What happens when a truck crashes pulling a 5th wheel trailer ?

Lets say it strikes something semi solid like an approach road or another vehicle... does the 5th wheel hitch mechanism fail and does the 5th wheel run into the back of the cab ?

My 5th wheel hitch is bolted to my truck frame via 4 5/8" grade 8 bolts as per the manufacturers instructions. (or are they 9/16"... I forget...) Seems kind of skimpy to stop that big trailer.

I've always wondered.

I'm towing with a short box and the pin is right over the rear axle, if that makes any difference.

Has anyone beefed up their hitch or hitch mounting ?

 

I heard on the radio on May 27th that a fifth wheel had turned over on the interstate in Cincinnati during morning rush hour . Answers to your questions would just be guesses because there's no predicting how components will hold up during a crash . There is a breakaway cable for the tailer brakes that should help prevent the trailer from hitting the cab if the brakes are well maintained . Safety chains are required on a gooseneck but not a fifth wheel and I have never heard of a fifth wheel breaking loose .

 

I guess it depends how close your 5th wheel is to the back window. Shouldn't go too much farther then the distance between the trailer drop and your rear bumper.

Hope you never find out

 

My newest trailer came with safety chains but its a 5th wheel coupler not a gooseneck. Its a flatdeck tandem dually.

I learned something here today.

I never could figure out the best way to hook up those chains. I also figured why would I need them as other applications do not use them.

I do hook up the breakaway though. Now I will just leave the chains hooked up on the trailer and tucked away.

Scotty

 

SECRET!!!!




Dont Crash!!

 

in a crash the hitch will probably fail it isn't designed to stop that much weight that fast, I saw a ford SD with a fairly good sized 5th wheel get into a wreck doing about 45 mph and the hitch failed and the truck jackknifed and still screwed up the back of the cab. The breakaway for the brakes won't help in this situation, it is supposed to stop the trailer on separation. it can't stop the trailer from trying to become one with the truck,

 

Those are 1/2" grade 5 bolts. They'll bend and stretch quite a bit before they break. They usually hang on pretty good bending the frame and trailer before they'll give up on each other. Here's a pic of a bad wreck with a 5th wheel... Huh? Can't attach a photo? It's a white F-350 with a large 5th wheel tangled up with another F-350 towing a big boat with both of them crashing into some rocks after crashing into each other.

 

grade 5? why not grade 8?

 

Grade 5 bolts will bend more than grade 8 when they fail, grade 8 tends to snap when over loaded due to the hardness of the metal.

 

I saw pictures of a truck and fiver that got hit by a semi trailer sliding on ice. The hitch bent and so did the pin box on the trailer. Neither one bent much, but they did bend enough to see it in the pics. They also did not separate upon impact either. I personally wouldn't worry about it, although I did put four more bolts (grade 5) to help hold the hitch to the box with backing plates.
Tom

 

Last summer a dura lilly ran into the back of a stoped semi in a construction zone. they couldn't get stopped in time after they realized traffic wasn't moving. I don't know how much the guy got it slowed before impact but the hitch broke & the 5vr hit the back of the cab. It was an extra cab made into a standard via the 5vr. The front end pused the radiator into the motor & buckeled the cowel & poped the windshield. The driver got cuts from the glass & his wife a broken leg & cuts. They were lucky they were able to get it slowed alittle before impact. Made that long bed quad cab look like a standard cab short bed with a cab over engine.

 

Last year on i-75 a crewcab Ford pulling a l-q horse trailer ploughed into the rear of a stopped semi which was part of the line that was stopped for a previous accident.Both occupants of the Ford were killed,the cab of the truck was rolledup and pushed into the box, other than a bent down pipe for the hitch there was no damage to the trailer,both horses in the trailer survived,unhurt!

 

To add,the installer of the hitch certainly did his job well !!!!!!!!

 

Hows a headache rack hold up?

 

I have had the unfortunate pleasure of seeing a number of 5th wheel crashes, all involving tourists with large holiday trailers. It would be nice if I still had the pictures of some of them to post here.

No fatalities so far, but I can assure you that the hitch never fails. 100% of the time, the truck frame folds in half as such. In a glancing corner shot, in one instance, the hitch did not fail, however, it tore the 5th wheel kingpin right off of the trailer, and threw the trailer into the ditch. Once again, the hitch wins.

A properly engineered hitch generally does not fail. I have seen homebuilt units crack and let go, but these were very poorly designed and executed. Apparently, the builders were, and should have been, as well.

In the archives of, how did that work, a 97 ford f350 extended cab 4x4 dually, pulling a 35' tridem holiday trailer, head on collision with a chevy 1/2 ton pulling a 25' holiday trailer. Both fifth wheel units, both moving slowly, less than 40 mph.

Ford frame literally folded up until the midpoint of the frame hit the road surface, and then maybe another inch or so, it was light on either end.
Chevy frame flexed and came back, as the hitch pin tore off the trailer, and took the back of the cab out. Thankfully the chev was also an extended cab, and no damage was done to drivers, or passengers in either unit.

Good hitches, lets make trucks and trailers to match

Happy Hauling