Doug,

I'm not saying that no one should pull a fiver with a SB; I'm just not interested in the fivers I've seen that would work with my shortbed. Floorplans were small and cramped - less room than my TT.

The first dealer I went to and looked at fivers had two shortbed trucks sitting in the parking lot that had fiver hitches in the back. Both of them had the hitch centered slightly behind the rear axle. This really bothered me and I would not tow under those conditions.

I looked at more than a dozen models at several dealers, and got the minimum clearance distance for all of them. I found three that could mount right over the axle or maybe 1" forward. All the others would have to be behind the rear axle, or I would need a slide hitch to turn at all. This means that as I am entering anything more than a mild corner, the hitch will slide from right in front of the axle to right behind the axle, and the front suspension goes from loaded to unloaded. I don't like the idea of that at all.

Also, some of the fiver hitches would require the removal of my B&W turnover ball gooesneck. I don't use it, it came with the truck, but had hoped to add the fiver companion rather than removing it. It sits 4" in front of my rear axle and would put the weight of a trailer right where I want it.

Also, since a 2500 has a GVWR of 8,800 (pre 03), that limits my pin weight to about 1,300 to 1,500 lbs. My curb weight is over 6,800 before passengers. Of course, I would gain 100 because the tonneau has to come off for the fiver to hook up. So at 6,700, I add a family of 4 and the typical gear needed in the cab to satisfy the kids on a long drive, plus the weight of a slide hitch, and I'm now looking at 7,400 to 7,500 lbs. (maybe more).

Since a fiver should be close to 20% pin weight from what I was taught. This means that my fiver is now limited to 7,500 lbs GVWR. Dry weight would likely be below 6K. Fiver floorplans in this weight range are limited and significanlty lacking in size and amenities.

My TT weighs 7,000 loaded. I have an Equalizer weight distributing hitch with 4 point anti-sway control. My tongue weight is between 800 and 900 lbs. depending on the exact load. The trailer and truck ride perfectly level while towing. The trailer is listed as a 25' model, and is 28' from bumper to ball. I have never had a single sway problem with this setup.

My trailer is actually larger inside than the fivers that would fit my weight limits, and fits my family's needs better. It also leaves me safe room for extra cargo if needed.

In this configuration, I am 6K below my GCWR, and 800 lbs. below my GVWR. With the Dana 80, I am way below my axle ratings. I see hundreds of 3/4 tons trucks pulling fivers here every summer and the majority of them are well over these limits.

Is any TT configuration ideal for towing safety - no. Neither is any fiver though. Nothing is ideal. Can they be adequately safe - yes.

I can definitely say that I would rather be pulling my current trailer than a 10K fiver that would have a 2K pin weight sitting right over or even slightly behind my rear axle.

So while fivers are not out of the question for SB trucks, I found the limitations to be far too restricting for my situation. I definitely believe a fiver is in my future, but it will be behind a 3500 dually. ;D

 

Great comments, esp. wrt 2500s pulling heavy 5vers you know will exceed GVWR by a bunch. of course, thats the beauty of the newer 3500 SRW. and you're right about the 5ver floor plans that are roomy -- most won't work with a 2500 (and stay within GVWR) so you and I are on the same page there! I just traded my 02 2500 for that reason -- to get an 04 3500 so I could handle a reasonable 5ver.

hitch installed behind the axle: yikes, gotta agree with you there. I'd stay away from that dealer!

re: sliders. pretty much manditory for the SB, but when done well, very effective and safe. by the time the slider goes behind the axle, you're traveling slow enough and for a short enough period of time that the weight shift doesn't matter. you shouldn't be in a hurry in that tight of a corner anyway. Especially for us with the CTD up front, the momentary weight shift slightly behind the axle is inconsequential -- the numbers show a very very VERY small lift on the front axle. definatetly a don't care.

The PullRite solution, for example, is mounted just 4" front of the axle (if memory serves) and slides well behind it in a tight corner. no problemo when you're grinding through that tight of a corner you're probably going 2-4 mph if that. With 1000 lbs over the front axle just from the engine, there's just no danger when the hitch slides back.

Also, I gotta agree with you on the smaller trailers. in that size range the trailers with slides are pretty cool, and you can keep the shell on your truck bed if you have one. Just my opinion, but I think by the time you jump up into a 5ver, you should be in at least a 3500 SRW, a move that I just made. I can't agree with you more about overloaded 2500s -- I struggled with that question myself when I started running the numbers, and quickly concluded that I didnt want to put that much hitch weight into a 2500. However, the new 3500 SRW with a PullRite will pull a nice medium sized 5ver in the sub-32 foot range, and a 2,000=2200 lb hitch weight.

So I quickly traded my 02 for an 04 3500 SRW!

I also agree with you in the sense that for the over 30-32 foot class of larger 5vers, the dually is the only way to go. You can get some serious pin weights on those.

 

[quote author=Doug link=board=11;threadid=19429;start=30#msg185233 date=1063703551]
Especially for us with the CTD up front, the momentary weight shift slightly behind the axle is inconsequential -- the numbers show a very very VERY small lift on the front axle. definatetly a don't care.
[/quote]

To illustrate what I mean, here's a little brain teaser for those interested: Suppose you have a SB truck with a 140" wheelbase (distance between axles), and you have 2,000 lbs loaded directly over the rear axle. Then you move the sliding hitch back so that the 2,000 lbs is now applied behind the rear axle by 4". Here's the quiz question:

1. When you moved the slider hitch back, by how much (how many pounds) did the front axle get lighter?

and the bonus question:

2. At the same time, did the ground see any change in the rear axle weight, and if so, how much?

I'll post the answers later!

 

Doug,

I haven't had much coffee yet but here goes.

#1. Equation for force on a class one lever is:
Fe x De = Fr x Dr.

Fe = 2000 lbs.
De = 4"
Fr = ? (what we're trying to solve in this example)
Dr = 140"

Simple algebra shows that Fr = 57.143 lbs. So the front axle weight is reduced by 57 lbs.

This is simplified a little bit, because the fulcrum is not directly in contact with the plane of the lever. It is about 18" below the plane of the lever. But it is close enough for example.

The measured change in front axle weight will be the same whether the engine is a V8 or a CTD. The difference will be in the percentage change in front axle weight, which will be smaller for the CTD.

#2. If we assume that the pin weight on the fiver remains constant, then the total combined weight on both axles must remain the same. This means that if the front axle weight is reduced by 57 lbs., then the rear axle weight must be increased by 57 lbs.

In reality, when the weight shifts behind the axle, there will be some reduction in rear height. This reduction in rear height will be small, but it will increase the pin weight by shifting a small fraction of the fivers weight from behind the fivers fulcrum point to in front of the fivers fulcrum point.

The increased pin weight will be added to the rear axle weight. It will also increase the amount of force being applied to the fulcrum in question #1. This means there will be a little more than a 57 lb. reduction in the front axle weight.

So for example, let's say the increase in pin weight is 30 lbs. Our equation is now:

Fe x De = Fr x Dr.

Fe = 2030 lbs.
De = 4"
Fr = ? (what we're trying to solve in this example)
Dr = 140"

The decrease in front axle weight is now 58 lbs. But the increase in rear weight is now 78 lbs. The 58 lbs. transferred from the front axle, plus the 20 lb. increase in the pin weight.

Real world numbers would vary greatly depending on the exact truck and trailer combination.

So how did I do? It's early, so I might have missed something. Let me know if I did.

 

Doug,

You're point about the slider movement being a nominal change, and only happening at very slow speeds, is very true. I guess it's more the thought of a dynamic pin weight and location that scares me. I would already be pushing the limits of the truck and to have it moving around back there makes me nervous. But after looking at the numbers, yeah, the slider would be the least of my safety concerns.

I think the biggest reason why I have ruled out a fiver with my current truck is the wifey. Gotta love her, but she doesn't have inexpensive taste. She barely bats an eye at standard fivers with typical features. She has a knack for walking straight to the fiver that has the features like double slides, a 35" TV and a fireplace. I know we'd end up with something in the 12K to 14K weight range. :- That's why anything below a 3500 dually will be out of the question.

Bummer, huh? ;D

 

Maybe it's time for a new truck. ;D Gotta keep the wife happy you know!! ;D

 

good job thecatsfan! 57 lbs and we have a bingo. just sum the moments. and yea, it was a simplification just to show how small of a change in the actual weight distribution will occur, and how drastic the driving condition has to be in order to incurr that small change. Especially with a PullRite, where the slide is continuously variasble and dependant on angle -- you gotta be nearly jacknifed to acheive that kind of shift.

yup, the front axle absolute weight change in lbs will be the same no matter what. And the point I was trying to highlight, which you also caught, is that because of the heavy CTD, the percentage change in weight distribution will be extraordinarly small.

another part of the approximation that I assumed would be inconsequential is the change in rear height. Your numbers seem plausible, and account for perhaps another pound lift on the front axle! So with 4,277 lbs already on the front axle (3500 SRW HO 6 speed) we're talking on the order of a whopping 1% change in front axle weight.

So we can safely say that a properly set up slider on a SB presents no geometric or weight distributing changes of any real consequence. dynamic pin weight is only dynamic when turning really sharp and slow corners (PullRite) or after you have stopped and unlocked the slider (all other slider hitches). I really like the PullRite in that regard because it slides only as much as it needs to, according to the angle you make with the trailer. very cool. location constraints of the hitch in the SB is a non-issue as well -- as long as its a PullRite (my opinion). I do agree with you that not nearly enough care is given (by the dealers) in recommending and supporting the SB solution. You gotta own those details and make sure to maximize the safety of your family!

So really I share your nervousness with 2500 SB trucks and traditional sliders that have not been carefully installed, and fully agree with your decision not to pull a 5ver. On the flip sie, I would pull a (medium) 5ver with 3500 SRW and a properly installed PullRite. nothing less, however.

hey I hear you on the wifey -- I'm in the same boat, except that my wife and I agree that the large 5vers are not for us right now, and that we'll stick to the medium ones (which I wouldn't pull with a 2500 either). Also, we like to drive empty up in the mountains for light 4WD exploring which of course would be out of the question for a long bed and certainly a dually. Also, we're content with the medium sized 5vers because soon it will be just the two of us and we don't need all that room. there are a great many of the remote camping spots out west here that have ~30-31 foot limits too, and a 30' 5ver is no longer (total vehicle length) than a 24 foot TT. So we're right in that spot (~30' length region) where the benefits of the 5ver are large, and yet I refuse to buy too much trailer for my truck

Really, you're right about the larger 5vers. duallie it is. especially the 4x2 6-speed. what a towing animal that beast is. in the meantime for us, I think DC really nailed it with that 3500 SRW and its 2800 lb payload capacity, and softer ride (than the 2500). and my black one is sitting at the dealer getting accessorized right now!

 

Yeah, I would love to have a 3500 SRW. What a nice setup that is. Problem for me was they didn't exist on the used market when I was ready to buy, so I didn't have that choice. I like to buy low mileage used vehicles that are one to two years old. Typically save at least 30% that way.

Hoss,

Keepin' the wifey happy is kinda like farmin'. It's an everyday job and there ain't no holidays!