trailer sway

What are things that would cause the trailer to sway while being towed? Feels like the tail wagging the dog.

Hi Don,

Here is a good primer:

Trailer Sway Causes

I haven't towed much but did experience the "tail wagging the dog" once when towing a U-Haul trailer. Not a fun feeling! That probably was a big factor in deciding to go with the Hi-Lo. Haven't had any issues with sway in my 2407T as of yet but I carry around the anti-sway device just in case.

Probably the first three things I would look at would be improper loading of the tow vehicle AND the trailer. Most weight in the trailer should be over the two axles if possible. Keep most of the weight in your pickup in front of the rear axle , again if possible. Also, item number two, would be checking to make sure your tire pressures were all on the money. Item number three is probably the most serious and that is the tongue weight of the trailer needs to be in line. A good starting place is 10% of the weight of the trailer, but that is not written in stone. You didn't tell us if you had a DWH by the way. And click on the link above to go over a really good check list on that sight.

What is the best way I can check my tongue weight? Can you use the truck scales on the interstate? Yes I do have a wdh hitch. My concern is I may not have it adjusted right

Hidonlo said:

What is the best way I can check my tongue weight? Can you use the truck scales on the interstate? Yes I do have a wdh hitch. My concern is I may not have it adjusted right

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Yes, you CAN determine the tongue weight at a CAT scale, but it takes two weighings. If you drop the trailer (tongue jack and axles on the rear scale) with your separated tow vehicle on the front two scales, you'll get the total weight of the trailer and the two axle loads of the separated tow vehicle.

Then, simply connect the trailer tongue to the towing ball of the tow vehicle. Leave the spring bars of the WDH disconnected, because they transfer some of the tongue weight back to the axles of the trailer. Weigh the combination again. The new weight of the trailer can now be subtracted from the disconnected trailer weight to find the tongue weight. The tongue weight should be between 10-15% of the total trailer weight to prevent trailer sway.

When you have the WDH set up correctly, it ideally adds the same additional load to the front and rear axles of the tow vehicle causing identical compression of the front and rear springs. This may be hard to achieve, but you do not want the front of the tow vehicle to be depressed MORE than the rear. You may have to settle for the rear springs carrying a bit more load than the front.

Additionally, when things are set up right, the trailer is nearly level when both the tow vehicle and trailer are on a level surface.

- Jack

notanlines said:

Probably the first three things I would look at would be improper loading of the tow vehicle AND the trailer. Most weight in the trailer should be over the two axles if possible. Keep most of the weight in your pickup in front of the rear axle , again if possible. Also, item number two, would be checking to make sure your tire pressures were all on the money. Item number three is probably the most serious and that is the tongue weight of the trailer needs to be in line. A good starting place is 10% of the weight of the trailer, but that is not written in stone. You didn't tell us if you had a DWH by the way. And click on the link above to go over a really good check list on that sight.

Click to expand...

Don't see your link, Jim.

Don, in addition to the things Jim mentions, I've found speed is a big factor in causing sway. When I was pulling that U-Haul, I had to really slow down to make it stop.

Will there be a fee or need to set a time to use the scales? Yes when it hit bad I was on a down hill and maybe going to fast to past a semi. Lession learned. The bottom edge of the trailer does seem higher in the front

Hidonlo said:

Will there be a fee or need to set a time to use the scales? Yes when it hit bad I was on a down hill and maybe going to fast to past a semi. Lession learned. The bottom edge of the trailer does seem higher in the front

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CAT scales do costs. Explain what you are doing and they might give you a deal.

I was going to write a detailed procedure but I found this one online:
Woodalls Open Roads Forum: Travel Trailers: How do I weigh my TT?. Look at the post written by Ron.

If the scale has a single pad you can still do all the above. The difference is that you will be taking total weights and doing some subtracting: 1- TV front axle, 2- TV front and rear axle, 3- TV front and rear axle plus trailer weight.

Look up a commercial scale in your area and find out when they are the least busy. I've found the operators to be very helpful and accommodating if they don't have a line up of 18 wheelers behind you.

Hidonlo said:

Will there be a fee or need to set a time to use the scales? Yes when it hit bad I was on a down hill and maybe going to fast to past a semi. Lession learned. The bottom edge of the trailer does seem higher in the front

Click to expand...

The high front end on the trailer COULD indicate not enough tongue weight. The air turbulence off a semi is known to cause trailer sway on a trailer that is not properly set up. I've never had sway with my HiLo and my Equil-I-Zer hitch that has built in sway control.

A LONG time ago, when I was in the Air Force, I had to tow something from one end of the runway to the other, and I was hurrying. There was no sway control on the hitch and I got horrible sway. So, I'd say speed can definitely contribute.

The fee for using a CAT scale should be nominal. I THINK it cost me $7.00 for each weighing here in Arizona. They were very accommodating. I was allowed to just stay on the scale while I disconnected, weighed, and then reconnected and weighed again. Before I got on the scale, I told the nice lady what I needed to do.

- Jack

Greg, I actually was referring to the link in your post. And, no, everyone is correct in their thinking, I didn't make it very clear. But, nonetheless, the link is still there. And now to reference another post further down, it is kind of interesting and considerably more accurate to use the method of the 2x6 and the bathroom scales. Truck scales are a little closer to being accurate on 50k lb loads.