Bumper-mounted trailer hitch bracket for Jeep Wrangler TJ

Well.... there is no Jeep in that one but it is a good illustration on the strength of bumper supports..

*******sigh******** I'm probably pissing into the wind on this one, but here goes anyway. Why not just do it, cover the situation where "Someone Else" might be tempted to overload it. This is called engineering. Plan for the worse.

The rev head culture amazes me too sometimes. Driving to the local shops in a 2 ton 4wd vehicle fitted out to blast through the Amazon Jungle defies logic. But as long as they dont do anything to kill me, they are welcome to it. So, by your logic, refusing to take even minimal precautions against misuse is OK because "other people" do even more stupid things. Do you write software this way?

Written by a true, tunnel vision, engineer. A pity that the rest of the world doesnt, or cant think like this.

Richard, you posted the design on this group. People responded. You negate any feedback you receive. They are not personal attacks - at least, not until you started responding in a silly manner.

One of the beginnings of maturity is recognising how little you know as an individual. Intelligence is then finding the information you need to overcome this. It is not just "Jeep trailer hitches" - its for the rest of your life, and your life to date, as well. Think about this - please - your life might start to get better and less confrontational.

Anderw VK3BFA.

I am an engineer.

I define engineering as the economical application of scientific knowledge to a physical application.

To "plan for the worse" is not engineering, if the worst is not worth planning for. It is spending too much on the biggest and baddest in the catalog, which is the anti-engineering mentality of "I built it as strong as possible, so I didn't have to think about it, nothing more could have been done". You don't build a wooden crate when a cardboard box will do, even though it won't stand up to a gorilla jumping on it.

Look, the item tows my boat, economically, and with some material analysis, albeit casual. It does not fit the worst case, nor is it intended to.

Ya gotta love Usenet. Posters simulating critical thought with platitudes, without knowing who they are talking to.

A (smaller) backing plate is only a glorified washer, good only against shearing through the attachment point. The rest of the bumper will have failed before that happens, so it adds nothing.

A larger backing plate would be tantamount to replacing the bumper with a stronger cross-member, and at that point you might as well put on a frame- mounted hitch instead of using the bumper.

Richard,

I like your definition of engineering. I guess I am a successful engineer, because I worked for exactly six years, three months after I got out of school, and I have been retired for eleven years since. I call that "the economical application of scientific knowledge to a physical application". Sure I could have worked for twice as long, had a couple heart attacks, and there would be enough money for my widow, kids and grandkids to never have to be afraid of poverty or hunger again. There is a parallel here, and someday I am going to figure out what it is. Until then, you keep doing what you are doing.

"Posters simulating critical thought with platitudes", I love this. Please feel free to post here again, the next time you engineer something. ;^)

Earle

Nah. Thats cost accounting. Design and manufacture something with the minimal cost and effort that will just do the job with no margin for error. When it fails, refer to "Definition of Engineering" and blame the customer for their lack of knowledge.

Sorry, wasnt aware I was talking to "an engineer". I apologise. Please forgive me for my ignorant comments.

Andrew VK3BFA.

If you get in an accident and someone gets hurt. only then, is when it really counts. You may get charged. I've seen hitches like yours and it was bent all to hell. Don't be stupid/cheap, pay the 150 fricken dollars for a proper hitch and be safe! This is NOT Microsoft where failures are sorta O.K. Dag nab it.

Debunked earlier in this thread.

Ok, now you are just being plain stupid sir.

You can be 'sure' if something happens and that home made hitch lets go and your trailer goes off and kills someone you will be charged.

Even in good ol Florida.

Your 'debunk' said nothing at all and I looked.

It was a BS smokescreen link that didn't cover the law about the structure of the attachment point or cover carrying a load too big for the hitch or vehicle.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Richard J Kinch proclaimed:

Rebunked. And even more happy instance, you can have your heinie sued off even if you weren't cited for excessive carelessness and wanton stupidity.

Still bunk.

Simply driving, nothing is going to "happen" with this hitch. In a collision, the violation and/or liability is with the driver at fault for the collision. Not with the hitch or its owner.

"Home made" has *nothing* to do with it.

Read the law. I cited it earlier. Florida makes absolutely no specific technical requirements for hitches, only that you have "sufficient strength to pull all weight towed" and that you have safety chains or other 49 CFR devices. You can tow with overcooked spaghetti if it has "sufficient strength".

People tow cars with rope and granny knots every day. Nothing illegal about it.

Thank God I live in Georgia, and it is illegal to tow with " ropes an granny knots ". Up here you get ticketed for not have a proper hitch. Just goes to show you that the Transplanted Yankees in Florida have had there brains fried too long out in all that sun!!!!

Richard being as how you have a Ph.D. I am going to assume you know the difference between ignorant and stupid. Well you can't say that you are ignorant, as too many people in here have tried to educate you on this matter, so what choice does that leave us with to describe you?

Tom

Rebunked agreed - There's nothing wrong with the design of the hitch plate you made itself, it looks plenty strong for the intended purpose, but the structural integrity of the bumper you /attached it to/ is a complete unknown.

Since the Feds stopped requiring bumpers to survive 2-1/2 and 5 MPH crash tests car and light truck bumpers are pretty much beauty items only, and some (especially the ones not designed as a trailer hitch) are virtually stamped from tissue paper and then chromed. You admitted it yourself that they're made to crumple - and you can't count on strength in towing from a known weak structure.

I would strongly suggest you go get a proper receiver hitch made that is tucked under the car, and remove the drawbar whenever you aren't using it - and if you do get hit in the rear, that tissue paper bumper will be the item hanging out there to get hit and try to absorb the forces. (Not.) But hey, it's your liability, not mine.

Nothing will likely happen to you legally now, the cops don't go around inspecting people's trailer hitches on a whim - until the hitch fails.

If and when it fails while on a public street or highway, and the trailer wanders off and kills someone or does some serious property damage, they are going to send out an officer (local or state, depending) to investigate and write the reports. And if the LEO sees a mangled mess on the back of the car that let go, they'll probably (as the old saw goes) "throw the book at you".

The Officers can easily reconstruct the accident scene - there are trained Major Accident Investigation Teams that do nothing but this, every day. They figure how fast everyone was going, do the math on the forces involved on the bumper in the accident, and prove that the weak link was the hitch that let go. They can prove that a properly designed hitch would have held under 2X to 4X (or more) of the forces involved in that incident - so whoever made that hitch is at fault.

In California, this would be one of the brickbats in said book:

Yes, you are in Florida - but most vehicle codes are similar.

-->--

They have educated me as to their casual opinions in conflict with concrete experience. Normal Usenet flux.

I'd be surprised if as you assert Georgia doesn't allow towing with rope. But I couldn't find the relevant statute, maybe you can:

The link below is to a page in the Florida Fish and Wildlife Conservation website. I will assume, with the known limitations therein, that it may be taken as an 'official" publication

Please see paragraphs 4 & 5 in section 1 Please see paragraph 5 in section 2 Please see illustration 2

You hitch design may be legal in Florida.... assuming that you can get the data from the DC engineering departments for "the weight rating of the bumper. "

However the factory manual shows the only approved (by DC) methods of attaching a towbar. In my XJ manual it is section 13 pages 7 & 8.

Does someone have a Wrangler manual that can check and post the appropriate pages in the Frames & Bumpers section?

I agree fully with Bruce. The 3/8" x 4" angle is plenty sturdy enough. That is not what everyone is complaining about. It is the 3/32" sheet you have attached it too that is not strong enough for a load.....Remember that a chain is only as strong as its weakest link and the weakest link hear is the 3/32" stock bumper!

But hey that is okay..... I just hope you sleep well after that bumper rips through and your trailer and angle hitch go veering off and hurt someone......

Get over yourself and stop being such a cheapskate! You seem to take pride in your cheapness and stupidity.......

Tom

Richard,

I will respect that you have made all the proper calculations on your boat and trailer weights and have for your education know the strength parameters and limitations of the Jeep Wrangler bumper attachment system.

That being said many of the people replying to you have years or decades of practical experience and many, myself included, have seen vehicles with their rear bumpers twisted or pulled off by what they were towing.

Imagine, if you will, a scene we all hope will never happen where you are in a courtroom with your spreadsheet defending your calculations and workmanship. The county prosecutor then calls a representative from Reese, Hidden Hitch, Valley, etc and asks them to display all the hitches they manufacture that fit the Wrangler.

The will come in on carts, of course, as they weigh in at 20+ pounds. The drawbars themselves are 3/4 inch steel the crossbars 1.25 or 2 inch steel pipe or tube, and the attachment plates while only 1/4 inch thick are 4-6 inches wide and attached by 1/2 inch grade 5 or 8 bolts. He will then pick up what is left of your bumper and twist it in his bare hands.

Are you wrong in an engineering point of view? No, but the jury is going to send you to prison anyway because they won't understand why the industry standard is 10x and yours wasn't.

Then you get to go home and explain, again, to your bride why her youngest child died. All the spreadsheets in the world won't convince her it was unforeseeable and unpreventable..

Please do not let your professi>

Jeep Wrangler Owners Manual.

I have one and it states:

"Trailer Towing Requirements: Class I Hitch (Light Duty) for towing trailers with a Gross Trailer Weight of up to and not exceeding 2,000 lbs. (907kg).

2.5L, engine with 5-speed Manual or any 4.0L engine / transmission combination. CAUTION! Do not use a bumper mounted clamp-on tow bar on your vehicle. The bumper face bar will be damaged."

Nuff said!

Tom

appropriate

Nobody will claim you need 1/2" steel for your hitch. However, engineering is usually about designing in safety margins to ensure people don't get hurt. Your tyres are engineered to take a much greater load than is applied by your Jeep, for example.

So the rest is philosophy ; given it won't fall off in an ideal situation - how much of a safety margin are you prepared to begrudgingly spend your cents on ? I guess the answer is "less than anyone else".

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ