Tongue and axle questions

[madprinter]

I've gotten my frame body welded up. Its 2x2 14 ga. tubing 12' long 6'4" wide. I have a piece of 3" x1/4" round steel pipe I want to use for my tongue. It will go two feet under the frame to the 2nd crossmember and have 4' sticking out in the front. Then I'll run two pieces of 2x2 14ga. angled into it near the coupler. Does anyone see a problem doing the tongue in this manner?? Is it stong enough?
My 2nd question is about axle placement. I don't plan to have a galley.
The bed will be crossways in the back and most of the weight will be in the front. I'm guestimating a totol weight of 1500 lbs. But honestly don't have a clue . How far from the rear would you place the axle?? Thanks for all the help.

[G-force]

That tonge should be plenty strong, but really heavy, that 3" .250 wall tube is around 7 1/2 pounds a foot. 2x3x 1/8 rectangular tube is half the weight and with 2x2 A frame supports, well exceed the requirements for a 48" tounge with a 1500# trailer. The axle will need to be somewhere in the neighborhood of 60" forward from the rear end of the trailer, according to the caculator on this site.

[angib]

This is a good example of the problem of single tongues - the tongue may be stronger than the frame it is attached to.

That 3"x1/4" tube, on its own, is strong enough to carry a load on the coupler of 900lb which the Aussie rules say is OK for a 1800lb trailer.

However..... with 4' of the tongue exposed and 2' under the trailer, a 900lb load on the coupler puts a 1800lb load on the second cross-member and it's nowhere near strong enough to carry that - in fact, I reckon it will start to collapse at only 38% of that load.

This is exactly the problem that some forum members have reported with the single tongue Tractor Supply trailer, so it's not some theory-only problem.

For your design with two 2x2x14g angled braces, I reckon the combined tongue can support a coupler load of 850lb (instead of 1400lb if the second cross-member were much stronger) - the Aussie rules reckon that's OK for a 1700lb trailer, but for a teardrop I reckon you can double that number.

So your combined tongue should be strong enough, but it's the two angle braces that are doing most of the work, not that heavy 3" tube.

I think you may need to look at your 1500lb weight estimate again - that's quite a low figure for a 12' x 6'4" trailer body. Are you planning to build lightweight? (That 3" tube suggests the answer is 'No'.)

Andrew

[Alphacarina]

A 2 inch pipe should be more than strong enough for his application, shouldn't it Andrew?

It would be less than 1/2 the weight as well

Don

[madprinter]

Thanks for the input.
Andrew, To tell you the truth, I really don't know what my final weight will be. I keep changing my mind on the construction. I guess I've always been like that. I just wake in the morning and look at it from the perspective of the day. I built a two story house the same way. Its not
the best aproach I'm sure. I apreciate you and the others for your guidance.
William

[madprinter]

I ended up using a piece of 2 1/2 " X1/4" pipe for the tongue with 2 2x2's coming into it from under the trailer to the second crossmember. I reinforced the second crossmember with a piece of 1 1/2" x 2" angle iron welded the full legnth and welded into the tongue gusset and to the two 2x2 angles going to the tongue. I also added 3x3 1/2"x1/4" gusset plates to all the crossmembers. Tacked my spring mounts on and discovered my dexter alxe has a problem with end play at one of the hubs, I'll be exchanging it this next friday for anoughter one. I'll post some pics when I get time.
William

[G-force]

End play? Are you sure the cotter nut is adjusted properly? If your not familiar with how the bearings in a trailer spindle work, now would be a good time. Short of something being machined wrong (possable, but not likeley), if the spindle is wobbling, and the bearings and races are new (is it a new axle?), it probaly just needs adjustment. Perhaps the race was not fully seated when manufactured. Pop the end cap off, remove the cotter pin and tighten the axle nut firmly with a socket, about 20 foot pound. Turn it by hand a couple of revolutions, then back it off untill finger loose. Then finger tighten it, then back it off to the next slot that the cotter pin will fit in. Might want to also repack the bearings with grease while your in there.

[madprinter]

I thought it just needed adjusting too, took off the cap pulled the pin. It had a full 1'' of side play. The alxe is new. Something went wrong at the factory. I'm just going to swap it for anoughter new one. It may be a simple fix, But i drive past the dealer everyday so, its easy to exchange it.
Everybody has a blunder every now and then, guess I just got theres.