Square trailer

[pcrh]

I have a tandem axle flat deck trailer which I pull with a 81 GMC truck. Lately I feel a vibration in the truck from the trailer when on paved roads. I checked wheels for balance and bearings and no issues found. Now I am looking at the alignment of the axles. My question is how can I check if the axles are square to each other?

 

[jwal10]

Usually you will know because it is scrubbing the tires, odd wear pattern. Could be a bent axle. You can measure but hard to get near perfect. Check to make sure springs are on axle right, that you don't have a broken spring bolt. There are places that align trailer axles. Check at RV repair places. Also make sure hitch itself isn't worn on ball, causing "slop". Also make sure pickup is good and trailer isn't sending vibration back that you normally don't feel without trailer....James

 

[Roger in Iowa]

I have a tandem axle flat deck trailer which I pull with a 81 GMC truck. Lately I feel a vibration in the truck from the trailer when on paved roads. I checked wheels for balance and bearings and no issues found. Now I am looking at the alignment of the axles. My question is how can I check if the axles are square to each other?

Check all tires, truck and trailer, for lumps or squiggles from tire belts failing. Spin tires to inspect.

 

[pcrh]

Usually you will know because it is scrubbing the tires, odd wear pattern. Could be a bent axle. You can measure but hard to get near perfect. Check to make sure springs are on axle right, that you don't have a broken spring bolt. There are places that align trailer axles. Check at RV repair places. Also make sure hitch itself isn't worn on ball, causing "slop". Also make sure pickup is good and trailer isn't sending vibration back that you normally don't feel without trailer....James

Thanks for the suggestions. By measuring, I assume a common starting point for both axles like the front corners. Hitch is a pintle hitch and no ball. Will check this week.

 

[pcrh]

Check all tires, truck and trailer, for lumps or squiggles from tire belts failing. Spin tires to inspect.

Yes, tires are good and do not wobble or show signs of slop.

 

[Mule Meat]

How are you checking the tires balance?

The condition you describe sounds like one or more of the tires may have a broken belt.

 

[pcrh]

How are you checking the tires balance?

The condition you describe sounds like one or more of the tires may have a broken belt.

Balance tire by method I learned many years ago. Trial and adjust method until tire will not move from where I rotate it to. Then test on a different axle.

 

[J.Wondergem]

I have a tandem axle flat deck trailer which I pull with a 81 GMC truck. Lately I feel a vibration in the truck from the trailer when on paved roads. I checked wheels for balance and bearings and no issues found. Now I am looking at the alignment of the axles. My question is how can I check if the axles are square to each other?

The way that the truck and semi garage where I used to work has a small cable they hook to the fifth wheel pin and pull it tight a point equal on both ends of a axle.

 

[pcrh]

The way that the truck and semi garage where I used to work has a small cable they hook to the fifth wheel pin and pull it tight a point equal on both ends of a axle.

If I understand correctly this would tell me how square the axle is. Then I can adjust where needed. Did they set up 1 cable or 2 and then pull the axle square?

 

[J.Wondergem]

If I understand correctly this would tell me how square the axle is. Then I can adjust where needed. Did they set up 1 cable or 2 and then pull the axle square?

The semis have trailing arms on them. They adjust them with them.

 

[gable]

The way that the truck and semi garage where I used to work has a small cable they hook to the fifth wheel pin and pull it tight a point equal on both ends of a axle.

I'll fetch this square trailer this week and I'll see how bad the alignment. Left side tire has noticeable wear. The new BFG tires from 4Wheelonline for the truck showed up and I'll throw the used tires in the trailer. Gonna make the cable is well aligned.

 

[Tom in Mo.]

I've owned and pulled dozens of trailers and have never had one "out of square". the only one's ever seen out of square were the road trailers that were incorrectly slid into the wrong holes. Tandem axle trailers will wear out tires with a lot of sharp turns. One tire has to slip to turn on a sharp turn. I have an old heavy RV trailer that eats the right rear tire due to turns.
If your trailer is somehow out of square there will be a problem that needs repair that caused it.