Sway Issues When Towing

[CraigS]

I did some more checking and the trailer alignment is good. I took a trip to the scales and here's what I found:
Truck with trailer kingpin in: 10,950 lbs.
Truck only: 8,500 lbs.
Trailer Axles (2) only: 11,850
I think this makes my pin weight 2,450. The total trailer weight (11,850 + 2,450) = 14,300
If i'm doing my calculations correctly, that means the pin weight is 17%. Does that sound right?
I've read some articles that say the pin weight should only be 10% to 15% and I've read others that say it should be closer to 20%.

[Country Campers]

Craig

Travel trailers usually like that 10-15% , I have learned on here that fifth wheels like to be around 20%. I am not sure that your 17% will make your issue but it could. Having to much weight on the axels or even behind them will be a contributing factor to your sway problem. Now I am not saying you need to load up the front to get more weight on the pin. But something you could look at is how your trailer is loaded. I know on our previous TT I could tell when I was not loaded right.

Brian

[DougW9876]

What do you have in the back of the trailer? If you have something heavy at the very rear of the trailer it can cause sway even if the balance is right, you don't want a heavy weight at the end you want it near the axels if possible.

[CraigS]

Craig

Travel trailers usually like that 10-15% , I have learned on here that fifth wheels like to be around 20%. I am not sure that your 17% will make your issue but it could. Having to much weight on the axels or even behind them will be a contributing factor to your sway problem. Now I am not saying you need to load up the front to get more weight on the pin. But something you could look at is how your trailer is loaded. I know on our previous TT I could tell when I was not loaded right.

Brian

Thanks Brian!

[CraigS]

What do you have in the back of the trailer? If you have something heavy at the very rear of the trailer it can cause sway even if the balance is right, you don't want a heavy weight at the end you want it near the axels if possible.

I don't have anything in the back. Just an empty "garage"

[jbarnes4868]

You should take the trailer to a truck alignment shop. Ours was way out and when corrected made s huge difference. Ours would isolate side to side during interstate driving.

[powerscol]

One other thing to check are you spring perch to see if the U-bolts are tight and the position of the axle perch correct. Some have found bolts loose. Are your trailer tires showing any odd wear? Do you have a friend that could follow you and video the sway? Another thing to check is jack up each trailer axle and check for end play/tire wobble. Also are your trailer tires balanced and do they run true? A tire shop can verify this.

Hope this helps

On edit - Does your truck have an anti sway bar on the rear axle? If not this could be the problem. The sway bar comes with the camper package but can be added through parts. Without that package I don't thing Fords puts them on.

A way to check if it the truck is load the bed of the truck with the pin weight (bricks, gravel, etc. and go for a drive. Another thought - do you have someone with a similar 5th wheel you could hook up and drive?

Just brain storming here.

[goducks14]

I did some more checking and the trailer alignment is good. I took a trip to the scales and here's what I found:
Truck with trailer kingpin in: 10,950 lbs.
Truck only: 8,500 lbs.
Trailer Axles (2) only: 11,850
I think this makes my pin weight 2,450. The total trailer weight (11,850 + 2,450) = 14,300
If i'm doing my calculations correctly, that means the pin weight is 17%. Does that sound right?
I've read some articles that say the pin weight should only be 10% to 15% and I've read others that say it should be closer to 20%.

Somethings off on the numbers somewhere. GD's brochure says 2475 lbs for dry pin. (I know brochure weights are fictitious.) You have 2450 lbs for pin. That seem virtually impossible with an empty garage. Just adding propane, batteries, items in the front cargo holds and in the bedroom would add several 100 lbs. You should be close to 2800-3000 lbs for pin.
The 320G starts at 20% for pin. Normal loading should keep it at 20% or greater so something weird is going on.

[whaines]

Check your truck on fifthwheelst.com Have the same truck and it would be overloaded with that trailer.

[BuddyLovesCamping]

I just purchased a Momentum 320G. It's the first 5th Wheel I've owned (i had a 30' trailer before). It has a sway to it when I go over 50 mph. I'm not sure what to do. I'm pulling it with a F350 short bed which has a GCWR of 26,500... so I'm under the weight limit. I have a Curt R20 5th Wheel Hitch.

The 5th Wheel tire pressure is good. Any suggestions on how to figured out why it sways so much?

The GCWR is not the only number you should be looking at. What is the Fifth Wheel Tow Capacity for your particular model of truck? What is the GVWR for your particular model of fifth wheel trailer? Are you towing with the fresh water (or other tanks) full or empty?

As mentioned by others, having too much weight behind the axles will definitely cause the tail to wag the dog. Having a lot of water in any (or all) of the tanks will slosh back and forth (and there may be hundreds of pounds of "sloshing" going on). Having a trailer weight that exceeds the tow rating of the truck is definitely a bad thing... and all too common. As a general rule of thumb, the tow capacity of the truck should be about 20% higher than the GVWR of the trailer.

I have a 2012 F350 crew cab, long bed, 4x4 dually with air bags towing a 2018 Solitude 344GK-R. It is rock solid stable, even when passing or being passed by 18-wheelers, and even with the fresh water tank 1/3 full (I generally don't tow with a full tank, except for short distances). The tow capacity of my truck (21,500) is 28% higher than the GVWR (16,800) of the trailer. It's a perfect combo and tows like a dream. (Oh, and I have the B&W Patriot 18K fifth wheel hitch.)

I suspect the fifth wheel tow capacity of your truck is lower than the GVWR of the trailer, or at least nowhere near the +20% safety value, so the tires, suspension, brakes, etc. may be inadequate or just barely adequate to handle the load you're hauling. Just a guess, since I don't know the specs of your system.