Towbar/tab failure

[cwdavis]

We had a moment of excitement recently, pulling out of an RV park onto US 1 in Lexington, SC. Looked in the side-view mirror, only to see our toad peeking out, looking like it wanted to pass us!

Turns out, our 12 year old tow package had a failure: one of the tabs protruding from the front of the car that interlocks with an arm of the towbar broke off, leaving the car attached by only one arm of the tow bar. This allowed the car to swing more widely, side-to-side, which is exactly what I saw looking at it in the rear view camera.

We were fortunate in many ways, one of which is that we were able to stop without any damage to either vehicle, by allowing the coach to coast, allowing the car to 'snuggle' up against the rear of the coach, and to then come to a stop. We unhitched the car, and drove it the rest of the way home.


Click For Full-Size Image.


Click For Full-Size Image.


Click For Full-Size Image.

The tow unit was a Blue Ox, Aventa II, towbar that mated with a baseplate for a 2001 Acura MDX. Here are some photos of the failed tab -- note especially the hairline crack on the intact tab. It's in exactly the same place as the break point of the broken on.

We reported this incidence to Blue Ox, who has responded as well as one might hope. They are shipping a new set of tabs, and paying to have us ship the old one back to them for inspection.

[hanko]

Mile High wrote:
Mine are definitely not aluminum, heavy as heck.

sorry, they are steel

[Mile_High]

Mine are definitely not aluminum, heavy as heck.

[hanko]

gat75 wrote:
My first thought is that this would probably never had happened if this part had been machined out of solid bar stock.

Off course, it requires much longer time (hence more money) to fabricate parts from solid stock.

What do you think they are machined from, they aren't cast, or permanent tool mold, they are in fact machined from solid Aluminum Bar stock. Not sure what your looking at

[Hank_MI]

I have 2 sets of tabs, neither has the extra holes. They also look to be machined from solid stock. Our tow bar is maybe 7 years old, the knuckle on the end of the tow bar arm is attached off center, towards center of toad, not in the middle as in the older design shown in the pics. I believe this reduces sideways stress on the tabs as well. Those with the older design knuckles may want to talk to BlueOx about the design change. Maybe worth replacing those as well.

[Gjac]

gat75 wrote:
My first thought is that this would probably never had happened if this part had been machined out of solid bar stock.

Off course, it requires much longer time (hence more money) to fabricate parts from solid stock.

I can't imagine that Blue Ox would ever make this piece with out machining it from solid bar stock.

[Gjac]

I also have a 12 year old set up from Demco. It has one tang on the tow bar eng that slips into two tangs on the base plate. These tangs have opened up several times and I finally added 1/2 in backer plates on either side to keep the base plate tang from opening up. It looks like the three tang design would prevent that. My conclusion from observing this is any slop in those tangs make the side to side motion worst. Steel in pure tension is very strong its the bending modes that weaken due to the slop in that joint. My only suggestion is to check for worn or egg shaped pins, holes or excessive slop between tangs. What was the tow bar rating and what did your tow car weigh?

[irishtom29]

Tinstar wrote:
I have tried to get in touch with Blue Ox but they don't respond to email. How do you contact them?

Their website has their address and phone number. Write them a letter or give them a phone call.

[Tinstar]

I have tried to get in touch with Blue Ox but they don't respond to email. How do you contact them?

[Mile_High]

If it was a matter of older design, I would suggest anyone that has tabs with the 2nd hole replace them. Blue Ox may even offer to do it for you if there has been issues in the past that caused the design change.

[tropical36]

Pretty scary and I to, like many, have or will be checking out their tow bars and base plate, no matter what the brand.
With my setup in particular, utilizing a READYBRAKE/ELITE and coupled with a DEMCO baseplate, I just can't see anything such as this, ever happening, so it might be time to take a good look at the design in general and no matter how many new ones, BLUE OX is willing to send you for replacements.

[Mr_Mark1]

I just checked my 'tabs' (didn't know they were called tabs)... we have the single hole and no stress cracks.

Safe travels,
MM.

[cwdavis]

Several people asked about the 2nd, lower hole in our tabs. I have no idea of their purpose, and as as several people pointed out newer tabs from Blue Ox lack them.

No, we did not drill them in; they were in the original tabs we installed a dozen years ago.

Yes, they were definitely the site of the cracks one can see in the intact tab, so they do seem to have created a weak point in the tabs.

[cwdavis]

Bumpyroad wrote:
did your toad braking system help out?
bumpy

The car was still attached to 1 arm of the tow bar, Bumpy,
so the aux. braking system was not activated.

[Shot-N-Az]

OK, I wonder how many of us read this, got up, and went out to check our tabs. I know I did.

Thanks for the post and I'm glad it wasn't worse for you.