Changing out the STD 5th wheel ????

[noteven]

A “fifth wheel” or a gooseneck trailer are basically “travel trailers” handling and weight distribution wise if you connect them to a hitch point dangled way back behind the center of the drive axle(s).  They lever weight off the steer axle. And you don’t hit the coupler with your shin in the dark.

Travel trailers and rv “fivers” also have that peculiar weather vane hobby horse effect due to their little bogey wheels being located way up the chassis to keep the hitch floaty so light vehicles can tow them.

[noteven]

... 

[Moresmoke]

3 hours ago, alan0043 said:

Hi Everyone,

I have an idea that I want you guys to let me know what you think. Pro or con. I don't want this idea to get anyone hurt or killed. From what I have been reading some people would like to have the truck ride a little softer. Some of the talk was to change the amount of air in the air bags. With less air in the bags the truck could ride softer. But if this is done the correct height will not be right. Here is my idea. I am probably not the first one to think of this. Here goes. How about making a spacer for the air bag. Take the air bag loose from the truck. The spacer could be 1" to 2" thick. The spacer is attached to the truck where the air bag was attached at. Then attach the air bag to the spacer. My thought is that you won't need as much air in the air bag to get the correct ride height because you have already raised the truck 1" to 2". The air bag should be softer with less air but the ride height should be correct.

What do you guys think, pro or con
Al

You won’t have as many cubic inches of air, but you will still have the same pressure. The pressure required is the weight divided by the area of the end of the bag.

By shortening the bag, you will make the ride stiffer, as the pressure rises faster when the spring is compressed.

[phoenix2013]

15 minutes ago, Moresmoke said:

You won’t have as many cubic inches of air, but you will still have the same pressure. The pressure required is the weight divided by the area of the end of the bag.

By shortening the bag, you will make the ride stiffer, as the pressure rises faster when the spring is compressed.

Right on, less air volume, pressure goes up as is the stiffness of the air bag.

[Lance A Lott]

1 hour ago, phoenix2013 said:

Right on, less air volume, pressure goes up as is the stiffness of the air bag.

 

I had thought about building a frame between the truck rails and reinforcing the bar that the airbags sit on and adding a third bag between the two existing. But I am lazy. That would be more volume so less pressure to do the same work.

 

I still don't know how the Donvalves work as they restrict the air from leaving the bag creating more pressure in the bag as it tries to collapse when you hit a bump. However my truck rode better after I installed them, of course I had the body on as well so maybe not the best for comparing. They really work well on the cab which makes sense as the stiffening of the bag takes out that side to side slop.

[Moresmoke]

4 hours ago, Lance A Lott said:

 

I had thought about building a frame between the truck rails and reinforcing the bar that the airbags sit on and adding a third bag between the two existing. But I am lazy. That would be more volume so less pressure to do the same work.

 

I still don't know how the Donvalves work as they restrict the air from leaving the bag creating more pressure in the bag as it tries to collapse when you hit a bump. However my truck rode better after I installed them, of course I had the body on as well so maybe not the best for comparing. They really work well on the cab which makes sense as the stiffening of the bag takes out that side to side slop.

The Donvel valves work to slow the transfer of air from bag to bag. Should be most noticeable on the cab as the bags are relatively small, and the air line can transfer some air side to side.

Donvel valves do the opposite of a ping tank, which softens the ride.  The purpose of “ping” tanks is to increase the total air volume in the system. The problem is you need to have ports on the airbag that are large enough to move a substantial amount of air between the spring and the tank. The air bags on my Volvo only have 1/4 npt ports. 

I’ve driven some trucks with a heavy Neway air ride that is designed for off road use.  They have awesome articulation, but don’t really resist side to side sway that well.  These trucks were built with a leveling valve on each side. No air transfer side to side at all.  Down side was that once the valves wore some, the truck never sat level.

[Lance A Lott]

More smoke thank you one of those duh moments .

[alan0043]

19 hours ago, phoenix2013 said:

Right on, less air volume, pressure goes up as is the stiffness of the air bag.

Sounds like the ideal gas law.

[phoenix2013]

On 11/4/2018 at 7:58 AM, alan0043 said:

Sounds like the ideal gas law.

Those pesky air molecules only love the laws of physics and don't care much for opinions or wishful thinking.

Approximately twice the air volume produces approximately twice the weight rating.

Airbags are designed for maximum pressure of 100 psi and are rated at that pressure for maximum weight to be carrying. That weight (and pressure) can be exceeded by twice that amount (200 psi) without bursting the bag. It's known as a jounce rating. The airbag will burst above that pressure and weight but neither Goodyear nor Firestone tell you what that pressure is. You can see that note at the bottom of the next picture

Also note how linear the response of an airbag is over its operational range from the lowest to the maximum pressure and from the minimum to the maximum weight. That makes it an ideal suspension element that's both linear and variable. Conventional springs are also linear but they are not variable. F-150 has a half ton springs, F-250 has a 3/4 ton springs, F-350 has 1 ton springs and that's it. That's why the commercial trucking industry uses pretty much 100% air springs in suspensions, where class 8 truck can go from 30,000 pounds to 80,000 pounds total weight on the same suspension in the truck and trailer.

So why is suspension being linear and variable important. Suspension technology is not new it's been around since royal coaches  and stage coaches going back to the 1800's. Suspensions are supposed to smooth out the roughness of the road and not transfer it to the passengers or the cargo. You would not be impressed with your car if it bottomed out on every crease in the road and you would not be impressed with your car if it bottomed out on every crease in the road when you took your 300 pound uncle for a ride. Two examples illustrating why linearity is important over the suspension's range. Since we are on the subject it's also important to consider what happens when suspension says "I'm done" and bottoms out. Typically what's added are shock absorbers which slow down the suspension's race to the bottom and then rubber or polyurethane bumps to stop that metal to metal jarring when suspension does bottom out.There is a hitch out there that has been marketed as the next "Holy Grail" because it does not use airbags, "because  air bags are bad". "They move too much, they need frequent replacement, which is costly when required (none replaced by me in 13 years)". Being an engineer I'm always skeptical when marketing types, claim a direct connection to the Almighty and the Holy Grail,. I evaluate things and I test. It just happens that I was in the middle of incorporating polyurethane bumps as shock absorbers and bump stops and researching that industry and it's products. The reason I was looking at these because that material exhibits a perfect behavior as an end of the motion stop and a final shock absorber.

 

Here's a more detailed look at its response to force.

The straight line you see in the drawing is linear, that's the way that a similar airbag would perform. The bottom line is exponential and the way this particular bump performs. Note a couple critical differences and peculiarities. The bump is rated for 2,000 pounds of force over a range of travel of 4.5 inches. Note that at 2 inches of travel the airbag would be resisting the motion with 1,000 pounds of force, the bump 150 pounds. At 3.5 inches of travel, airbag is at 1,600 pounds, and  the bump at 400 pounds. Not until you get to the last half inch of travel do you see an accelerated response from the bump, building up a resistance of 1,200 pounds over that short distance. Perfect response for an end of the travel device, lousy response for a suspension device. As an engineer I don't just read specs, I test and I figured the best comparison would be airbags vs. bumps. Couple of these were mounted on the  hitch stop plates to be squeezed by the air bags. 10,000 pounds of pressure at 100 psi and since they are linear 1,000 pounds per 10 psi.

 

I had a pressure gauge attached to the airbags to see how much force was being generated, at the physical compression you see it read about 15 psi, which would have indicated 1,500 pounds of force between the two bumps or around 750 pounds each at this substantial compression. The air gauges are not that accurate at the low readings but this seemed to follow what you'd expect on their exponential curve when squeezed that much.

So these devices don't do much for you throughout most of their travel until compressed almost to the end of their travel range. Which makes sense since many of them are required in the hitch in question. The other indication is the requirement that the hitch head is set up at 49 inches (not 47 industry standard). Again, an indication that 2 inches of travel has to be "sacrificed" in order to get out of the non-operational range and closer to the end of the travel range.

Another, all encompassing "opinion" was offered that air hitches "move too much".  Since we are into "opinions" I have my own. "That system of suspension does not move enough". Indeed I asked those who had a camera on those and they didn't see much movement except on potholes and such.

Let's continue with a little bit more  "hitch" education.

See that little note that says, 6.7" MAX EXTENDED HT." This is a critical bit of engineering information provided by manufacturers and you have to design your product to limit the bag travel so that this height is not exceeded (under any pressure). Otherwise the airbags will blow up, like these.

Why did they blow up? Because once the fifth was hit by a Greyhound bus and totaled.

The hitch was the only thing keeping the fifth from going into the truck.

Note that the stop plates (1/4 inch thick 11 inches long) did not completely retain the hitch swivel plate, which managed to go past the plates, resulting in blown airbags and did not prevent one of the shafts from shearing. The re-designed stop plates (3/8 thick) were again in action on the same model hitch seven years later.

Absolutely no damage to the hitch (which I completely examined and took apart)

Bags were fine, truck was fine, the fifth was totaled. Nothing separated even thought the coach was hanging in the ditch and truck's rear end was up off the ground  on one side. Note that the coach was trying to flip the platform in the hitch and go forward but the stop plates (this time) held it contained. The stop plates in hitches serve two functions. They limit the travel of the airbags below the design maximum height and also to prevent the hitch platform from flipping over and going forward in an accident and coming apart. Having had close experience with those "events" I've developed certain "skepticism"  with the containment methods I have seen on other products.

 

 

 

 

 

[Jack Mayer]

Henry's post above is the very reason I only use an air ride hitch on my personal equipment. I could use anything. But the air ride in COMBINATION with "air cell" acting as a bump dampener, is technically the best combo I have seen to date for a suspension hitch. The data backs that statement up.

[Jim & Wilma]

13 minutes ago, Jack Mayer said:

Henry's post above is the very reason I only use an air ride hitch on my personal equipment.

Agree Jack and thanks Henry for putting together some of the design basis details of air suspension hitches for folks to consider when they decide on their hitch.  I value data, analysis, testing and application feedback that helps us make an informed decision on the equipment we use.

[Jack Mayer]

3 minutes ago, Jim & Wilma said:

Agree Jack and thanks Henry for putting together some of the design basis details of air suspension hitches for folks to consider when they decide on their hitch.  I value data, analysis, testing and application feedback that helps us make an informed decision on the equipment we use.

There are a lot of "opinions" out there. But in many cases, they are not based on any facts or data. I also prefer to use at least "some" data to form decisions.  To some, having less than an optimal solution is fine. I prefer to chase the best solution to a problem.  Sometimes there is not a perfect solution.

[jenandjon]

Let me see if I am understanding this correctly. You are basically combining the air cell technology of the comfort ride and the air bag design of the Trailer Saver to create an even better ride?

[phoenix2013]

On 11/8/2018 at 7:27 AM, jenandjon said:

Let me see if I am understanding this correctly. You are basically combining the air cell technology of the comfort ride and the air bag design of the Trailer Saver to create an even better ride?

jenandjohn, I am not ignoring your question, I am in a process of formulating a more "thorough" answer. That's why I like this forum, there is a lot of experience, wisdom and curiosity here, three pages on this thread alone sort of prove that point. For instance I learned something new here again.

Interesting new products I didn't know about. Height adjustability is nice, but what I find interesting is that they incorporated torsion bar springs in the hinges to provide up and down cushioning. I didn't see any specs of the range of tongue weight that these are supposed to be effective with, perhaps someone can enlighten me on that. Last time I played with something similar was when I installed one of these in a receiver hitch.

This one was using an air bag as a cushioning element.

 

[DesertMiner]

This Might help.... 

https://genyhitch.com/product-category/boss-torsion-flex-drop-hitches/

[Lance A Lott]

Phoenix I think they have a units for up 3000 lb  and like 25k they also make gooseneck hitches. The people I have talked to love them. The problem would be with adjustability, there is none, still they give and that is a lot better than a solid hitch. You can use them with wheight distribution as well although I have not talked to anyone who has. The Shocker hitch has a airbag and a bump of some sort. I see DesertMiner has posted a link.

[phoenix2013]

Fascinating, thanks for the link DesertMiner. As an engineer I like to see innovating products. I only see in their specs the GVW numbers for the trailers they like to see behind these couplers and not the tongue weight limits. Torsion bars springs are pretty robust but not limitless and the rubber sections in this assembly would be pretty short further limiting the range of tongue weights you can put on them and not ruin them. Why is it that the hitch manufacturers and trailer manufacturers don't like to talk about pin weight or tongue weights. It shouldn't be a taboo and they shouldn't  claim ignorance about the subject.

I had a torsion bar suspension on my first fifth I bought new from Kropf manufacturing in the early 80's. This thing pulled like a dream and on long trips everyone, yours truly, wife and kids, loved riding (and sleeping) back there in the fifth. The only downside is that these are limited only to two axles and not three since there is no load sharing like there is with springs and you can overload them in three axle setups.

Dexter still makes them and for the curious here's the link 

I saw that Lippert offers these also and these jackasses can ruin anything they lay their hands on, but on closer examinations Lippert axles look very much like Dexter's so maybe these are one and same.

I did noticed that genyhitch  makes  gooseneck adapters with torsion bars springs.  I agree that there is no adjustability but they do offer several models and I'm assuming one can find one that will work for one's trailer. But that brings us back to my earlier point that knowing the range of tongue weights on different models is a critical bit of information which they should provide. It shouldn't be up to the customer to guess which one will work, buy it and see if it works. 

But, I love companies that engineer and innovate things, make them and sell them.

[noteven]

Our nearby little city has a traffic lights crossroad intersection of the major highway and a busy commercial avenue. It’s one of those pieces of road the maintenance superintendents that draw up the pothole and ruts in pavement repair orders must never ever drive on. A great place to dislodge snow, ice, or dried mud off your rig. Downrange the shoulder is littered with air brake dust shields, pieces of springs, the odd muffler etc. 

Anyway I’m there waiting to turn and a new F-150 towing a floor over the wheels enclosed trailer (aka snowmobile trailer) about a 26ft? turns across in front of me. As he traverses the holes and ruts I note his trailer is a rocking and teeter tottering totally independent of the truck. 

As he passed to my left I peered down from my high vantage point in the Kenworth there it was! A Gen Y hitch! My first sighting in the wild!  I should get a life...

The truck and trailer were moving gracefully independent of each other, looked like about 3”.  Trailer looked happy. 

They look like a nice uncomplicated solution. I would think it is ideal if your tongue weights are fixed but it is going to give some even at light weight. 

I have an AirSafe like Phoenix pictured above. It is heavy to wrassel with.  It works nice. It is very adjustable for lighter tongue weight. Weight distribution works fine. You need to fiddle with the psi as a bit you change temperature and altitude. You learn right away not to unhitching without deflating the suspension in it. I do like to experiment with “the Hard Way” so I did it twice just to make sure that is the wrong way. 

[Lance A Lott]

It takes some searching on there site look under options 10k/1100 tongue 16k/1700 tongue 21k/2400 tongue.  Gooseneck 16k/3000 tongue 25k/5500 tongue 30k/7000 tongue. my trailer is 3600 tongue so I talked to them and they said the 3k would work or the 5k would work but they said I would have diminished travel with both as one would be compressed more than optimal the other would resit more than optimal. they are thinking about a 4k version. Mr Truck has a video but I think they put a 7k tongue weight one on a trailer that was only 10k it didn't look like it did much.

My trailer has the torsion axles and it worked well with a full load of horses and hay and the camper ready for 2 weeks of dry camping but when we stopped taking the kids horses and all there stuff it road a little harsh. This year i installed a kelderman air ride kit so it is now a hybrid. We have a camera in the horse compartment and all we see now is a ripple in there muscles going over a railroad track. So i think the combination works well.

I have a Cody Cushion on the HDT and it seams to work but I have wondered about adding a Gen y or a Shocker to the gooseneck. any one use both a air fifth wheel and air pinbox?

 https://www.google.com/search?q=cody+cushion+hitch&tbm=isch&source=iu&ictx=1&fir=uvujhUdWIFB_eM%3A%2C4yARWOSgT2BYuM%2C_&usg=AI4_-kRC6umEVdVERq-LfaheyuI6ERvNKA&sa=X&ved=2ahUKEwjKnsK7psreAhUQZd8KHRRnAHoQ9QEwD3oECAUQBg#imgrc=uvujhUdWIFB_eM:

 

https://www.google.com/search?q=shocker+gooseneck+hitch+for+sale&tbm=isch&source=iu&ictx=1&fir=RZwmUV9s-OnFSM%3A%2CFCJs-FXmkYe9uM%2C_&usg=AI4_-kQ6ig2pUE8kAmcilZsDLSJqMItPnQ&sa=X&ved=2ahUKEwjPl4yKp8reAhWCnOAKHZM4BEIQ9QEwE3oECAEQCg#imgrc=RZwmUV9s-OnFSM:

[dan412]

Is there a way to use a air spring that carries half the weight as the stock ones. If you have two axles that carry 34000 LBS could you use air springs that carry 17000 LBS but have the same ride height.

[Mark and Dale Bruss]

33 minutes ago, dan412 said:

Is there a way to use a air spring that carries half the weight as the stock ones. If you have two axles that carry 34000 LBS could you use air springs that carry 17000 LBS but have the same ride height.

It is obvious that you do not understand how the axle air springs.  They change the air pressure to keep the frame level to the ground, that is the purpose of the leveling valve.

[Lance A Lott]

If you went the other way say 50k air spring it would be a softer ride, but your handling would probably suffer. A smaller, 17k bag, would have to be very hard, high psi, to suport the load at the same hight. Kind of like a bouncy house it will hold a lot of kids with just a fan supplying the air but very sloppy and no support when the load shifts.

[dan412]

10 hours ago, Lance A Lott said:

If you went the other way say 50k air spring it would be a softer ride, but your handling would probably suffer. A smaller, 17k bag, would have to be very hard, high psi, to suport the load at the same hight. Kind of like a bouncy house it will hold a lot of kids with just a fan supplying the air but very sloppy and no support when the load shifts.

So you are saying that in order to hold up 17000 LBS I would need a air bag that is made to hold up 50000 LBS. that doesn't make sense.

[Lance A Lott]

1 hour ago, dan412 said:

So you are saying that in order to hold up 17000 LBS I would need a air bag that is made to hold up 50000 LBS. that doesn't make sense.

No that is not what I am saying. If you want a softer ride, and have air springs, then you would go bigger with the bag, or add more bags, so that it requires less psi to do the same work as the smaller bag. A larger volume of captive air will hold up the same weight with less psi thus having more flex. But a softer ride makes for a sloppier handling vehicle. So you have to be careful with how much you change things.  This is one of the reasons why you insulate the trailer from the truck.  

[noteven]

For all your air suspension reading pleasure:

Firestone Air Suspension Design and Engineering Guide