trailer 101?

Owning about 5 right now, I'd have to say that trailers are pretty simple. The basic wiring diagram for lights is on the back of most lighting replacement parts that you buy at Wal-Mart. Bearing buddies are needed for boat trailers to keep the bearing cavity pressurized to exclude water intrusion, otherwise are not necessary on trailers that don't go into water. Jack up a side and give the wheel a spin, if it sounds smooth, it's probably OK. You may want to repack the wheel bearings since it's new to you, but I doubt if you ever will need to again. I've owned my 16 footer since '91 and have never repacked the bearings. Don't beat on the hitch mechanism with a hammer. Beyound that, there's not much except replacement of rotten wood (which never seems to be done the first time with treated lumber).

Reply to
Gary Brady
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Don, do you know what may happen if the trailer IS attached with safety chains, but becomes unhitched. Have you seen that happen?

i who always uses safety cha> >

Reply to
Ignoramus22711

Those are a couple of great links.

This one adds 5-6-7 wire connectors, wiring diagrams to the mix if needed.

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Reply to
RLM

I don't think that you are supposed to weld anything to your truck frame...

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Reply to
Ignoramus22711

Grant Erwin wrote: but I'd really like to know quite a bit more

I have never seen any book that covers the basics. And I am sure that I won't cover everything, but others can add the things I miss.

  1. The tow vehicle must be heavier than the loaded trailer and have a hitch rated for the loaded trailer.
  2. The tires must be rated for the load.

  1. You must have trailer brakes above some loaded weight. Your trooper friend can let you know the law.

  2. The center of gravity must be in front of the wheels. That is as others have said the tongue weight needs to be about 10% of the weight. But think of it as the center of gravity must be ahead of the drag.

  1. The center of pressure must be behind the center of gravity. I have never seen this stated anywhere, but it is something I believe. If you have questions on this google on model rocket design. This is pretty much the same as 4. but saying that the center of gravity must be ahead of the aerodynamic drag. Again not to the extreme or cross winds will be a problem. My guess is the center of pressure ought to be over the wheels.

Dan

Reply to
dcaster

I've seen the remains. When things are set up properly with chains that are long enough to allow sharp turns but short enough to keep the trailer under control AND the load is set with the usual 10% tongue weight, the trailer tongue just drops down and bangs around. Usually grinds some metal off the chains (requiring replacement), grinds metal off the coupler or the small foot just behind the coupler, and/or bangs the hitch into the bumper or rear gas tank. You hit a bump, the hitch comes off, you hear a LOT of noise from the rear, you see the dust and sparks in the mirror, you slow down quickly, assess the damage. Beats killing someone in the oncoming lane.

If things are NOT set up properly, things get nasty. If the chains are too long, the trailer tongue thrashes all over the place, may inflict serious damage to the tailgate/trunk. If the load is unbalanced, too much load in the rear, the tongue will rise up, tongue is guranteed to clobber the rear of the tow vehicle as well as a good chance of fishtailing from side to side. UGLY. Worst case is for the trailer to come unhooked and do a head on collision with the opposing lane. REALLY UGLY. I have a co worker who was killed a few years back, we had a camper trailer do in a family of 4 a few miles from me this summer. It does happen.

I have a specific caution for RCM types: A standard single axle trailer loaded with something heavy like 2000 pounds of sheetrock can tow quite nicely. Just load it with 10% of the weight on the tongue, low wind resistance, life is fine. Now load the same trailer with the same weight Bridgeport mill with it's high center of gravity. On level ground, you can load it with 10% on the tongue. When you go up a steep hill, the CG of the mill shifts back, all the weight comes off the tongue, you have no control. Plus if your trailer coupler is going to pick a time to let go, this is it. Wind resistance is just going to add to the effect.

No one else has mentioned it but remember your brakes. Most states don't require brakes on trailers under 3000 pounds (some states have lower limits). Put a 3000 pound trailer on the back of a 4000 pound tow vehicle and your stopping distance almost doubles. Hit the brakes and it feels like a giant hand is pushing you through the stop sign.

And > Don, do you know what may happen if the trailer IS attached with

Reply to
RoyJ

Thanks Roy. I have a 3,500 lbs boat on a trailer. So far we did not have accidents, but the old trailer rusted to the point of nearly falling apart. When I saw cracks in it, I was #%#%$ing shocked.

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Reply to
Ignoramus22711

Be sure to look at the springs. I had an axle come out from under an old boat trailer (with a heavy boat and motor) I had just bought in the dark. Spring broke coming around an intersection at about 5 MPH. I had just pulled it 50 miles at freeway speeds!

Since yours was in an accident, alignment might be in order. Alignment is simple. With the trailer on level pavement, measure from the center of the hitch to a point on the axle near the wheel, repeat for the other side. Measurements should be near identical. 1/8" out is OK. If there is a second axle, it should be parallel to the front axle. Align the front axle first.

Ron Thompson On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA

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Reply to
Ron Thompson

Yep. And Im a hell of a lot better welder these days. While not cosmetic....that little episode caused me no end of personal embaressment and has challenged me to not only learn to weld better, but engineer better as well. I welded up a cart for a buddies Bridgeport the other day, out of 5" channel. He wanted to be able to move it around the shop at will. It, when there is a BP on it..is .625 off the floor. I gave it to him Wed..and he called me up Friday to compliment me on the welding. Seems the dumb bastard...sigh...couldnt find his slings...so used a couple motorcycle tie downs to lift the BP up and set it on the cart.

The straps busted 6" above the cart.

He said there are marks on the floor where the cart bowed and hit the floor...but nothing bent..is still square and all 4 wheels still touch equally. It bowed..then came back into square.

Fortunately..the tire (and mount)..cringe..came off out in the desert..and has likely become the happy home for a family of Bishops Chipmunks (just doing my part for nature of course..cringe..)

My shop is your shop.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

Reply to
Gunner

All EXCELLENT advice!

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

Reply to
Gunner

OK, 10% tongue weight seems to be the norm. How do you know when you are there, in the real world? Without unhooking the tongue and weighing it? Even then, you would need the weight of the loaded trailer to do the math. I always measure the distance form the tongue to the ground empty, then again when loaded. If the tongue goes down, I can assume there is weight on the tongue. But, I don't know exactly how much. How do you guys know when its right?

Reply to
Chief McGee

A properly designed empty trailer will have about 10% of its weight on the tongue. When loading, just distribute the load so there's about

10% more weight in front of the axle than behind it.

The vehicle-squat test isn't a bad measure. Have a 150 lb person stand on the hitch (with trailer empty) and measure how much the hitch goes down. Then two guys -- or the 300 lb gorilla you have helping you if you're lucky. You now have two datapoints from which you can estimate tongue weight.

Reply to
Don Foreman

I have never had this happen. I'm careful about using good hitches, securing them closed with a padlock, and always using the right size ball.

Note that safety chains should be crossed. In MN it's state law. The point is moot if both chains are fixed to the same point on the tongue, as is the case on my (factory-made) boat trailer.

I also mouse the hooks on the chains. A piece of heavy rubber with two holes in it that are slightly smaller than the hook diameter provides a quick and convenient way to do that.

Reply to
Don Foreman

Actually, heavier tongue weight is better so try the "if you can lift it, it's not enough rule" For the utility trailer class: 1000 pound trailer is 100 pound lift, not too bad, 2000 pound load is 200, you need to be in good shape, 3000 pound trailer, 300 pound tongue weight, only gorillas need apply.

I know what my trailer weighs, I usually do a quick calc > OK, 10% tongue weight seems to be the norm. How do you know when you are

Reply to
RoyJ

On Sun, 22 Oct 2006 19:25:08 GMT, with neither quill nor qualm, "Chief McGee" quickly quoth:

When you can just barely lift it off the ball, it's about right.

- The only reason I would take up exercising is ||

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Reply to
Larry Jaques

The only trailer tail that I have is for a motor cycle trailer. Bike trailers have the ball joints on swivels so that you can lean the bike over without leaning the trailer over. I was going three-quarters round a roundabout (traffic circle or rotary) with the empty 150lb trailer behind the 350lb Moto Guzzi V50 MkII. I took a line around the inside lane of the roundabout and forgot that the trailer would take a smaller radius. The trailer his the inside kerb and neatly flipped over. It slid quite well on it's fibreglass lid. Luckily it was fairly controllable and there were no other drivers close to me, but the front end of the bike had a mind of its own for a few seconds.

I used to take that same trailer into work on occasion, when we didn't have a car, to do the weekly super market shopping. The works roads have evil little speed humps. I've been told that it is quite terrifying to follow a trailer behind a motorbike when the trailer suddenly jumps two feet into the air :-)

Mark Rand RTFM

Reply to
Mark Rand

I don't own a trailer, but have one trailer story. I was driving along at highway speed when I noticed the left wheel wobbling on the trailer behind this large utility truck. (They seemed to be mechanical contractors of some kind.) I pulled up parallel and waved for them to pull over. They (a team of five including the foreman) did, and were pretty glad they stopped. That wheel was wobbling side to side by about six inches, and was going to come off real soon now. So, they crept off to their destination, where they could repair it.

Joe Gwinn

Reply to
Joseph Gwinn

I can vouch for the scariness factor in that situation . Was following a buddy out of his driveway last weekend when his left trailer wheel caught an edge . And that side of the (loaded !) trailer went about 2 feet in the air . He didn't even react ... but I noticed he kept the speed down until we got the cooler on the front loaded with a case of beer and a coupla bags of ice . Then we gave it hell ! When I build my trailer , it's gonna be one of the inline type . Saw one last spring an occasional poster here (and in other groups I read) built , and like it a lot . He used a modified universal joint for a hitch ...

Reply to
Snag

I'll second that opinion. I have those two books - fortunately they were given to me and I didn't fork out the bucks myself - and there is some useful info in them, but not much of what you'd expect, need or wanted.

The 2nd vol has tables (copied from elsewhere) that come in handy just because I know where to find it.

If the 3rd vol ever is published I'd be tempted to buy it to see if the author can ever commit himself to a 'here, do it this way because....' statement. Nah!, buy a tool instead.

Reply to
John Miller

By the way, regarding tongue weights. Weight up to 300 lbs can be measured with a bathroom scale (usually they go up to 330). Obviously, you need to place a board between the trailer jack's roller and the scale. An exercise of how to easily extend it to 660 lbs, is left to the reader. Myself, I just use the gorilla test method.

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Reply to
Ignoramus22711

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