a SRW. Even at 15% you may be close to or exceeding the payload capacity of a SRW truck. If you load the fifth wheel in such a manner that you are at 25%, you will likely be way over the limit.

When buying a truck and a fifth wheel, you also have to recognize that you cannot accurately know in advance what ratio would be applied until you actually get out there and start using your fifth wheel. Before you buy it, you're not allowed to take the fifth wheel off the dealer's lot to go to a weighing station and test it with your truck. So you have to plan ahead. The most helpful posts that we saw from RV owners said to make sure that your towing vehicle could handle the weight of a fully loaded fifth wheel with a 25% weight ratio on the hitch. That's obviously a conservative approach, but we decided that it made sense for us, and hence we've gone with a dually rather than an SRW in order to be able to tow fifth wheels the size of a Solitude.

Sixth, there is virtually no information out there on the question of whether you should apply the 80/20 rule to the truck's payload weight in addition to towing capacity. Most dealers told us that no one had ever asked the question, or that the 80/20 rule only applies to towing capacity but not hitch weight. There does not appear to be a clear answer. Since the 80/20 rule is just a common sense rule of thumb to increase your safety margin, we've decided to apply it to hitch weight as well as towing capacity. We don't want to be towing our fully loaded fifth wheel up the Rocky Mountains in high winds with friends or family in the back seat and then find out we should have been more conservative.

Seventh, when buying a fifth wheel make sure that you don't rely just on the factory ratings for things like UVW (unloaded vehicle weight); look at the sticker that actually appears on that particular vehicle. When looking at one fifth wheel, we found that the dry weight for that particular unit was a few hundred pounds over what was on the Grand Design website as the standard UVW. You need to look at the number that applies to your particular unit when starting your calculations.

Eighth, there are lots of posts out there from RVers who said that they made the mistake of trying to drive a large fifth wheel with an SRW, only to realize after the fact that they needed a DRW. We've taken that to hear.

That summarizes what we've learned so far. As noted above, since we're new to this take these comments with a grain of salt.

We're looking forward to meeting some of you when we get out on the road! :)

Absolutely! You are starting out with the right frame of mind. One other thing I would tell people to pay attention to, not related to towing, is the CCC of the 5th wheel, like a Solitude. By the time the factory adds in all the dodads, options, the CCC of the trailer could be less than 2000#. That doesn't leave much capacity for you to load all your stuff. We have met a lot of owners that focused on towing and tow vehicles, but then found out they overloaded the RV because they didn't have enough CCC. If possible get the axle upgrade to 8000#, that will get your RV CCC back up where most owners need it.

See our signature line for our rig and tow vehicle. We run at @ 21% of the trailers GVWR, as actual pin weight.
 
Third, before diving into the requirements on particular trucks and fifth wheels, learn about the 80/20 rule. This is a safety rule of thumb which basically says that you should not exceed 80% of the various weight limits on your towing vehicle. Many dealers will tell you that you don't need to apply the rule, that many people ignore it and tow their fifth wheels just fine, etc. We have found that the best and most helpful posts on the forums posted by experienced RV owners advise that you should follow the rule. There are many reasons why it makes sense: individual vehicles may vary from factory weight ratings, the manner in which you load the vehicles can affect the weight ratios, the driving conditions which you experience may vary from the straight and narrow roads which oftentimes underlie the factory's weight calculations, your two largest friends may want to pile in the truck with you and affect the payload, etc. Based on the best advice we've received, you're going to want a cushion. Doing that not only helps with actual safety, it helps with peace of mind, which is a major reason why we want to go RVing in the first place.

Sixth, there is virtually no information out there on the question of whether you should apply the 80/20 rule to the truck's payload weight in addition to towing capacity. Most dealers told us that no one had ever asked the question, or that the 80/20 rule only applies to towing capacity but not hitch weight. There does not appear to be a clear answer. Since the 80/20 rule is just a common sense rule of thumb to increase your safety margin, we've decided to apply it to hitch weight as well as towing capacity. We don't want to be towing our fully loaded fifth wheel up the Rocky Mountains in high winds with friends or family in the back seat and then find out we should have been more conservative.

I am not in agreement with the 80/20 "rule". If you are saying that the truck can not handle the weight it was designed for, or at the max weight, its life is shortened, than I would like to see any documented evidence of that. Take it a step further, the heavy duty trucks are all designed with the rear 2-3" higher than the front, because the manufacturer expects you to put a bunch of weight in it causing the rear to sag. Also, the heavier the truck (within limits), the better it will handle the trailer. No one designs a truck that will prematurely fail at its designed max weight, a safety margin is built in, not saying one should depend on that, or what that percentage is. If you are saying that an inexperienced person should follow that rule until they get some experience, and comfort, I actually think that is a good thing. If you are saying that one should use that rule because they don't have an idea of what they weigh, or that bubba may join them, then that person has a different problem. As has been preached here, load your truck up, and hit the CAT scale, than you know the real weight that you have, not what the sticker said when the truck left the factory.

As far as that rule to apply to the trailer, most do not pay attention to it. Trailers are a mess in quality, and build. Although I would have no problems running my trailer at its max weight, I am solo, and my current bike is around 540 lbs., on the last CAT scale my trailer is about 83% of its max weight. That still hasn't stopped the springs (second set) from going flat.

Thank you for your thought out post, it will help a new person, giving them more information to make a good decision.
 
My guess is from an engineering standpoint there's already a cushion built in.
Maybe the trucks tow rating already has the 80/20 rule built in.
Regardless having the right truck for the job is the best rule.
 
If people actually abided by the 80/20 rule, there would be a lot fewer 5th wheels towed by 3/4 tons, and none pulled by 1/2 tons. And AFATG, probably not that many pulled by 1-ton single rear wheels. And a paucity of 40+ ft. trailers pulled by any pickup truck. :) It sounds good, but just doesn't seem to be at all practical. And I never even heard of it until a couple months ago. But only been towing about 20 years. :)
 
I'm in agreement with others on the so-called "80/20 rule." Old-timers used to pay homage to that concept "back in the day." Perhaps manufacturer's ratings were arrived at differently back then, but any modern truck is capable of handling weights up to (and usually slightly beyond) the ratings on the door sticker (not the general specifications guidelines found on the manufacturers' web sites). Continuing to follow this so-called rule implies that the automotive engineers - many with PhDs in engineering - don't know what they're doing. That said, many of us like to have some wiggle room. I towed our previous Reflection 337RLS with a single-rear-wheel truck. At 3,060 lbs. on the pin, the combo was within specs... but I wasn't comfortable with it in curvy, mountainous situations. I was much more relaxed when we switched to a DRW truck and things felt more stable.

Rob
 
First, very few RV or truck salespeople truly understand weight and towing figures.
Agree 100 percent, and frankly there's a lot more they don't know about the truck they are selling than just the towing numbers. Any vehicle you purchase (and RV's too), you should know WAY more about it than the salesperson. If not, you haven't done enough research. It is an unfortunately reality that these sales positions are meat grinders and the staff turn over like water. So there is no investment in training people in what they are selling, since they might not be there long enough for the ink to dry on their business card.

But hey, well thought out on your part and congrats on your new truck! Enjoy! Excited to hear about what RV you choose.
 
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When a newbie starts out they have gobs of info they need to absorb. The 80/20 rule is a easy formula to in most cases keep them out of trouble. As they gain knowledge and experience they can adjust to their specific situation.

IOW, I am an advocate of it for newcomers.
 
I would add that the payload sticker on the TV does not necessarily reflect the actual payload. My sticker says 4014 payload. The CAT scale with full tanks, DW and me, lunch cooler, safety gear, gooseball and chains, electronics, AND all of the options that the invoice says factory installed (but the factory didn't use in computing sticker weight) dropped our payload considerably - in our case 600lbs less than sticker.
 
I would add that the payload sticker on the TV does not necessarily reflect the actual payload. My sticker says 4014 payload. The CAT scale with full tanks, DW and me, lunch cooler, safety gear, gooseball and chains, electronics, AND all of the options that the invoice says factory installed (but the factory didn't use in computing sticker weight) dropped our payload considerably - in our case 600lbs less than sticker.
Hmm, maybe I'm just picking nits, but all that stuff you listed is part of the payload. As you load stuff into the truck, the available payload decreases. Seems to me a person just needs to be fully aware that everything added to the truck after they've taken possession is going, for the most part, decrease the amount of available payload. Like I said, maybe it's just me being pedantic. :)
 
Hmm, maybe I'm just picking nits, but all that stuff you listed is part of the payload. As you load stuff into the truck, the available payload decreases. Seems to me a person just needs to be fully aware that everything added to the truck after they've taken possession is going, for the most part, decrease the amount of available payload. Like I said, maybe it's just me being pedantic. :)

That's precisely the point. Don't take the payload sticker or what is quoted in the marketing brochures at face value - it reflects the TV as it sits delivered and not in use. It's not a realistic value by some margin - 15-18% lower in our case which I found surprising - we don't weigh that much. ;)
 
Cheers everyone. We are soon-to-be first time RVers who have just spent time diving into the research on towing requirements for trucks and fifth wheels. We just bought our truck - an F350 DRW - and are aiming to buy a fifth wheel in the spring. I thought it might be helpful to summarize a few of the things we've learned recently in case it can help others.

A couple of caveats. We have not applied these rules in practice yet, so this is just me conveying information based on research we've done, not experiences we've had. In addition, I may not be using exactly the right weight terms in each instance here. On either front, I'm happy to have any long-timers correct me. :)

That said, here's what we've learned:

First, very few RV or truck salespeople truly understand weight and towing figures. If they do, they don't share. When talking to them, keep in mind that their job is to make a sale. Our conclusion is that most of the ones we've met are honest, but they don't really know their stuff. They know the basics, but when you start getting into the weeds you won't get specific answers. It also appears fairly common that RVers push or exceed the limits on their towing capacity and get away with it, leading many dealers to tell you that "people do it all the time." One salesman told us that we could easily tow a GD 2930 Solitude with an F350 SRW, saying that if it were him he would "do it all day long," but when we ran the numbers we realized that with a sliding hitch, two passengers and two dogs, we would be at 105% of the maximum truck payload weight, even without any bags or guests in the truck. In light of that, you can't really rely on what you are being told. You must do your own research.

Second, doing your own research doesn't mean you'll get clear answers. You'll get a wide range of answers and opinions, oftentimes totally contradictory. This is a situation where you need to get all the information, then make your own decision. As Lee Iacocca once said, "think for yourself." That is necessarily going to include making your own risk assessment of what kinds of safety margins you prefer.

Third, before diving into the requirements on particular trucks and fifth wheels, learn about the 80/20 rule. This is a safety rule of thumb which basically says that you should not exceed 80% of the various weight limits on your towing vehicle. Many dealers will tell you that you don't need to apply the rule, that many people ignore it and tow their fifth wheels just fine, etc. We have found that the best and most helpful posts on the forums posted by experienced RV owners advise that you should follow the rule. There are many reasons why it makes sense: individual vehicles may vary from factory weight ratings, the manner in which you load the vehicles can affect the weight ratios, the driving conditions which you experience may vary from the straight and narrow roads which oftentimes underlie the factory's weight calculations, your two largest friends may want to pile in the truck with you and affect the payload, etc. Based on the best advice we've received, you're going to want a cushion. Doing that not only helps with actual safety, it helps with peace of mind, which is a major reason why we want to go RVing in the first place.

Fourth, when doing your planning don't make the mistake of focusing on just a truck's towing capacity at the expense of hitch weight / pin weight. The towing capacity of many newer 350 or 3500 SRW trucks is quite high. For example, a 2022 F350 SRW may be able to tow 19,000 pounds. Applying the 80/20 rule to that figure, you could safely tow a fifth wheel with a full (i.e., GVWR) weight of 15,200 pounds. But if you don't also pay attention to the payload figure, you may buy a fifth wheel that you can tow but that may make the overall weight of your truck too high when you add other parts of the payload like passengers, dogs, bags, weight of the tow hitch installed in the bed, etc.

So when buying a truck, always look at the payload sticker that is on the truck (ours was on the door jam). For Ford trucks, it says that the maximum weight of passengers and cargo is X pounds. We were told that, in applying this figure, you don't take into account the weight of the fuel in the truck - that is already factored in. They are really talking about the weight of things you put into the fully-fueled truck, including passengers, dogs, bags, the weight of the hitch, anything else you put in the bed, etc. When deciding on a fifth wheel, the basic formula that you need to do is to take the payload figure on the sticker (for example 3,400 pounds), subtract the likely weight of passengers and cargo that you put in the truck (for example 1,000 pounds), and then the remaining number gives you the weight that the truck can safely handle from the weight of the fifth wheel sitting on your hitch in the bed of the truck (in this case, 2,400 pounds). There are other weights such as axle rating that you also need to review, but it seems to us that those numbers are pretty safely met if you are within the limits on towing capacity and hitch weight.

Fifth, when doing the calculation of hitch weight from the fifth wheel, you will get widely varying figures on what percentage of the fifth wheel's weight will be transferred to the truck. The typical ratios that we saw ran from 15-25%. It appears that, in recent years, the percentage has dropped as fifth wheel manufacturers have revised their manufacturing. For most Solitudes, it looked like the dry weight ratio (i.e., as the empty vehicle comes out of the factory) is roughly 20%. But the percentage that is actually achieved in any given circumstance, which depends on what you put in the fifth wheel and where you put it, makes a huge difference. For example, if you have a fifth wheel weighing 15,000 pounds fully loaded, if you load it in such a manner that the weight ratio going to the truck is 15%, then 2,250 pounds is being placed on the bed of your truck. If, however, you load it so that the ratio is 25%, 3,750 pounds is being applied. That may not make a huge difference if you have a dually / DRW truck, which oftentimes have payload capacities in the 5,500 range, but it can make a huge difference if you have a SRW. Even at 15% you may be close to or exceeding the payload capacity of a SRW truck. If you load the fifth wheel in such a manner that you are at 25%, you will likely be way over the limit.

When buying a truck and a fifth wheel, you also have to recognize that you cannot accurately know in advance what ratio would be applied until you actually get out there and start using your fifth wheel. Before you buy it, you're not allowed to take the fifth wheel off the dealer's lot to go to a weighing station and test it with your truck. So you have to plan ahead. The most helpful posts that we saw from RV owners said to make sure that your towing vehicle could handle the weight of a fully loaded fifth wheel with a 25% weight ratio on the hitch. That's obviously a conservative approach, but we decided that it made sense for us, and hence we've gone with a dually rather than an SRW in order to be able to tow fifth wheels the size of a Solitude.

Sixth, there is virtually no information out there on the question of whether you should apply the 80/20 rule to the truck's payload weight in addition to towing capacity. Most dealers told us that no one had ever asked the question, or that the 80/20 rule only applies to towing capacity but not hitch weight. There does not appear to be a clear answer. Since the 80/20 rule is just a common sense rule of thumb to increase your safety margin, we've decided to apply it to hitch weight as well as towing capacity. We don't want to be towing our fully loaded fifth wheel up the Rocky Mountains in high winds with friends or family in the back seat and then find out we should have been more conservative.

Seventh, when buying a fifth wheel make sure that you don't rely just on the factory ratings for things like UVW (unloaded vehicle weight); look at the sticker that actually appears on that particular vehicle. When looking at one fifth wheel, we found that the dry weight for that particular unit was a few hundred pounds over what was on the Grand Design website as the standard UVW. You need to look at the number that applies to your particular unit when starting your calculations.

Eighth, there are lots of posts out there from RVers who said that they made the mistake of trying to drive a large fifth wheel with an SRW, only to realize after the fact that they needed a DRW. We've taken that to hear.

That summarizes what we've learned so far. As noted above, since we're new to this take these comments with a grain of salt.

We're looking forward to meeting some of you when we get out on the road! :)

My experience buying a tow vehicle was a little different. We had to sign a document stating that the salesman discussed payload - the document even states the max payload. 5th wheel shopping was just the opposite. I went in with my tow vehicle numbers and every dealer ignored them - all about the sale.

There are a lot of factors that go into max payload for a truck, the biggest being the GVW set by the government. There is a safety margin built in simply because there are so many variables in how the vehicle is loaded - moving the hitch location slightly forward or behind the axel can have a significant effect on weight distribution and handling.

Loading the 5th wheel is a whole different story. Adding fresh water will typically lower pin weight but increase trailer axel weight. Front basement storage tends to disproportionately add pin weight. I have seen people get too invested in the numbers on paper and ignore the actual scale weights. As others have stated, hit the scales - weigh the truck fully loaded (front axel then whole truck). Hitch up the trailer fully loaded, then weigh again - front axel, whole truck, then the whole package. Adjust the load accordingly.
 
"There are a lot of factors that go into max payload for a truck, the biggest being the GVW set by the government."

I'm not sure I've ever heard of non-commercial GVW being set by the government. Can you expound on that?
 
"There are a lot of factors that go into max payload for a truck, the biggest being the GVW set by the government."

I'm not sure I've ever heard of non-commercial GVW being set by the government. Can you expound on that?

This from the California DMV…

Excluded Vehicles—The following vehicles are excluded from the CVRA:

Pickup trucks continue to be registered by the unladen weight and assessed a weight fee regardless of the vehicle’s GVW. The unladen weight of a pickup cannot exceed 8,000 pounds and its GVW rating must be less than 11,500 pounds.


More about the difference between a commercial and non-commercial registration.

Feds use this standard...
(a) Heavy-duty pickup trucks and vans are pickup trucks and vans with a gross vehicle weight rating between 8,501 pounds and 14,000 pounds (Class 2b through 3 vehicles) manufactured as complete vehicles by a single or final stage manufacturer or manufactured as incomplete vehicles as designated by a manufacturer. See references in 40 CFR 86.1801-12, 40 CFR 86.1819-17, 40 CFR 1037.150, and 49 CFR 535.5(a).

(b) Heavy duty vehicles above 14,000 pounds GVWR may be optionally certified as heavy-duty pickup trucks and vans and comply with fuel consumption standards in 49 CFR 535.5(a), if properly included in a test group with similar vehicles at or below 14,000 pounds GVWR. Fuel consumption standards apply to these vehicles as if they were Class 3 heavy-duty vehicles. The work factor for these vehicles may not be greater than the largest work factor that applies for vehicles in the test group that are at or below 14,000 pounds GVWR (see 40 CFR 86.1819-14).

(c) Incomplete heavy-duty vehicles at or below 14,000 pounds GVWR may be optionally certified as heavy-duty pickup trucks and vans and comply with to the fuel consumption standards in 49 CFR 535.5(a).


The big three have consistently (until just recently) kept their 250/2500 series in the class 2b range (max GVW 10,000) and 350/3500 series in the class 3 range (max GVW 14,000).
 
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I would add that the payload sticker on the TV does not necessarily reflect the actual payload. My sticker says 4014 payload. The CAT scale with full tanks, DW and me, lunch cooler, safety gear, gooseball and chains, electronics, AND all of the options that the invoice says factory installed (but the factory didn't use in computing sticker weight) dropped our payload considerably - in our case 600lbs less than sticker.

I thought only dealer installed options are not included. Factory installed stuff should be.

The payload sticker includes a driver and not any of the “stuff” like tow hitch etc or any passengers and fuel. That is all part of payload. At least that was my understanding, you do need to add that stuff in to the uvw of the tow vehicle.

That’s why I do three weights with my tt (empty truck, loaded truck, loaded truck and trailer). Sometimes a fourth weight to include with and without the tow bars for wdh. I only weighed my trailer empty once when I first bought it. For fiver owners that would be three weights.

Bill
 
I thought only dealer installed options are not included. Factory installed stuff should be.

The payload sticker includes a driver
Bill

I think this varies depending upon the manufacturer. I've never gotten a clear concise statement from corporate (and I have asked) on whether they include the phantom 150lb driver and full tanks or not for factory sticker - I've seen 'unofficial' Stellantis and FCA documentation that is completely contradictory.

My invoice also showed some factory installed options (running boards, spray bedliner for example) that the dealer insists that they installed. The shipping weight of my truck was 7852 which doesn't add up to the GVWR minus Payload on the sticker. About a 430lb discrepancy.

Point being, if I wanted to order a truck, there is no definitive way to determine what the payload will really be. Went through the same when we ordered the 310 and tried to determine how much weight some options would add to the trailer/pin weight.
 
This from the California DMV…

Excluded Vehicles—The following vehicles are excluded from the CVRA:

Pickup trucks continue to be registered by the unladen weight and assessed a weight fee regardless of the vehicle’s GVW. The unladen weight of a pickup cannot exceed 8,000 pounds and its GVW rating must be less than 11,500 pounds.


More about the difference between a commercial and non-commercial registration.

Feds use this standard...
(a) Heavy-duty pickup trucks and vans are pickup trucks and vans with a gross vehicle weight rating between 8,501 pounds and 14,000 pounds (Class 2b through 3 vehicles) manufactured as complete vehicles by a single or final stage manufacturer or manufactured as incomplete vehicles as designated by a manufacturer. See references in 40 CFR 86.1801-12, 40 CFR 86.1819-17, 40 CFR 1037.150, and 49 CFR 535.5(a).

(b) Heavy duty vehicles above 14,000 pounds GVWR may be optionally certified as heavy-duty pickup trucks and vans and comply with fuel consumption standards in 49 CFR 535.5(a), if properly included in a test group with similar vehicles at or below 14,000 pounds GVWR. Fuel consumption standards apply to these vehicles as if they were Class 3 heavy-duty vehicles. The work factor for these vehicles may not be greater than the largest work factor that applies for vehicles in the test group that are at or below 14,000 pounds GVWR (see 40 CFR 86.1819-14).

(c) Incomplete heavy-duty vehicles at or below 14,000 pounds GVWR may be optionally certified as heavy-duty pickup trucks and vans and comply with to the fuel consumption standards in 49 CFR 535.5(a).


The big three have consistently (until just recently) kept their 250/2500 series in the class 2b range (max GVW 10,000) and 350/3500 series in the class 3 range (max GVW 14,000).
Ah, you have to love bureaucratic nonsense. I think I'll do as I've always done, ignore it. :)
 

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