Homemade receiver hitch???

[zuhl555]

Okay, first off I know that everyone reading this is gonna have a cow about this but I wanted to get some opinions.

To give some background, no one in my family has ever used a receiver hitch. We usually buy or build a serious heavy duty bumper for the work trucks and pull with that. And I have never known of any problems with this and we have pulled more weight down that road than I even care to calculate. (2 tandem trailers with six 6-ft diameter round hay bales on it - bumper hitched - not fitfth wheel).

Anyway, I don't really want to replace my bumper becasue I kinda like it, but as a mechanical engineer looking at the class 4 hitches on the internet, I am not impressed at all by what you are getting for the price. There really is nothing to them.

Anyway, I am considering running some calculations on some steel tubing and making up a design in Pro/Engineer to build one of my own. I might even import it into a finite element program to determine deformation under load and find the absolute failur point of the assembly. I am pretty sure I could build one twice as stout as a class IV for about a quarter of the cost. Has anyone ever attempted or heard of this. Are there any special consideratoins that I need to keep in mind? Any laws against this? That would seem dumb because there are no laws against homemade bumpers.

I plan to use at 1/4-in to 3/8-in thick rectangular tubing for the cross member and at least some 3/8-in angle for the frame mount. Anyway, that all depends on what my calcualtions come out to. Grade 8 bolts to mount it.

 

[ygmn]

Dayum......a bored ME......

I could design one....but i do not have welding machine nor scrap steel lieing around......

You can buy a receiver hitch for under 200 at most places...and well even though steel costs about 50 cent per pound....they usually make ya buy large quanitites....

So say you want to use 2x2 square tube...you would have to buy a 20' stick...and well then not cost effective....

I do no think you will need FEA to design one as it is a basic static problem......and if you did do FEA what would you assume the frame is where you attach? It would deflect as well....which is hard to model without knowing the grade steel and its end restraints.....

Good luck if you do design....and build.....

I would be interested in your DWG drawings to look at.....

 

[zuhl555]

Agreed that FEA is not need to solve basic problem. It would have to be modelled as a free body with pivotting mounts, otherwise it would be statically indeterminate. Simple beam deflection could be used based on the tubings moment of inertia. FEA would be cool to see though.

I also agree that 20 ft sections would be cost prohibitive. But the longest section I would need is the center crossmember and that is only 39-in I believe. I think I could probably find that in one of the scrap piles of an iron yard around here.

For the main cross member I was actually thinking 4x6 tubing. Then in the center, notch for the 2x2 and weld on both ends with 70 or 80 series rods. The width of the cross member would help preduce flexure of the 2x2 receiver tube.

I have also considered just using a big honkin-@$$ piece of channel about 10 to 12 in wide with a 2-3 inch flange (Thickness = TBD). This could fit up all the way across the span and bolt directly to the frame from underneath. I could notch a hole in the center at the flange and weld the 2x2 tubing all the way down its width. This would look kinda cheapo, but I bet it would be strong as heck and once painted, no one would know the difference.

 

[ygmn]

IF you want super strong.....then get I beam and box it in....and make bolt to chassis...then slic through beam and weld in the 2x2....

I guess my point....is they make em plenty strong enough....but a project is always fun.....

and then if you make it with drains you could get it CHROME dipped....

I have 2002 cladded so I pretty much am stuck....and I like the stock one..,..

I have always prefered the look of structural tubular members to beam and channel......

Have fun

 

[zuhl555]

Thanks. On the Ibeam do you mean box it in on the ends or the sides - longways? Since the web of the Ibeam provides the most strength and not the Flanges, I would think th difference between it and c- channel would be small. But I do agree that channel does not look near as good as tubular steel. But, then again, who is gonna see it. And on the other hand, if it is gonna be done it may as well be done right. Thanks for humoring me on this project. It has been good talking with you. Like you said, it is mostly for fun. And somewhat to prove it can be done.

 

[ygmn]

Actual for bending the Flanges are the part which increase the section modulus so much......not the web...hence the web can be so thin.....

Lay it flat....with web horizontal....then add steel similar to web and weld onto ends of flange....so it will look like tube structure when done....

Kinda like this |I| but rolled on side.....then when trailer forces will be induce bending into the structure the flanges will take load.....

But if you look at actual loads from trailering...the limit of the AVY....the round tube provided does the trick.....

Problems arise from too much tongue weight as it makes the front end of truck light and you loose steering and braking power......hence the need for load leveling hitch....

Good Luck

 

[zuhl555]

Cool. I will keep all that in mind. All of our trailers that can carry very heavy loads have brakes on them. I just need ot hook up some trailer brakes on the Av and an 8-pt connector. But that would be rare for me to pull stuff that heavy, I would use my dads 3/4 pickup instead.

Just out of curiosity, has anyone ever hooked up a gooseneck or fifth wheel hitch in the bed of an Av? I would think not on a 1500, but who knows? I have no intention or desire to do this, just curious.

 

[ShapeShifter]

I do no think you will need FEA to design one as it is a basic static problem......and if you did do FEA what would you assume the frame is where you attach? It would deflect as well....which is hard to model without knowing the grade steel and its end restraints.....

Agreed that FEA is not need to solve basic problem. It would have to be modelled as a free body with pivotting mounts, otherwise it would be statically indeterminate. Simple beam deflection could be used based on the tubings moment of inertia. FEA would be cool to see though.

Hey, ygmn! Who's getting all geeky around here now?

-- SS

 

[ygmn]

I do no think you will need FEA to design one as it is a basic static problem......and if you did do FEA what would you assume the frame is where you attach? It would deflect as well....which is hard to model without knowing the grade steel and its end restraints.....

Agreed that FEA is not need to solve basic problem. It would have to be modelled as a free body with pivotting mounts, otherwise it would be statically indeterminate. Simple beam deflection could be used based on the tubings moment of inertia. FEA would be cool to see though.

Hey, ygmn! Who's getting all geeky around here now?

-- SS

Hey man....structural engineer was a thing I did a few years ago....and well it stays in the blood....


Zuhl....check in this section on towing for gooseneck towing.....as GM states in MANUAL....do not do it...but I think one is trying....

Gm says no due to where axle is in bed, tall bed sides, sail area getting hit.....

Good luck...

SS Von Mises was a smart man....... fb = M*c/I = M/s

fb<=Fb Fb=.6Fy for mostshapes depending on flange width to thickness ratios.....

AISC rocks baby

 

[brmiller]

Hey, ygmn! Who's getting all geeky around here now?

Yeah, and I get accused of this daily...

Brendan

 

[zuhl555]

Glad to meet you guys. It is good to get a cbance to geek out on occasion. Hardly get to use all that schooling when I am at work. Take care.

Dustin

 

[Mdz66]

Hey with the I beam and boxing it you could make your steps where ever you want them instead of just at the corners. I think the Av frame would be the weaker link but the more expensive piece. Good luck. Matt

 

[tomsr]

Well first of all, it wouldn't be worth it to me to go into all the work in building a hitch that may or not be safe and effective. The major hitch manufacturers have a lot of R&D invested in their products, so they don't end up in a law suit for product failure. I have been selling hitches for over 25 years, and yes at one time it did pay to build you own, and save a few bucks. Nowadays with everyone sue happy, our liability carrier will not back us on a homemade hitch if it fails. Also would your automobile insurance cover you if you built your own? Heaven forbid if you had a failure, or disconnect.
All things considered-it's just not worth it. But that's my opinion.

 

[Capecruis8der]

Ditto, what Tomsr Said
plus

A home made hitch will not meet a NHTSA standard
You make be creating problems for yourself
like

Being fined if pulled into a weigh station for the hitch not having a rated manufacturers capacity/tag

Building over kill, may temp you to tow more than the
AV can safely handle, endangering you and everyone around you

Not to mention the wasted time and effort to build and design one that looks good, when you can bolt one on in 15mins

Just my .02
RC >>>> NHTSA certified trailer manufacturer

 

[zuhl555]

Well, I found a decent price on a class 4 hitch with tongue adapter and got it. $130 for the hitch and 4" drop tongue insert. (whatever it is called). Don't know the name of the store but it was in Cedar Park, Texas. Just north of Austin. Had to mount it myself, but with 2 people, that was only a 20 min job. Now to get a wiring harness adapter.....