We are looking at Heartland Big Horn, 40'. Don't have a truck yet, but like the Ford F250 turbo diesel V8. Specs can be confusing. Do we need to go to F350 or will the F250 turbo be ok?

Start with the rating of the truck's rear axle. Next, figure out the 5th wheel's pin weight (5th wheel's GVWR x 20%). Now pick a truck that has 20% more capacity than your trailer's pin weight. With that information in hand ... you'll realize that you need a 350/3500 truck of the manufacturer of your choice with Dual Rear Wheels. Anything less is (probably) not legal and (possibly) dangerous. The F250 is likely both. You need a 350/3500 DRW truck as a minimum. Bigger is better. Buy MORE truck than you need. Don't let anyone talk you into less.  I know you have been told that a 3/4 ton truck will "tow it fine".  While theoretically possible, it will cost you in the end.  It will cost you more money to do it right the second time than it will if you buy the right truck the first time ... ask me how I know this.😎

-- Edited by RonC on Thursday 22nd of September 2016 09:11:56 PM

-- Edited by RonC on Thursday 22nd of September 2016 09:13:09 PM

-- Edited by RonC on Thursday 22nd of September 2016 09:13:51 PM

For your safety and for others, please get a 350 DRW and more !

Thanks

p.s. diesel

Yup, do NOT skimp on your truck. We are towing a 41' Heartland Landmark behind an F-450 DRW. We've been through mountains and all kinds of rough terrain, and that big Super Duty handles it all without any problem.

Note that there are a few different ways to ask the question you posed:

1. "Will this truck tow my trailer?" That just asks whether the truck can move the rig. Many trucks could physically pull a trailer that's too large for their specs, so this question is really not specific enough.

2. "Will any of this truck's maximum weight specs be exceeded if I tow my trailer with it?" This is the minimum acceptable standard. You need to look at two numbers for the truck:

(a) its Gross Vehicle Weight Rating (GVWR), which is the most weight that the truck can carry on its own wheels. Compare the truck's GVWR to the empty weight of the truck + passengers + cargo + fuel + the pin weight of the trailer; that total must not exceed the truck's GVWR. As RonC said, you can estimate the pin weight as 20% of the trailer's GVWR.

(b) its Gross Combined Weight Rating (GCWR), which is the most weight that the truck can tow. Compare the truck's GCWR to the combined weight of the truck, passengers, cargo, fuel, and the GVWR of the trailer; that total must not exceed the truck's GCWR.

3. "Will this truck safely tow my trailer?" This in my opinion is the most important question. Assuming your weights are under the truck's maximums, are you right at the limit, or do you have adequate safety margin? You have to consider not just the truck's ability to haul the trailer up a hill, but also (maybe even more importantly) its ability to slow the trailer down coming downhill, while remaining stable. Personally, I want considerably more truck than just the minimum needed.

In our case, the F-450's GVWR is 13,300 lbs., which is 1,000 lbs. more than the actual weight with the trailer hitched. And our combined weight (truck and trailer) is 24,250 lbs., well below the F-450's 33,000 lb. GCWR. I like having that generous safety margin.

I don't know the weight of your trailer, but as others on this thread have said, I'm almost certain you need at least an F-350 DRW. The dual rear wheels significantly increase stability and stopping ability. But you can probably get an F-450 for not much more money, and it might be a worthwhile investment. And once you have your truck and trailer fully loaded, be sure to get a wheel-by-wheel weighing to ensure none of the tires are overloaded.

RonC wrote:

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Although David didn't mention it, I believe the F450 has a tighter turning radius than the F350. This can help with maneuvering both when towing and when solo.

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Hmm, I didn't know that, Ron! But good point. 

There are other differences to look at as well, like the axle ratio - a higher number gives you more torque but lower fuel economy. 

By the way, I'm not biased toward Ford, even though that's what we have and we're happy with it. I see a lot of people towing big rigs with the RAM 3500 DRW, for example, so it seems to be quite popular as well.

I would buy a 450 over the 350…almost the same physical size and the 450 is overall a better towing vehicle. However…on any pickup what you're worried about is the rear axle weight…as noted in the other replies you can guess this but I would use the 25% of loaded trailer weight rather than 20…or better yet see if anybody has a similar size full timing Big Horn and can give you their numbers. The towing capacity is not the limiting factor usually…it's the rear axle limit. Don't forget to include an aux tank if you're putting one in and hitch/tools/whatever stored in the bed as well as full fuel and people in the cab.

The second big issue is bed rail to bottom of the bedroom clearance…recent model trucks have pretty deep beds and depending on which hitch you put in that can be an issue.

My guess is that with a 40 foot rig…a 350 just might squeak under the limits if you don't add an aux tank…but it would be close and without running the numbers you really can't tell. You can get the as delivered weight and pin weight from the dealer or Heartland…but then don't forget to add in dealer installed options, water, and cargo you're going to add…if you have the as delivered weight and pin weight then you can do the ratio there…add on some fudge factor (i.e., if as delivered is 22% then use 25 for your calculations) then assume that you've added weight up to the max cargo capacity or GVW for the trailer and figure out the associated pin weight…which then goes onto rear axle load after adding fuel, hitch, tools, and people.

Best guesses are just that though…a guess. Much better to get some real numbers and do the calculation…I'm sure that either Bill or I would be happy to send you a copy of his Excel worksheet for this…or there are plenty of them on the web…ya just got to understand RAW, GVW, GCVW, towing capacity, trailer weight, and pin weight and how they relate.

RonC wrote:

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Neil's comments are important. Most "new to this" folks get lost pretty quickly in all the weights and what will/won't work. I'll admit that it took me awhile to "figure it out". But it is very important for you to have a clear understanding of what your needs are and if the truck you are considering can meet (better yet exceed) those needs. I haven't seen the spreadsheet that Neil is alluding to but I will tell you that he and Bill are two pretty sharp guys on this stuff. Take him up on his offer.

---

 Took some reading on different forums, to finally figure out what will and won't work for towing weights.

We are starting our search into the RV world, and have done it backwards. We bought the truck and now looking for a trailer. To be honest, we had no idea about looking for an RV when we bought the Toyota Tundra.

381 HP, 401lbs torque, 4:30 gears, class IV receiver, 38 gal fuel tank, TRD sway bar, tow package with brakes.

We are looking at ultra-lights to meet the towing capacity of the vehicle, and so far have been looking at bumper pulls, but Linda wants to look at some 5th wheels as an alternative, that might pull better.

Our truck with the mods has a load capacity of gross 1300 lbs if we go 5th wheel for pin weight, occupants, gear.

We have been looking at 28' ultralight models that have a wet weight of around 7000lbs. The truck can easily handle that with the WDH as far as we can figure.

We have no clue what the wet pin weight of a 28' fifth wheel ultra light runs, and hope we can get some info from those that run a 5th wheel with a 1/2 ton.

Dennis, you should determine what type of trailer (travel or fifth wheel) will fit your living needs before deciding on a truck to tow it with. If you stick with the Tundra your options may more limited than you might like. It is also true that you may not need or want a substantial RV for your particular situation.  Since you spend more time in the trailer rather than the truck It seems like you would want to ensure those demands get met before the method of towing it around are determined. JMHO.  

It is also granted that while getting the truck first limits your choices of RV, the reverse is true also to a degree. If you find the rig you like is on the large size then your towing options are also somewhat limited to larger trucks. 6 of one, half a dozen of the other. 

We are not on the road yet and have the luxury of time and picking what works for us... so far the rigs we have looked at that seems to fit our needs will require a one ton dually at the minimum to do the job safely... the overriding number one consideration in my book.

FWIW, Brian

BiggarView wrote:

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Dennis, you should determine what type of trailer (travel or fifth wheel) will fit your living needs before deciding on a truck to tow it with. If you stick with the Tundra your options may more limited than you might like. It is also true that you may not need or want a substantial RV for your particular situation.  Since you spend more time in the trailer rather than the truck It seems like you would want to ensure those demands get met before the method of towing it around are determined. JMHO.  

It is also granted that while getting the truck first limits your choices of RV, the reverse is true also to a degree. If you find the rig you like is on the large size then your towing options are also somewhat limited to larger trucks. 6 of one, half a dozen of the other. 

We are not on the road yet and have the luxury of time and picking what works for us... so far the rigs we have looked at that seems to fit our needs will require a one ton dually at the minimum to do the job safely... the overriding number one consideration in my book.

FWIW, Brian

 

---

 Yeah, we are going at it backwards, but when the truck was bought we had not thought about buying a TT.

After reading a lot about load calculations and looking at 5th wheel pin weight, we have pretty much ruled them out.

We are now focusing on bumper pulls with a weight distributing hitch. There are certainly some nice options out there.  

Not saying you are going at it backwards, we all have our own priorities and limitations.  That being said, no one is suggesting that you should have a fifth wheel, that is strictly your call based on your particular needs, wants and desires. What works for you doesn't necessarily work for anybody else. There lots of options for you using the Tundra as your TV. Just bear in mind what its limitations are and your choices will become clearer. Good luck in your research.

Brian

Neil and Connie wrote:

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I would buy a 450 over the 350…almost the same physical size and the 450 is overall a better towing vehicle. However…on any pickup what you're worried about is the rear axle weight…as noted in the other replies you can guess this but I would use the 25% of loaded trailer weight rather than 20…or better yet see if anybody has a similar size full timing Big Horn and can give you their numbers. The towing capacity is not the limiting factor usually…it's the rear axle limit. Don't forget to include an aux tank if you're putting one in and hitch/tools/whatever stored in the bed as well as full fuel and people in the cab.

The second big issue is bed rail to bottom of the bedroom clearance…recent model trucks have pretty deep beds and depending on which hitch you put in that can be an issue.

My guess is that with a 40 foot rig…a 350 just might squeak under the limits if you don't add an aux tank…but it would be close and without running the numbers you really can't tell. You can get the as delivered weight and pin weight from the dealer or Heartland…but then don't forget to add in dealer installed options, water, and cargo you're going to add…if you have the as delivered weight and pin weight then you can do the ratio there…add on some fudge factor (i.e., if as delivered is 22% then use 25 for your calculations) then assume that you've added weight up to the max cargo capacity or GVW for the trailer and figure out the associated pin weight…which then goes onto rear axle load after adding fuel, hitch, tools, and people.

Best guesses are just that though…a guess. Much better to get some real numbers and do the calculation…I'm sure that either Bill or I would be happy to send you a copy of his Excel worksheet for this…or there are plenty of them on the web…ya just got to understand RAW, GVW, GCVW, towing capacity, trailer weight, and pin weight and how they relate.

---

Neil's comments bolded above are very important as is all of his post.  Many have, or will, crash the truck bed rails into the trailer even on paved roads.  All the newer trucks have high bed rails and there is only two solutions for this:  Raise the trailer (not actually that big a deal) or a hauler bed (which adds weight to the rear axle especially.  7" is desirable - 6" is too close for me but some get away with it.

On the F-350 vs. F-450 issue and rear axles, etc.:  The F-350 actually is superior to the F-450 (pickup version - not the commercial F-450) as pertains to rear axle ratings.  Same is true for the 2017 versions of both trucks.  Its math, not the badge on the side.  Be sure to make full allowance for the weight of stuff you put in the truck.  Also remember the published base weights of the truck are "stripped" so the empty weight, fresh from the showroom, will be more.  But the only way to make a good choice is to do the math and allow for at least 2,250lb (it will likely be more) of cargo in the trailer for your stuff.  Remember, carried water is "stuff" and must be added to the trailer's empty weight.

For safety and stability you need a dual rear wheel truck.  Not an F-250 / 2500HD under any circumstances IMO.  Just not an option, especially with a big fiver and 40' is big regardless of brand.  What they can tow, ratings wise, is becoming less significant with the power wars going on now.  It is what they can carry on the rear axle that is usually the determining factor.  As I usually say, its just math and experience.

RonC wrote:

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Although David didn't mention it, I believe the F450 has a tighter turning radius than the F350. This can help with maneuvering both when towing and when solo.

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 It does…Bill Napier was always unhappy that he lost the turning radius competition to me with his 3500HD. Now that we both have a 5500HD we're tied.

Neil and Connie wrote:

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RonC wrote:

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Although David didn't mention it, I believe the F450 has a tighter turning radius than the F350. This can help with maneuvering both when towing and when solo.

---

 It does…Bill Napier was always unhappy that he lost the turning radius competition to me with his 3500HD. Now that we both have a 5500HD we're tied.

 

---

Well, hey, had to let you win at something. :)  But seriously, yea, the 450 is wider up front then the 350 / 3500 series and has a better turning radius.  But not as good a rear axle weight rating as the 350 / 3500 in our model years - weird as that may seem to some.  Ya gotta read the fine print.

FurbabyMama wrote:

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We are looking at Heartland Big Horn, 40'. Don't have a truck yet, but like the Ford F250 turbo diesel V8. Specs can be confusing. Do we need to go to F350 or will the F250 turbo be ok?

---

 Looks like you got a lot of good advice on your question.  I'd like to add a little more to the thread.  GVWR of your trailer (not what it actually weighs) is the important number.  The same number for your truck (GVWR) is the number of interest to the authorities.  If the total of those two numbers exceed 26,000 lbs, then you will need a special license in most states.  It does not matter what you actually weigh, just what the GVWR is (now the actual weight does matter in that it determines if any of your various ratings are exceeded). In Texas you would be required to have a "non-CDL class A" license.  This requires you pass both a written and skills (driving) test.

This little "fact" is often not mentioned by the salesmen at the RV lot.  Mine specificaly said "no special license is needed and a 3/4 ton F250 would be plenty of truck".  Neither statement was true but I think it was due to lack of knowledge and not intentional deception.  My 5th wheel's GVWR is 15,000 lbs, I'll wager that your Big Horn's GVWR is higher than that.  Here's where the thing gets interesting, I bought an F350 SRW truck, whose GVWR was 11,400 lbs.  So 11,400 plus 15,000 equals 26,400 ... that put me over the magic 26,000, requirement for a class A license (in Texas).  That F350, when actually weighed, was over the GVWR of the truck by 950 lbs, and 200 lbs over the RAWR (rear axle weight rating).  Had I bought an F250, then The GVWR of the truck and trailer would have come in below 26,000 lbs, eliminating the class A license requirement, but resulting in a dangerously overweight truck and trailer combination.  Why is this important?  Lawyers and Insurance Companies become very interested in your weights and your license if something bad happens.  

I now have an F350 DRW truck whose GVWR is 14,000 lbs and a class A license.  This gives me plenty of safety margin in all the key ratings.  CGVWR, RAWR and GVWR of the truck.

Good Luck with your decision and be safe!

-- Edited by RonC on Sunday 25th of December 2016 05:05:16 PM

-- Edited by RonC on Sunday 25th of December 2016 05:37:23 PM

-- Edited by RonC on Sunday 25th of December 2016 05:44:04 PM

-- Edited by RonC on Sunday 22nd of January 2017 08:42:56 PM

While it is true that many operate over weight and exceed their truck's rating (most often the RAWR) and have done so for many years.  This puts undue strain on the components of the truck and can lead to reduced service life, the more serious issue IMO, is in the event of an accident involving loss of life, it becomes MUCH MORE. Like life changing liability.  I realize this is highly unlikely, but we buy insurance for a reason, and having the right equipment and being legal on the weights is pretty good insurance.

-- Edited by RonC on Monday 26th of December 2016 10:37:02 AM

Here's a quick way to find out if there are any special drivers' license requirements in your state (many states use the "anything over 26,000# GCVWR" rule):

http://changingears.com/rv-sec-state-rv-license.shtml

Rob

I believe a 3/4 ton TV would be overmatched by 40 foot Bighorn 5er. Hopefully you won't be too close behind me when emergency stopping....cause then you would be buying me a new rig...TT and TV.

new f-350 diesel  can now tow up to 32500  more than enough truck for most fifth wheels

I suggest that one doesn't go by a truck's "Tow Rating."  My 2008 Ford F450 has a big tow rating, but if one calculates the actual weights that it would take to reach that number, my truck would be over on GCVW.

Instead, look at the truck's GCVW and GAWR and not exceed either of those.

Terry

wecker1 wrote:

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Nearing retirement and seriously considering the 5th Wheel life. I think I have my tow vehicle & 5W selected but need assistance in confirming the tow vehicle is a good selection for the 5W. Tow Vehicle: 2017 Ford F350, 4x4, SRW, 6.7L Diesel, Max GVWR 11,400lbs, GCWR 28,700lbs, 5W tow rating 18,000lbs. 5W: Keystone Montana, GVR 16,670, Hitch 2,670. I think the numbers work but would appreciate your comments. Also, any experience or comments on the 5W would be appreciated. Much Thanks

---

 You are going to need the truck you chose, but in a DRW configuration.  The problem will be with the rear axle weight rating.  Full timers tend to be a little heavy anyway, and the RAWR of a SRW truck will likely be exceeded by the weight of the stuff carried in the bed plus the pin weight of your rig.  The 2,670 published pin weight is for an unloaded trailer, your loaded pin weight will probably be closer to 3,500 than 2,670.  This leaves zero safety margin and you should allow for a safety margin. The SRW truck will be at or over it's RAWR.  DRW trucks are also much more laterally stable.  When the bow wake of an 18 wheeler hits you, you'll appreciate that.  Good luck with you retirement and adventure!

That sounds about right. A SRW truck (without the trailer) will probably have a rear axle weight of between 4,000 and 4,500 lbs loaded to travel. With a 3,000 lbs pin weight, your RAW will be between 7,000 and 7,500 lbs. you can see there is no safety margin there. A DRW (my F350 DRW is rated at 9,650 lbs) will give you another 2,000 lbs rating on the rear axle PLUS the lateral stability of the DRW. Like you, I started with a SRW F350 ... once I got the weight thing figured out, I traded for a DRW truck. Ouch! That cost me a little "stupid tax" .... trying to save you from the same experience. Why is all this so important? Lawyers. When anything bad happens, Lawyers and Insurance Companies become VERY interested in your weights.

Once again great information, thank you. Couple of additional questions if you don't mind...to determine the RAW without trailer are you simply dividing the curb weight of the 4x4 truck in half to get a close approximate number? How did you figure out that you needed to upgrade from the SRW to the DRW, what were the indicators? Thanks again!

Ford publishes the payload ratings of their trucks. Depending on the configuration of your vehicle, 4000 to 4500 is usable payload for a F350 SRW. So after you subtract the roughly 3500 lbs of pin weight (rough calculation based on GVW of the trailer times 21% which is a typical percentage of total trailer weigh that ends up on the pin when fully loaded out), you only have 500-1000 lbs or less (err on the side of less) for everything else you load into the truck..., passengers, tools, the actual hitch, any other gear that you will be carrying in/on the truck itself. So you see RonC is correct when he says you are pushing up against the limits if not exceeding them. Sure, the F350 SRW can tow the trailer, but you are asking for trouble in less than ideal circumstances... think downhill, on a curve, in the rain or snow, and the sudden need to stop etc.  Safety first. Personally, I'd rather be sitting around the campfire, listening to your exciting tales of adventure, than reading about a disaster in the news or the obits. 

FWIW, Brian

PS:

I presume from the trailer specs you gave that you are considering the Montana 3730FL. The basement is smaller so your pinweight may not reach 21% only because you can't load as much gear into a smaller space, but that is in no way guaranteed. If you add in options like a genny, or decide to add solar and add'l batteries, then all bets are off. Montana's listed numbers are for the basic trailer without options added in. The actual weights you will have available will depend on the actual configuation and actual trailer as it leaves the factory. 21% of trailer GVW is about average for most 5ers in my research. I've seen it as low as 18% and as high as 25% so forewarned is forearmed.

We are not yet on the road, but we are considering rigs of similar size and weights as you, but we have already ruled out SRW in favor of DRW based on the math and our comfort zone, and sage counsel given by many on this forum.

Thanks Brian. Seems like I need to rethink my strategy and either upgrade to the DRW or consider a lighter RV. The Montana has the High Country line which is still very nice but not the Luxury line, and a model 375FL with similar layout which comes in 1300lbs lighter with 400lbs less pin weight. Very informative blog and quite honestly information that should be provided by the RV sales folks.

The common wisdom is to find the rig you like, then get the tow vehicle that will do the job and preferably with room to spare in terms of it's capabilities.

RV sales folks telling you the facts..... good one. (there are exceptions of course)

FWIW, I like the kitchen layout in the 375FL better than the 3730FL, but the trim on the 3730 is more to our taste. The new Montana 3811MS has recently come across our radar and we are making a trip to a dealer soon to evaluate it further. Of course, for us, we are a bit over 2 years from going FT, and a lot can change between now and then...

Understand and agree re the 3730 vs the 375. We're also about a year away from making our 5W purchase and will be doing a lot of research between now and then. Have been on the RV Trader.com website this morning and viewed units that we toured this weekend at the local dealer listed for several thousand less than lot listing price. Will have to remember to check the website before entering negotiations with the dealer when the time comes. Thanks again.

wecker1 wrote:

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Once again great information, thank you. Couple of additional questions if you don't mind...to determine the RAW without trailer are you simply dividing the curb weight of the 4x4 truck in half to get a close approximate number? How did you figure out that you needed to upgrade from the SRW to the DRW, what were the indicators? Thanks again!

---

 The RAW (actual weight ... not the rating) is obtained by going to a CAT scale (there is one at most truck stops) and weighing your truck.  It will give you the front axle weight, the rear axle weight (they call it the drive axle weight) and the total weight.  They won't be anywhere near 50/50.  This should be done when the truck is completely empty, but full of fuel and no passengers (let's call this weight #1).  This will give you the baseline.  Then weigh it again with the passengers you will be traveling with and loading the truck as you would when traveling (let's call this weight #2).  This will tell you how much of your total cargo carrying capacity is used up BEFORE you add the pin weight of the trailer.  Finally, weigh it again with the trailer hooked up (let's call this weight #3).  The total vehicle weight from this last weighing (#3) should not exceed the GVWR of the truck and the total weight of the passengers, cargo and pin weight shouldn't exceed the maximum cargo carrying capacity of the truck.  All of these may be calculated using the three weights you obtained.  The weight of your cargo (including the pin weight) may be found by subtracting #1 from #3. Pin weight is found by subtracting #2 from #3.

With a SRW F350, you will be very close, more likely over, the RAWR of the truck and very likely to exceed the GVWR as well.  The reason I gave you the weights I used was that my SRW F350 4WD trucks RAW was 3920 loaded to travel without the trailer and 7120 with the trailer hooked up.  My RAWR was 7,000 ... I was over by 120 lbs ... but more importantly, I was 980 over the trucks GVWR.  I weighed 12,380 and my truck's GVWR was 11,400.  The math told me my pin weight was 3,200.  For those reasons, I switched to a DRW F350.  My DRW truck has a GVWR of 14,000 and a RAWR of 9,650.  This give me thousands of pounds of cushion both on my rear axle but also on the truck's GVW.  The towing stability in wind, mountains and when being passed by 18 wheelers is day and night between the SRW truck and the my new DRW truck.

All of this discussion ONLY is to help you make a good decision on the tow vehicle.  Once that is done, then the weight of the trailer, weight of the axles, wheel by wheel weights all come into play ... but that is whole different discussion.

Good Luck.  Be Safe.

-- Edited by RonC on Thursday 16th of February 2017 11:03:13 AM

-- Edited by RonC on Thursday 16th of February 2017 11:04:28 AM

-- Edited by RonC on Thursday 16th of February 2017 11:12:03 AM

wecker1 wrote:

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Thanks Brian. Seems like I need to rethink my strategy and either upgrade to the DRW or consider a lighter RV. The Montana has the High Country line which is still very nice but not the Luxury line, and a model 375FL with similar layout which comes in 1300lbs lighter with 400lbs less pin weight. Very informative blog and quite honestly information that should be provided by the RV sales folks.

---

 The previously provided info on weights was pretty black and white ... this advice is not.  This is strictly IMO.  I'd suggest you buy the trailer you WANT ... it is going to be your home and if you buy a lighter one that isn't the one you really want, you'll regret it eventually and that will likely cost you some money.  If the trailer you want requires a bigger truck, then so be it.  Until you get over 18,000 GVWR on the trailer, the DRW F350 will likely handle it.  As it gets heavier than that, you will need to do careful calculations and may need to move up and get a bigger truck.  I suggest that you always maintain at least a 20% reserve capacity on all your ratings.  Brian suggested that you buy the trailer first then buy a truck that will handle it.  That's great advice.  But the same thing can be accomplished once you have ABSOLUTELY settled on the trailer you want.  Once that is done, then you can buy a truck to handle it.  I got my truck at year end with big discounts and dealer incentives, so I got a screaming good deal ... thus the 2016 truck.

-- Edited by RonC on Thursday 16th of February 2017 11:39:40 AM

A comment should it be helpful in addition to Ron's suggestions.

The front axle weight of a pickup type truck, with and without a 5th wheel trailer in most cases, won't change hardly at all. Little to be significant.  The 5th wheel hitch, if properly installed, is just barely ahead of the rear axle.  So if one weighs the truck fully load with fuel, people and tools don't expect the front axle weight to change much with the 5th wheel pin weight.  I've seen my former 3500's change like 25 lbs with and without the 5th wheel trailer and that's with 4K+ pin weights.  So the critical number is the rear axle and naturally the combined weight.  Once you have the fully loaded weight of the truck on each axle that becomes a worst case situation with any given trailer weight change.

(Naturally this does not hold true for HDT's that are "singled" and have the hitch way behind the rear axle.  But that's a totally different design issue and discussion.)

Bill

Wecker1
I noticed that you are from GA. If you intend to maintain that as your "domicile" (where you are licensed, where you vote, where your vehicles are registered, where you get your mail), then you will need either a non commercial class E or F drivers license due to the Combined Gross Vehicle Weight RATING (not what it actually weighs) of your truck and trailer exceeds 26,000 lbs. Just FYI.

-- Edited by RonC on Thursday 16th of February 2017 04:03:44 PM

We're still in the R&D stage and think we have our truck and 5W selected. One question I still have is this, does the axle ratio really make that big of a difference with the combo that we've selected?

The 5W is a Keystone Montana 3731FL, 39'6", GCVW 16,675... The truck is a 2017 Ford F350 Lariat CC, 4x4, LB, DRW, 6.7L with the 3.55 Limited Slip axle. I've selected the 3.55 in an attempt to maximize mileage but am curious if this is considered a wise choice or should I consider the 4.10 for greater pulling capacity.

Any advice provided will be greatly appreciated. 

The 3.55 gears will lower your CGVWR rating by about 4000 pounds. However at 36,000 CGVWR the only difference you'll likely notice is a bit slower off the line with a 16675 trailer in tow with the 3.55s vs 4.10s. Compared to DRVs OR New Horizons for example, the Montana is relatively light and should not be any trouble for the truck you are looking at. A slightly higher gear ratio will not significantly lower your MPG and will probably offer you better compromisee for towing and fuel mileage.

JHMO, Brian

Thanks Brian for the quick response and confirming what I thought I knew.

You can get behind the 8-ball gearing too tall trying to get fuel mileage. I had a truck (diesel with a higher-ratio rear end) that didn't like 65 MPH (where I like to live on Interstates). At 65 it didn't like the low RPMs on the engine and would constantly shift down to 5th gear. 67 - 68 and it was happy. The new truck (very similar engine and transmission but with a lower final gear ratio) turns a couple hundred more RPM at a given speed compared to the first truck. It's very happy at 65 and doesn't even think about shifting down until we hit a significant grade. Interestingly, the fuel mileage while towing is identical. My theory here is that I'm not into the throttle (or turbo) as much as with the previous truck. Around town without the trailer is a different story - but that's not what we have the truck for.

Rob

Thanks for the additional information Rob. If you don't mind me asking what ratio rear-end do you have in your Ford? I like you will probably sit on 65mph as anything higher in my mind is too much.

Regards,

Wayne