Truck disconnected from RV.

[Bryantclan]

So after ~500k miles over 3 RV's and 5 different tow vehicles we had our first (hopefully last) really bad event towing.

First the setup: We have a Newmar AllStar 3950 towing a GMC 2500 HD. We use the 10k rated roadmaster tow bar and the 10k rated Blue Ox safety cables along with the air force one braking system. The truck was 7162 pounds when I put it on a cat scale while connected to RV ~1800 miles before.

While merging on to i70 after a quick rest, the hitch pin for the tow bar gave. Which was followed by the two 10k pound rated tow cables breaking and the truck taking a separate trip from the RV. Thankfully it went down the 30-foot embankment into a plowed field instead of going into oncoming traffic. The crazy part is after some digging and removing the managed tow bar I was able to drive it out and other than some damage to the air dam it seems to be no worse for it and there is no damage to the RV.

What I have yet to figure out, why did the safety cables both fail? Had the truck decided to go left instead of right it would have gone down a steep grade on to a very busy highway which would have likely been disastrous.

[znt1186]

May be it is just me, but it looks like those cables are quite corroded. Corrosion on cables happens more on the inside than the outside, so you can't always see the corrosion on the inner strands of the cable. Why did the hitch pin fail?

[Bryantclan]

That was my first thought as well, you can't see the cables normally as they are wrapped in plastic. I washed down the ends because I thought the same thing and they came back shiny with no rust. They also failed evenly which suggested they were just stressed beyond there load limit. What concerns me is either of them should have held the truck by a 30% margin.

[MSHappyCampers]

WOW! That's scary! I guess you just have to be thankful that nobody was hurt!

[firedoc]

What are your thoughts on failure of the hitch pin. Did pin fail or more likely the retaining clip allowing the pin to fall out.? Any evidence?

[TonyMac]

Did the breakaway brake activate before the toad got to the length of the safety cables? I see this setup all the time, and is seems illogical. The breakaway lanyard needs to be longer than the safety cables/chains, so the breakaway does not activate while the toad is safely held by the cables. The breakaway should activate once he cables give out and the toad is indeed away onits own.

[powerboatr]

glad you and no one else were hurt or worse.


but not to pick...but how old was your hitch pin? and man you got lots of rust going on,

how old were the cables?


i agree the cables look awfully rusted at the failure point ( by your picture) and YES the corrosion you see on the outside only lends a small eye on the internal failures.


maybe the cable got a huge stress applied that also exceeded their margin of safety.

i say this because..once the hitch pin failed, did the auxiliary braking device
then apply full brakes and thus this applied the large load on the cables and they failed due to being weak from corrosion, along with the first jerk of the hitch failing, followed by the other Jerk of the towed brakes trying to stop the truck?


BUT wow you are lucky, or rather the people on the road with you are lucky no one got creamed by the wayward towed.

[masdixdragon]

Wow, seriously lucky with this disaster..glad things didnt turn out worse

Wrapping the cables like that encourages corrosion especially if subject to any salt environment. Moisture will wick along the cables quite easily with exposed ends like that. In many suspension bridges they grease them for just that reason. Also kind of surprised that cable arrangement doesnt have a radius shield at the connection point but that wasnt the failure point FWIW. Looks like they are burst rated not working load rated IMHO...looking at the end result little wonder they let go from corrosion at even half that. Also each one was probably stressed individually during sway so its not 10K + 10K...only 10K at a time under ideal conditions (i.e new cables)

[Beach Aire]

Well, I had somewhat of a similar experience about 3 hours out of Tok, Alaska this past summer.
On mine, the whole base plate assembly broke loose from the vehicle, and the only thing that was holding the Mini Cooper to the RV by the time I stopped was about 1" of weld. If that last piece of weld would have broken, the car would have ended up somewhere in the Alaska forest! The Blue Ox base plate is connected to the front bumper assembly on the Mini Cooper, and of course, the front bumper assembly is designed to break away in the event of a frontal impact. After 50,000 miles of pulling on the welds connecting the bumper assembly to the front radiator core support, they finally decided to give up!
I ended up doing some modifications in Alaska, and now the base plate is connected to the radiator core support and the front engine/transmission mounts. Much more sturdy than the original design.

[Bigd9]

I'm so glad nobody was hurt and you guys are all OK. That had to be scary!

[TonyMac]

The cable failure could have also been caused by the tow bar pole-vaulting itself into the ground. Were the cables wrapped around the tow bar? It looks like the base plate attach points are bent inward towards center, which would contraindicate the pole-vault theory and indicate the premature application of the breakaway brakes. How far did the truck travel after it broke loose? It seems far from the road in those pictures. Did the breakaway brakes even apply?

[Domo]

We're all glad there was no one hurt and that the truck did not become a missle crossing the median or spinning in your lane.

You never mentioned a breakaway device.

Aren't they required by law for anything over 3,000 lbs including trailers and towed vehicles that are not under their own power which defines them as a trailer in the Fed law. Just curious did it engage.

Thanks for posting - it's a reminder for everyone to check their equipment, just as a trucker does every time they take off. Plus, look close in case some punks thought it would be funny to disconnect your tow bar or pull your breakaway pin while you run into a gas station.

[raineman]

To me, that setup has a considerable amount of rust and corrosion to the point I would not have used it. Glad no one was hurt.

[momdoc]

Wow glad no one was hurt.
I agree with the many comments that the cables were bad (rusted) causing the failure.