Recovery with ball hitch?

[TheNerd]

I'll agree with Matthew Curie...those cheap hitch pins can withstand a lot of shear stress...but bending stress is another story! At least the hitch pin method is loads better than using the hitch ball! NEVER use the ball...it will become a cannonball when it fails!

A little napkin calcs over here are telling me that loading the pin directly with your recovery strap will basically result in the same stresses as doing it through a hitch insert.

Pulling on the hitch Pin (Simple supports, disctibuted loads):
Max Shear ~ 1/2 Pulling Force
Max Moment (Bending) ~ 1/4 Pulling Force

Pulling on the Hitch insert (Simple supports, twin loads / 4-pt. bending):
Max Shear ~ 1/2 Pulling Force
Man Moment (Bending ) ~ 1/4 Pulling Force (I rounded 7/32 up to 1/4... so this is technically slightly less bending on the pin)

...so save your $$$ on a shackle hitch and pull right on the hitch pin. Plus, if something were to fail, you have a lot less mass flying around...

 

[Markos]

huh???

only thing welded is the hitch itself... not sure what the "hitch drop" is.... maybe where the safety chains are attached if actually using it to tow. I wouldn't recomend attaching and recovery equipment to these.

tow ball (w/o ball) with shackle (where the ball used to be) connected with a nylon tow strap.

has always been solid for me...

I was referring to the weld that joins the hitch tube to the ball mount. As seen below:

My only concern would be the unlikely event that something like this would happen. The only sceneario that I could think of would be a shoddy ball mount along with repeated hard pulls.:

If you are going to skip out, go the hitch pin route. One less point of failure.

 

[srimes]

A little napkin calcs over here are telling me that loading the pin directly with your recovery strap will basically result in the same stresses as doing it through a hitch insert.

Pulling on the hitch Pin (Simple supports, disctibuted loads):
Max Shear ~ 1/2 Pulling Force
Max Moment (Bending) ~ 1/4 Pulling Force

Pulling on the Hitch insert (Simple supports, twin loads / 4-pt. bending):
Max Shear ~ 1/2 Pulling Force
Man Moment (Bending ) ~ 1/4 Pulling Force (I rounded 7/32 up to 1/4... so this is technically slightly less bending on the pin)

...so save your $$$ on a shackle hitch and pull right on the hitch pin. Plus, if something were to fail, you have a lot less mass flying around...

That's what I wanted to hear. Sounds pretty good, the only question is the validity of the distributed load model for the tow strap. Best case it's evenly distributed, but worst case it's more of a point load. What's the max moment with a point load in the center of the pin? It's been a few years since I've taken "mechanics of materials" ...

 

[srimes]

That's what I wanted to hear. Sounds pretty good, the only question is the validity of the distributed load model for the tow strap. Best case it's evenly distributed, but worst case it's more of a point load. What's the max moment with a point load in the center of the pin? It's been a few years since I've taken "mechanics of materials" ...

Ok, responding to my own post...

I spent 10 min. refreshing my memory on the internet and sketched it out.

I came up with a max bending moment for a center point load of 1/4 LW.

I don't know the gap between receiver and hitch, but I assumed W/10 as an example. I sketched it out and came up with a max bending moment for this of 1/20 LW.

That's a big difference. And it makes sense that it would be. The question is how well does the tow strap distribute the load? It will depend some on the strap may be less than you think, maybe only distributing along the center inch, or even 1/2 inch in a worse-case scenario.

And then there's the testemony of those who haven't had any problems with it, and if it did fail it would probably do so realitively safely.

 

[Semper Fi]

I have a question for all of you. I will agree that if a ball would break it could become a "cannon ball", but how many of you have seen this happen? As far as that goes, how many of you have had this happen? I have pulled a 28 foot trailer with a ball and have had no problems with failure. I know my Jeep weights less then my trailer. Just asking!

 

[JohnR]

I've seen it happen before. Getting a ~5000lb trailer rolling and up to speed doesn't require that much pulling force. Haven't you seen the strong men competitions when a single man pulls a bus that weighs ~30klb? It's the yanking that breaks them.

 

[8Mud]

I have a question for all of you. I will agree that if a ball would break it could become a "cannon ball", but how many of you have seen this happen? As far as that goes, how many of you have had this happen? I have pulled a 28 foot trailer with a ball and have had no problems with failure. I know my Jeep weights less then my trailer. Just asking!

It's likely if the vehicle is stuck, the force required to get it moving may be many times the weight of the vehicle.
I've seen the bolts for the hitch shear at the frame. I've seen the frame tear.
On a flat tow, my setup is twice the towed weight of the vehicle (minimum). A slack and snatch type of situation can double the force really quick.
Force is actually more relevant than weight.
Dodge engineers, used to be really good at setting up tow hooks and hitches (in the seventies). They used a combination of slotted and round bolt holes and different grades of bolts. The grade five may shear, then the the grade 8's would slip in the slot and catch. You'd hear and feel a big bang and know to go look at the shear bolts. Kind of a simple fuse, to help you avoid something worse.
Just because the hitch seems solid doesn't mean the whole unit and mounting is.
Plan for the worst, hope for the best. It's always a good idea to engineer, your tow points to be a factor of the towed weight, not a fraction.
Think big. You may get away with it, until you don't, then Murphy strikes.

 

[Blaine B.]

The guy talking about using a D ring instead of a ball - No... As far as I read it, I believe he meant to remove the Ball (where it would normally bolt down) and just insert a D ring into that same hole. That insert (which inserts into your hitch) will bend regardless. Find something else or use the strap around the pin method.

 

[PornstaR]

As stated above the cheapest route would be prolly the most unsafest. Why not just go buy a peice of 2x2 tube drill some holes in it. Get a pin and pin it in the hole and do a little mods to it so it can hold a shackle?? Also I dont thing a ball is ever going to "sheer" off the hitch but hey anythings possable. But again this is america and if it does snap off just sue someone.................. thats the american way. Be an idiot and sue someone else.:doh:

 

[Blaine B.]

huh???

only thing welded is the hitch itself... not sure what the "hitch drop" is.... maybe where the safety chains are attached if actually using it to tow. I wouldn't recomend attaching and recovery equipment to these.

tow ball (w/o ball) with shackle (where the ball used to be) connected with a nylon tow strap.

has always been solid for me...

Yes though, the "drop" can bend.....Just like if you wrapped the strap around the ball. The ball can snap and project, or the entire drop can bend. Only difference is the shackel won't snap and project, but I do still believe the "drop" can bend if enough force is applied.

I'd say it's on the end of the "safest ways to recover"....

 

[95meangreen]

come on buy are tow hook reciever or D ring shackle..... you spend all this money on upgrades without even thinking about it. This is one of the most useful tools spend the 30 to do it right. because i would be pissed as hell when the ball or the drop came propelling in my direction. Do everyone a favor and do the safe thing: buy something that is engineered for recovery not for towing your boat

 

[Matthew Currie]

The good ones won't break, but....

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[ddeadserious]

Seriously guys, recovery is the single most important thing while off roading. You don't need a lift, you don't need huge tires, but you do need to have proper and safe ways to be pulled out if you get yourself in a predicament. If you put unsafe recovery points on your Jeep, aside from risking the safety of yourself, you moreso risk the safety of whoever is kind enough to pull you out. $30 is alot less than the hundreds of other things that many decide is more important like swaybar disconnects or a nice stereo. /rant

 

[Blaine B.]

The good ones won't break, but....

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Prime example

 

[Ralph]

Seriously guys, recovery is the single most important thing while off roading. You don't need a lift, you don't need huge tires, but you do need to have proper and safe ways to be pulled out if you get yourself in a predicament. If you put unsafe recovery points on your Jeep, aside from risking the safety of yourself, you moreso risk the safety of whoever is kind enough to pull you out. $30 is alot less than the hundreds of other things that many decide is more important like swaybar disconnects or a nice stereo. /rant

Well said, sir.

Money well spent.

 

[Blaine B.]

Only reason that'd be unsafe was if you had a rust-weakened hitch

 

[TheNerd]

I came up with a max bending moment for a center point load of 1/4 LW.

Using the same numbers from before, I get a max Moment of about 1/2 the Pulling force...or roughly TWICE the bending moment of a distributed load...so your concerns on the validity of a distributed approach are quite valid...