Tongue Flex and Tongue Box

[bdosborn]

Has anybody built a tongue box that rigidly attaches to the trailer body and the tongue? I was thinking about doing something like that but I'm worried that the tongue would flex and tear the box up. How much does an A frame tongue flex? I know it would depend on the strength of the tongue but should I look at some flexible mounting points at the tongue? The reason I ask is that I had an old jeep with a very flexible frame. The front grill was rigidly attached at the two frame rails and all the frame flexing tore the mounts apart. I reworked the grill mount to a single point on the cross tubes between the frame rails with a urethane body mount so it had some room to move and the problem was solved. Should I think of doing something like that for the tongue box?

Bruce

[cracker39]

Bruce, I've only towed my trailer about 15 miles to weigh it and return home. So, I don't have a lot of road time. My box on my TTT is attached rigidly to both tongue and front wall. However, my tongue is made from 1/4" thick 2" x 2" tubular steel and I don't expect it to flex...at least not enough to do any damage to my box that sits on the tongue and extends 18" from the wall. I've never read a post where anyone mentioned problems from flexing. I hadn't occurred to me that this would be a problem until you asked.

[bdosborn]

Dale,

It might not be a problem, I just thought I'd throw it out there and see if anyone else has had an issue. But, you might keep an eye on the bolts that attach the box to the tongue and se if they're loosening up or anything.
Bruce

[angib]

Bruce,

I'd say there are differences between the Jeep grille and the tongue box - for example, the Jeep is stressing a weak grille with a strong chassis, whereas a sturdily-built tongue box is probably just as strong as the A-frame.

But the big, big difference is in the number of wheels: the Jeep has 4, so it can put some big torsional loads into the chassis, which will flex - for example, when the vehicle is supported only on the front left and right rear wheels. However the teardrop has only 3 'wheels' (that is, two wheels and one coupler) so it doesn't have a way of applying torsion - it just moves to whatever angle the wheels are resting on. So there isn't a way in which the A-frame can be twisted.

The only thing to look out for would be whether bending of the A-frame would rotate a stiff tongue box upwards/backwards so that it pushed into the front of the roof - but I think it would just push the roof out of the way.

Andrew

[bdosborn]

Bruce,


But the big, big difference is in the number of wheels: the Jeep has 4, so it can put some big torsional loads into the chassis, which will flex - for example, when the vehicle is supported only on the front left and right rear wheels. However the teardrop has only 3 'wheels' (that is, two wheels and one coupler) so it doesn't have a way of applying torsion - it just moves to whatever angle the wheels are resting on. So there isn't a way in which the A-frame can be twisted.

The only thing to look out for would be whether bending of the A-frame would rotate a stiff tongue box upwards/backwards so that it pushed into the front of the roof - but I think it would just push the roof out of the way.

Andrew,

Point well taken. I hadn't considered the difference between 4 wheels and three. So now I guess the question is whether to build the front of the trailer really stiff to resist upward motion of the box or flexible so it can move to accomodate the flex. Or maybe just not worry about since no one has reported a problem.
Thanks,
Bruce

[Chuck Craven]

Bruce I don’t think that the tongue will flex more than a 1/8” to a ¼” in worst case.
I have seen some rubber donuts at ACE hardware. They were ½” thick by 1 ½” in diameter with a 3/8” hole in them. Can’t remember what they were for! But something like that could be use where the box mounts to the tongue to take up the possible flex.
Austin hardware may have something like that!
http://austinhardware.com/product.asp?d ... pf_id=1344

Chuck

[madjack]

Bruce, our front box is an integral part of the front bulkhead and basically, it "floats" on the tongue...the tongue is a 2x3/16th tube "A" frame...the box sits on the tongue but is not connected to it...about 1500mi so far with no visible problems surfacing...
madjack