Weight Distribution Question

[drboyd]

If the 1200# bars are good for essentially any tongue weight, as they're saying, why bother to make any different bars? Why not make 'em all the same?

On the other hand, that's what Equal-i-zer does. They've got one bar weight, and that's that.

I still haven't thought thru the mechanics of the bar weights enough to provide an adequate critique of the bar weight issue. My thoughts are running along the line of examining the incremental tension of moving the next 1/2 inch, and how that affects the dual cam operation....

[bryanl]

Spring bars are part of a suspension system and should be considered much the way springs and shocks are. A lightly loaded suspension tends to ride rather harsh while an overloaded suspension tends to cause handling problems.

In most cases, you can tell if your spring bars are set properly if they have no load after lifting the ball five inches or so (6-8 quoted several times in this thread).

Spring bars are rather stiff so the flexing can be too small to notice - and should be in normal circumstances.

The DC sway control needs a proper weight on its cams to develop effective control so these hitch types are perhaps more sensitive to proper adjustments than other hitches.

I am curious about the statement that the Equalizer hitch uses the same spring bars for its three weight ratings. If so, what is the difference between the Equalizer hitches of various weight ratings?

[jcanavera]

I spoke to the Reese factory folks when I purchased the Airstream. My question was regarding my existing bars which were 750# rated. Since that was the published hitch weight for the Safari I asked the question of whether I should upgrade or not.

I figured that with propane load and other front loading of the trailer, the weight would most likely exceed 750#. Their answer was that I needed to understand that my bars would end up carrying more weight than the rated hitch weight.

Especially concerning was the fact that when you hit dips in the road which normally forces the trailer to dip the tongue, an even heavier load is placed on the bars. They have seen situations where bars have snapped under such conditions and suggested that I move to 1,000# bars which I did.

I've never asked them about the interaction of the weight load and bend of the bar and the dual cam sway function. I'll drop them a line and post back their response.

Jack

[85MH325]

Originally posted by Leipper

In most cases, you can tell if your spring bars are set properly if they have no load after lifting the ball five inches or so (6-8 quoted several times in this thread).

Thanks for the more precise measurement, Bryan. I obviously have never measured or paid a great deal of attention to the exact amount of travel necessary.

Roger

[jcanavera]

Originally posted by jcanavera
II've never asked them about the interaction of the weight load and bend of the bar and the dual cam sway function. I'll drop them a line and post back their response.

Jack

Here is the official response from Reese regarding the issues we have discussed in previous posts.

"The dual cam is weight specific in that the greater the load, the
greater the effect. However, the trailer having lighter coupler weight
requires less effort by the dual cam than the larger trailer with the
heavier coupler loads to achieve the same goals.
Question 2. - Different vehicles need their unique setup for proper towing.
The correct chain link is dictated by the vehicle "squat" and the key here
is to keep the front of the van from "lifting" with the suspension. Measure
the wheel wells before and after on both the front and the rear to see the
change. Get the front to come down a little and not as much a change as the
rear well changes and you should be fine. Too much load into the spring
bars could show an ill effect so be careful."

Hope this clarifies some questions.

[Silvertwinkie]

Hey thanks Jack. Makes sense to me!

[DPeakMD]

This may not be much help, but I'll offer it up...

In setting up my old Reese hitch I couldn't really measure much deflection of the front springs of my F350 PowerStroke Diesel Crewcab shortbed. So, I took it to the truck scales to see where the weight was going. The table below refers to the Ford Fr and Rr axle weights and the trailer axles (combined) weights with 4 or 5 links "dropped" (i.e., not under tension so 5 is more tension than 4).


Fr Rr Trailer
Truck: 4700 4050 N/A
4 Links: 4600 4840 6260
5 Links: 4780 4580 6300


This was not a scientific study. There were slight variations in the loading between measures and one was taken at another scale, but the weight distribution is roughly demonstrated.

My findings were very interesting and helpful for me in setting up the combo. However, I ended up purchasing a Hensley hitch this year! Now I've got about 200# worth of various Reese bars, brackets, bolts and 3 sizes of drop draw bars collecting dust in my barn.

[Inland RV Center, In]

Torsion bar "links" should "NEVER" be dropped.

Why?

Once in a while you have a different number of links on each chain.

Secondly, and most importantly, how many links are dropped has nothing to do with anything.

How many links "under stress" is where the attention should be placed.

Again, why?

Because you could, however accidentially, put a twist into one of the chains, therefore making that chain shorter than the other side.

Always, always, always, direct your attention to the links under "STRESS". That is the business at hand.

Andy

[bryanl]

4 Links: 4600 4840 6260
5 Links: 4780 4580 6300

this is interesting. Only 40 lb difference in nearly 16,000 indicates a good precision.

It shows that a difference of about an inch on the end of the spring bars shifted 260 lb off the rear axle 70% to front axle and 15% to trailer (15% or the other 40 lb unknown).

To get a full picture, you'd need the axle and hitch weights without the spring bars but this makes sense for a spring bar adjustment. Any idea how much this one link changed ball height? (i.e how much bummer lift you got when you took 260 lb off the rear axle?)

[dmac]

As we consider the proper spring bar ratings - we try to statically set up our hitches to have the proper ball height, seek to level the trailer and tow vehicle, and distribute the load equally between the tow vehicle front and rear axle. I think there is more going on dynamically though - because the trailer/tow vehicle junction bends... the car angles up a hill before the trailer follows, etc. Because of this more or less force is placed on the WD bars. Too-stiff bars could transfer excessive force entering hills and on the up-side of bumps. This might result in a rough ride and excess stress on the hitch and trailer frame.

Leipper - I have the Equal-i-zer brand hitch and my understanding is that the 3 different rating of hitches are due to 3 different rated spring bars.

[Pahaska]

that just about every hitch manufacturer makes several stiffness of bars (in my case, 550#, 750#, and 1000#) including Reese. And then someone calls Reese and gets the answer "just use the 1000# bars". Same thing with my hitch dealer. They just stock 1000# bars "cause it's easier that way".

I briefly used 1000# bars on my TrailManor while the dealer ordered me the 550# bars. I could sure tell the difference in ride. As dmac pointed out, it tended to drive the rear end of the low-slung trailer into the dirt going over lumps and bumps.

I subscribe to the theory that the bar should be no heavier than required to level the tow vehicle.

Besides, it is a lot more fun to lift a 550# bar than a 1000# bar.

[DPeakMD]

Inland Andy--the reference to dropped links is a colloquial way that I grew up referencing the attainment of equal number of stressed links on each side...generally there are more stressed links and it's easier to count the unused ones. I've ensured there are equal numbers on each side. Makes sense to me, hopefully no one else was confused.

Leipper--I've lost the measurements of hitch height that went along with the weights. I did make a difference, though. With more tension the trailer was nose-high/tail low in this setup. A 31' is a tail dragger anyway--doubly so with saggy axles--and this didn't help.

OK, I know I shouldn't go here...but oh well.

I've heard a good explanation of the rationale of setting up a Reese WD system. Three variables you can change: Hitch ball height, Hitch head angle, and Bar tension. (Disclaimer: change hitch ball height through adjustment of the holes that the hitch head uses in the draw bar, NOT airsprings/shocks on tow vehicle!).

Roughly speaking, here's how I think about it that makes sense to me...YMMV!

Adjust the hitch ball height to 'level' the trailer
Adjust the weight distributing bars to 'level' the tow vehicle
Adjust the hitch head angle to 'level' the bars.

Getting all of these things just right can be easy in some cases, or take a lot of tinkering in others.

Dmac--Here's the conclusion that I came to...personal opinion! I agree with you. The situation above is acheived for static not dynamic variables. I acheived a good weight distribution at rest. However, in motion, it was awful! I had acceptable sway control, but the ride was awful! It was porpoising over bumps and sectioned concrete highways were like a bucking bronco ride! I believe the spring rate of the WD bars and very heavy springs of my truck acted in concert to create the porpoising with stored (spring) energy similar to a standing wave. Shocks could not overcome this--trust me, I tried! That's another discussion for Ford truck owners.

The end result--I went to a form of sway control not dependent upon spring tension as it's premise of operation. The ride is much better now.

[bryanl]

A good education in this thread!

Dallas's Guidelines nicely summarize the variables in hitch adjustment and their goals. The caution that these are static and not dynamic is a good one, too.

We also have Andy's caution about using links under stress to measure spring bar tension adjustment with a good rationale; some guidelines for how much tension should be on a spring bar for most rigs; the need to get the proper spring bars for the loading on them; and some ideas on the safest way to load the spring bars when hitching up.

re: "I went to a form of sway control not dependent upon spring tension as it's premise of operation. The ride is much better now."

Can you fill us in? The DC is the only hitch I know where the sway control is dependent upon spring bar weight. What did you end up with and how did its weight distribution avoid the porpoising? It seems that much of porpoising has to do with speed and wheelbase - is this true?

[dmac]

I suspect that my Equal-i-zer brand hitch is dependant on the spring bar tension for it's anti-sway properties. The Equal-i-zer does not use chains to tension the bars against the trailer frame, but rather has the bars ride directly on brackets attached to the trailer frame. Friction of the bars rubbing against the brackets, and friction of the bar pivots at the hitch, are what do the deed. Less bar tension, less sway control (and visa-versa).

[DPeakMD]

Leipper--You're right, this is an interesting dialog!

To answer your question, I went with the Hensley Arrow. As I understand it, it uses a geometric linkage to greatly diminish the trailer's inputs to the tow-vehicle and hence reduce sway. Clearly, though, WD bars are part of the package.

I found that setting up the Hensley according to the directions resulted in level tow-vehicle/trailer combo. I felt a dramatic reduction in the perceived trailer-induced inputs to tow vehicle tracking and stability, i.e., sway--but I tend to define sway as a positive feedback situation that intensifies and if unchecked would cause loss of control. I didn't have that with the Reese system. What I felt was an uncomfortable awareness of the trailer perturbing the tow vehicle tracking and requiring a constant awareness of steering input to correct. What I feared was that if I felt that uncomfortable sensation a lot of the time, that loss of control might likely result under the right circumstances. Does that make sense? The Hensley did eliminate entirely that feeling. My wife fell asleep twice during a short test drive with the Hensley...something she does frequently in the truck solo, but had mysteriously never done while towing. Unscientific, but strong anecdote!!!

My pursuit of ideal sway control with the Reese resulted in ensuring that hitch weight was truly distributed--as the scale measurements confirmed. However, I found the 'better' my static weight distribution became, the greater problem developed with porpoising on the highway. This indeed may be a component of the respective trailer/truck wheelbases, but from what I have read, many RV/tow vehicle combinations will exhibit this phenomenon. It is speed dependent as well as road dependent. Concrete interstates with expansion joints are the worst!

I came to the conclusion that the balance of my stiff rear springs on the Ford F350 and tightly tensioned bars created a sea-saw sort of effect--the bars bend and load the springs, the springs rebound and unload the bars. It's a sea-saw!

This year on our trip out to Vermont with the Hensley, porpoising was only barely perceptable or absent on roads I had traveled with the Reese and had significant problems.

On the trip back, with the fresh water tank full, I noticed the rear tires of truck were a little warmer than usual. A trip to the scales confirmed that the Hensley was NOT distributing as much weight as I had with the Reese--other variations in loading prevented a definitive conclusion, but a strong suspicion it was true. I cranked the torsion bars a little tighter on the Hensley, and low and behold, the porpoising became more noticeable...but still not as bad as with the Reese.

Two other notable things I did for this trip. I changed the Ford's stock receiver hitch to a higher rated Putnam (another story entirely). And changed shocks to Bilstein's (I'll be happy to tell other Ford owners why they should consider these above any other shock I'm aware of!). Sorry for the long post!

[bryanl]

in re the Equalizer - since it is suggested the L brackets be lubed to reduce noise, it seems the sway resistance is mostly due to the spring bar receivers which have a bolt tightened spring to adjust anti sway - so I don't think they are so much dependant upon spring bar loading as the DC is. The Blue Ox or the friction bar systems would be the choice for sway reduction without worrying about spring bar loading.

The Hensley adds a bit to the distance between axles. which might influence porpoising. But what I am hearing is that most of this problem is the suspension system as a whole. Reducing the vertical trailer/tv coupling for more flexible bending helps but that means not distributing the load as much. Providing more give in the tv rear axle suspension might also help but that reduces load handling. Better shocks also seems like a good idea. And don't forget the front axles!

[bryanl]

BTW

The Hensley does not reduce inputs from the trailer, it relocates them. You can't reduce inputs without having problems with conservation of mass and energy.

The Hensley moves the latteral forces on the hitch from behind the bumper to forward of the rear axles. This means that these forces no longer attempt to yaw the tow vehicle but rather attempt to translate it (move it sideways).

Since a tow vehicle is much more resistant to sideways forces than it is to yaw, handling in response to trailer rotations about its axle is improved.

[dmac]

Leipper - I am unaware of any bolt-tightened spring in the Equal-i-zer hitch. The spring bar pivot castings are attached to the head with bolts, but they are not adjustable. The purpose of the L brackets, vs chains, is to provide friction. Both the pivots and the L brackets are greased to reduce noise, but I believe both still provide friction.

[bryanl]

Look at the instruction sheet provided with the Equalizer hitch.

Unless I misread, it recommends lubrication for the L bracket and the top of the spring bar receiver to reduce noise.

It also recommends keeping the bolt holding the spring bar receiver tight.

You don't put grease on surfaces where you want friction.

You don't have tight bolts as a pivot when you want to pivot freely, either.

The other issue that may cause confusion is that springs are not necessarily coiled wire.

check the diagram at http://www.equalizerhitch.com/home.html
and note where the arrow by "friction sway control" points. or check the faq which says "The Equal-i-zer hitch eliminates trailer sway through a friction system built directly into the hitch head."

Let me know if you think I misread the Equalizer instruction sheet and I'll go back and re-read it again.

[Pahaska]

You are correct according to my understanding of the Equalizer site and their VHS tape which I have around here somewhere. As I understand it, the Equalizer hitch works a little like the Reese Dual Cam except that the camming action is built into the hitch head rather than into the end of the bars.

Equalizer keeps trumpeting that their bars are not tapered, but they never tell you why they think that is better.