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Building a 5th Wheel Air Ride Hitch


bmzero

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I'm considering building my own 5th wheel air hitch.

 

First off, I acknowledge the massive responsibility in making this statement. Not only does the hitch put my family and myself at risk, but it also puts others on the road at risk. I do understand that.

 

I'm leaning toward a four-arm (four pivot points) design rather than a two arm design (two pivot points) such as the McCall - http://www.google.com/patents/US6170849. I believe the head staying level and below the "tipping" point of the arms is beneficial in quite a few ways.

 

There are three main reasons I want to build a hitch:

  1. I already have two fifth wheel hitches at the shop that I won't be using after the HDT is finished - a B&W Companion currently installed on my F450 and a PullRite Super Glide currently collecting dust/rust.
  2. I think the ability to have the hitch position slide forward or rearward could be beneficial. For example, when in the "driving" position, I would like the trailer to sit as close to the cab/Smart cart as possible. When in "my neighborhood is very tight" mode, I would like the pivot point to move as far rearward as possible. I'm concerned about getting my setup into my neighborhood. Having this movement would definitely be helpful. It might also be helpful when pulling a longer trailer. You could keep it as short as possible when on the highway and lengthen it back out to make tight maneuvers (obviously this would require a mechanical lockout in both positions).
  3. I would like the ability to remove the 5th wheel component and swap in a gooseneck ball. Using the B&W Companion hitch would be perfect for this.

I haven't seen any designs on the market that accommodate those traits. Granted, there may be some very good reasons those traits aren't met, but I'm curious as to your thoughts.

 

Also, I think the ET Hitch is an amazing work of art, so I would not be trying to make a "better" hitch - just a hitch that meets different requirements.

 

How much more maneuverability do you think could be achieved by sliding the hitch a few feet. For the purposes of this conversation, let's assume I could securely move it three feet.

 

Thoughts?

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One way to find out would be to compare the differences in trailer tracking of similar length trailers (kingpin/ball to axle centers) on a 5th wheel/gooseneck to bumper pull trailer.

 

Every designer/engineer has had to deal with building their First Generation whatever. As long as you Truly have the skills to properly build something stronger than required I have no qualms from you building your own design. Quality materials and the skill to execute the properly designed product are your only requirements.

 

Even with the ET there are ways to improve on the design. Are they required? Absolutely not, but for me there are a couple of things I would tweak but I'm sure it's only because I like doing things like that. Heck, I'm sure Henry always has some neurons firing on all cylinders on what he can do next to improve on everything he ever touches. That's just the way our brains are wired and I'm sure that includes 88% of the people on this message board.

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I'm considering building my own 5th wheel air hitch.

 

First off, I acknowledge the massive responsibility in making this statement. Not only does the hitch put my family and myself at risk, but it also puts others on the road at risk. I do understand that.

 

I'm leaning toward a four-arm (four pivot points) design rather than a two arm design (two pivot points) such as the McCall - http://www.google.com/patents/US6170849. I believe the head staying level and below the "tipping" point of the arms is beneficial in quite a few ways.

 

There are three main reasons I want to build a hitch:

  • I already have two fifth wheel hitches at the shop that I won't be using after the HDT is finished - a B&W Companion currently installed on my F450 and a PullRite Super Glide currently collecting dust/rust.
  • I think the ability to have the hitch position slide forward or rearward could be beneficial. For example, when in the "driving" position, I would like the trailer to sit as close to the cab/Smart cart as possible. When in "my neighborhood is very tight" mode, I would like the pivot point to move as far rearward as possible. I'm concerned about getting my setup into my neighborhood. Having this movement would definitely be helpful. It might also be helpful when pulling a longer trailer. You could keep it as short as possible when on the highway and lengthen it back out to make tight maneuvers (obviously this would require a mechanical lockout in both positions).
  • I would like the ability to remove the 5th wheel component and swap in a gooseneck ball. Using the B&W Companion hitch would be perfect for this.
I haven't seen any designs on the market that accommodate those traits. Granted, there may be some very good reasons those traits aren't met, but I'm curious as to your thoughts.

 

Also, I think the ET Hitch is an amazing work of art, so I would not be trying to make a "better" hitch - just a hitch that meets different requirements.

 

How much more maneuverability do you think could be achieved by sliding the hitch a few feet. For the purposes of this conversation, let's assume I could securely move it three feet.

 

Thoughts?

1. Might be better to sell those and use the money to buy an ET.

2. The sliding hitch is not actually part of the hitch. Using sliding rails that the hitch plate is mounted to is better. Two people come to mind, wrknver (Vern) and J&V I believe have sliding hitches on their HDT's.

3. You do not want a gooseneck ball in a pivoting head. The ET does have an unadvertised version with a gooseneck ball in addition to the 5th wheel hitch.

 

Otherwise it does not hurt to try to build but testing the failure point could.

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I don't think you are going to be able to get 3 feet. Think about the overhang of the trailer. Even with the trailer sucked up so that you are shorter you still have to be able to turn.

 

The only truck that I can think of with a sliding hitch is J&V. Do a search on his build and photos. I think he used the sliding mechanism from a trailer tandems as the basis for his. Basically the hitch sits in a sled and sled can be moved forward/back. I think he has between 12"~18" of travel.

 

On my truck I added 6' of frame to the existing frame and did not move my axles. My hitch sits at the end of the frame rails. For me the position works very well. Moving forward the trailer tracks the truck very closely in turns. In backing the distance from the axle to the hitch makes the trailer very responsive when turning. In 5 years/60k miles I personally have not had a situation where moving the hitch would benefit me.

 

In the end if the goal of having a sliding hitch is just for maneuverability you will find that you will spend a lot of time, energy and money for a feature you will very rarely need in my opinion. In J&Vs case the forward position is needed for loading/unloading the vehicle (gate/hitch clearance) but he can not travel in that position because of clearance issues with his box/garage and the trailer cap in turns.

 

I know maneuverability with a HDT was a big fear of mine in the beginning. I think you will find most initially have similar fears. It is hard to believe how maneuverable these trucks really are until you get a little experience behind the wheel. Having the hitch behind the axels instead of over the axles makes a huge difference.

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Reread Star Dreamers #2 point. Again. And yet again. Many, not all, commercial hitches come on a slide plate. With a button on the dash to release the 'dogs' and allow it to slide.

 

Having said that, I have 2 in the backyard. Both look like they have never been slid while in commercial service.

 

Your MDT will turn on the inside of the turning radius of the 450, just saying.

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1. Might be better to sell those and use the money to buy an ET.

2. The sliding hitch is not actually part of the hitch. Using sliding rails that the hitch plate is mounted to is better. Two people come to mind, wrknver (Vern) and J&V I believe have sliding hitches on their HDT's.

3. You do not want a gooseneck ball in a pivoting head. The ET does have an unadvertised version with a gooseneck ball in addition to the 5th wheel hitch.

 

Otherwise it does not hurt to try to build but testing the failure point could.

 

1. You might be right on that one. I'm definitely open to that being a possibility.

2. That was my intention. I'll check out the trucks you mentioned. Thanks for the reference.

3. The entire B&W Companion setup (pictured below) would be removed and replaced with a ball only, so there wouldn't be a pivoting head for the ball, but the ball would still be mounted on the air supported platform.

 

companion_3500_on_turnoverball.jpg

 

I appreciate the feedback.

 

A few more points:

  1. I have no desire to sell this hitch commercially. I'm a web designer by trade, so metal fabrication is like therapy for me. At the point when it becomes a job, it loses all appeal to me. I have been through that with race car fabrication already.
  2. I based my 3' comment off of the distance from the rear bumper that my B&W hitch is mounted in the F450. I have seen quite a few hauler beds on HDT's where the hitch is mounted at the very rear of the bed. I'll do some measurements when I get back in town, to make sure, but I'm pretty sure there is quite a bit more room than 18" there. I could be wrong, though.
  3. The B&W hitch looks like it would come close to fitting well between the frame rails, taking some of the hard part (and risk) of this project out of the equation. I'll verify this when I get back home.
  4. Due to the liability and risk involved, I would probably draw this up in Solidworks before striking an arc to metal. That way, I can accurately check forces involved. It would also allow me to have everything laser cut and bent before it got here. Solidworks also does self-jigging very well now making the assembly process much more accurate for one off assemblies.

Edit note - after looking at the photo of the B&W above, it looks a high mounting surface for the plate. I'll have to check that first.

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Hmmm. Me thinks (dangerous) that just using an E-T with the ball attachment would be simplest, and in the long run, cheapest. If maneuverability is a prime concern, I'd bet dollars v. doughnuts that you'll be better off with the HDT v. the F-450 even with a stationary hitch.

 

But, have you bought any doughnuts lately? That old saying is getting close to being out dated. :o

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How about giving us some ideas about the truck bed.

Are you going to single the truck out or leave it tandem?

Planning on carrying a car or toys on the bed or?

Tucking the trailer up behind the sleeper generally won't gain you anything with these HDT's. In our application we're barely using the trucks capabilities.

From my research, moving the hitch 2-4ft behind the rear most axle gives the 5th wheel rv the same tracking characteristics as a typical bumper pull trailer.

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How about giving us some ideas about the truck bed.

Are you going to single the truck out or leave it tandem?

Planning on carrying a car or toys on the bed or?

Tucking the trailer up behind the sleeper generally won't gain you anything with these HDT's. In our application we're barely using the trucks capabilities.

From my research, moving the hitch 2-4ft behind the rear most axle gives the 5th wheel rv the same tracking characteristics as a typical bumper pull trailer.

 

Yes, I will single the truck mid and it will have a Smart car platform on it and a hauler bed. For the next few years, that platform will carry around a second Polaris RZR as I'm limited to one within the current toy hauler.

 

You're probably right about the hitch sliding not making that much of a difference. That's a secondary concern at this point. I'm more interested in designing the hitch system than the slide system.

 

I see a lot of comments about the turning radius of the F450 vs the 730. For 2008-2010, the 4WD F450's were equipped with a Dana "Super" 60. The extra width of this axle allows more angle of the front wheels, allowing for a much tighter turning radius. My 730, in its current length/dual drive axle configuration won't hold a candle to the F450 truck to truck (no trailer). There's no doubt that will change when I single the 730, but I would be very surprised if it out maneuvered the F450. Granted, with a trailer on it and the hitch moved behind the rear axle, it will probably do better than the F450.

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A Sliding air ride platform the B&W sits on would be doable. 1st off, I built my own as well, because my truck already had a heavy rear bumper frame with weights on it I didn't want to cut out. My truck is fairly short, so there wasn't a lot of room behind the rear pumpkin to fit a "box" like the E-T or others--mine is a "open frame" approach. Clearance may be the biggest concern I think you would have to deal with. The height of the hitch head isn't all that much above the frame rails of the truck--to fit the air ride and slide assm under the B&W without interfering with you axle may be --Tricky. Now if you have a long tail and want to slide in that tail--that should work fine (IIRC, this is what you are doing right?)

I think your on to something to make a gooseneck ball air ride assm, and then set the B/W on it just like on a PU. I'm a farmer, B&W makes a NICE hitch design. With your obvious skills, should be no problem. Also, you aren't really making your own hitch, just the frame it attaches to. Make sure it is "caged" so it can't flip up and over in an accident, and pins solidly like a sliding commercial.

From Experience, moving the hitch back at least 2-3' behind the axle makes a HUGE difference in backing into tight spots. Going back further---may be better or it might actually be too much?? I can't say.

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Ah - I don't see anything about longer or more angle. It is still a pickup (yes a bit beefed up) and the width is going to be - cab wide - about 6' and the angle is going to be about 35*. With the (on the Volvo anyway) 50* degree cut on the front, it does turn inside our F350 CC. Dug holes in the grass 'proving' it.

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Ah - I don't see anything about longer or more angle. It is still a pickup (yes a bit beefed up) and the width is going to be - cab wide - about 6' and the angle is going to be about 35*. With the (on the Volvo anyway) 50* degree cut on the front, it does turn inside our F350 CC. Dug holes in the grass 'proving' it.

 

http://www.thedieselstop.com/forums/f152/f-450-wide-track-front-end-why-not-265405/

 

http://www.ford-trucks.com/forums/746138-wide-track-turning-advantage.html

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I'm considering building my own 5th wheel air hitch.

 

First off, I acknowledge the massive responsibility in making this statement. Not only does the hitch put my family and myself at risk, but it also puts others on the road at risk. I do understand that.

 

I'm leaning toward a four-arm (four pivot points) design rather than a two arm design (two pivot points) such as the McCall - http://www.google.com/patents/US6170849. I believe the head staying level and below the "tipping" point of the arms is beneficial in quite a few ways.

 

There are three main reasons I want to build a hitch:

  1. I already have two fifth wheel hitches at the shop that I won't be using after the HDT is finished - a B&W Companion currently installed on my F450 and a PullRite Super Glide currently collecting dust/rust. No harm in re-utilizing something you already have, particularly if it's collecting dust. I did it when I had a "need" for an air hitch by modifying a "hard" Reese which came with the truck. The "performance" of this "conversion" was in the category of "better than nothing", but I learned a lot and the trailer was relatively light, 12,000 lbs loaded.

2332444410096176628gbrHjC_fs.jpg

2. I think the ability to have the hitch position slide forward or rearward could be beneficial. For example, when in the "driving" position, I would like the trailer to sit as close to the cab/Smart cart as possible. When in "my neighborhood is very tight" mode, I would like the pivot point to move as far rearward as possible. I'm concerned about getting my setup into my neighborhood. Having this movement would definitely be helpful. It might also be helpful when pulling a longer trailer. You could keep it as short as possible when on the highway and lengthen it back out to make tight maneuvers (obviously this would require a mechanical lockout in both positions). The further back behind the axle you can get the pivot point the better it will maneuver in "tight spots". Mine is about 5 feet behind the axle (permanently) and when backing I have to use very small movements of the steering wheel not to overcompensate. I'm not sure what the utility of being able to move the hitch buys you? J&V on the forum has a movable ET (2 positions), perhaps he can "pipe in" and offer his wisdom, why he has it and how often he calls upon this feature. Making sure that the locking scheme is bullet proof would be paramount, but it can be done.

 

3. I would like the ability to remove the 5th wheel component and swap in a gooseneck ball. Using the B&W Companion hitch would be perfect for this. I haven't seen any designs on the market that accommodate those traits. Granted, there may be some very good reasons those traits aren't met, but I'm curious as to your thoughts.

Swapping entire hitches is also doable but it but it can get tiresome pretty quick, there are options for having both at the same time.

2052926400096176628IDtjjE_fs.jpg

 

 

Also, I think the ET Hitch is an amazing work of art, so I would not be trying to make a "better" hitch - just a hitch that meets different requirements. Thank you for the compliment, a cautionary note from one engineer (with SolidWorks) to another engineer (with SolidWorks), anything can be reverse engineered, but a dual pivot concept, beyond paper design, is several magnitudes more difficult in implementation vs. the theory. I was so disgusted with my $6,500 prototype that I absolutely refused to even consider building another (copy) for over a year. What is more important, there were gotchas and stresses built into the prototype that resulted in the failure of one of the shafts while pulling, it was exciting, but not catastrophic because of the redundancy in the system. The prototype is still in service, but it has been rebuilt couple of times to incorporate essential "improvements". The manufacturing processes involved to make this thing come together and work, border on "black magic". Several of the owners witnessed these processes, including one with PhD in mechanical engineering, perhaps he can comment.

 

How much more maneuverability do you think could be achieved by sliding the hitch a few feet. For the purposes of this conversation, let's assume I could securely move it three feet.

 

Thoughts?

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Henry, out of curiosity, was your prototype hitch designed in Solidworks first or did you get it into Solidworks after your hard prototypes? I appreciate the detailed feedback.

 

One of the benefits of building the platform using the B&W components is the ability to have both hitch types supported by air. I haven't see any dual-hitch setups where both were air supported.

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I am thinking of modifying my hitch to accommodate a bolt on 5th wheel plate. Might be able to weld one up and bolt it onto the plate my ball is attached to. Don't think I will have a problem with the hitch strength. Might give some ideas for building you own

 

 

That definitely looks like a beefy setup. Looks strong to me.

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Wow, that really makes me want to build my own. I really appreciate you sharing all of those photos. I also like seeing your son in there with you. That's one of the main reasons I want to build one is to have my son see a project like the hitch, and the HDT in general, evolve into something we spend a bunch of time with. I think my kids' generation is going to miss out on people building their own "stuff".

 

I like the radius bends on your perimeter plate. That's a nice, clean, touch.

 

Did you draw that up in CAD or share dimensions of each part with a cutting/bending shop?

 

Great job. Thanks again for posting.

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