maiden voyage a little jittery

[les45]

Took my new weekender on its maiden voyage today in preparation for our first real camping trip next week. Just drove about ten miles down the road and got it up to highway speed. At speed (55) it is fairly smooth, but at lower speeds it has that little bit of jittery or jerky feeling coming back up through the TV. It's kind of like it's reflecting every little bump in the road. It is a 5X8 NT trailer with 5.30X12 tires at 50 psi. The wheels are not moved back (still in stock position). The ball sits about two inches above level so I plan to get a new drop hitch to make it sit level. I estimate that the rig weighs about 1,100 lbs empty and it has about 100 lbs of tongue weight. I plan to load all the camping gear in the front of the cabin to increase the tongue weight.
Any thoughts on why it's got that jittery/jerky feeling? It's kind of like when you are hauling an empty trailer. I keep reading on most of the others' posts how they can't even tell that their tear is back there when they are towing.

[48Rob]

Hard to say, but I'd first suspect the low tongue weight due to the trailer not being level, and 50 psi in the tires...probably much like a hard rubber ball bouncing down the road?
What is the weight rating for your axle/ trailer?

Rob

[mikeschn]

It's kinda hard to tell from your pictures where the wheel is... Do you have a shot looking at the side view?

What's the dimension from the back of the body to the center of the wheel?

Mike...

[les45]

Hard to say, but I'd first suspect the low tongue weight due to the trailer not being level, and 50 psi in the tires...probably much like a hard rubber ball bouncing down the road?
What is the weight rating for your axle/ trailer?

Rob

The GVW is 1,980 lbs and it is a standard 1" axle like on most of the HF and NT trailers. Should I be running lower pressure? I've always used about 55 psi on my similar HF utility trailers and that has worked pretty well with them. The tires are rated 1,000 lbs at 80 psi.

[les45]

It's kinda hard to tell from your pictures where the wheel is... Do you have a shot looking at the side view?

What's the dimension from the back of the body to the center of the wheel?

Mike...

The distance from the rear of the frame to the center of the wheel is 42" and I have 12" of body overhanging the frame front and rear. I decided not to move the axle back with the thought in mind that I would increase my tongue weight by loading my camping gear forward in the cabin. I was running empty today so the tongue weight wasn't what it will be. I think Rob is right about the combination of low tongue weight and high tire pressure causing the problem. I'm hoping it settles down with a lowered receiver and more tongue weight. I don't want to mess with the tire pressures before I sort out these other variables.

[CliffinGA]

Les take it out with some weight in it and also check and tighten your lug nuts, most people forget to check them after they take it out for a first spin.

Cliff

[les45]

Les take it out with some weight in it and also check and tighten your lug nuts, most people forget to check them after they take it out for a first spin.

Cliff

Hey Cliff. Thanks for the reminder. My brother almost found out about the Chinese lug nuts the hard way on his HF trailer. He had some to come completely off one time although he caught it before the wheel came off. I always check mine with a torque wrench before every run. The NT book says 90 ft-lbs and that is what it gets. I think after I load it up properly and get the new lowered receiver that it will settle down.

[48Rob]

The GVW is 1,980 lbs and it is a standard 1" axle like on most of the HF and NT trailers. Should I be running lower pressure? I've always used about 55 psi on my similar HF utility trailers and that has worked pretty well with them. The tires are rated 1,000 lbs at 80 psi.

Hi,

If the trailer is rated at 2000 pounds, the axle/springs are likely rated the same or a bit higher.
If your trailer weighs 1100 pounds you're not at the optimum loaded weight, which in my opinion is around 2/3 or so of the total.
If your springs are rated at 2000# then you are about 233# shy, if the axle is rated at 2200# 433# shy.
With so much difference, the springs (torsion or leaf) can't be expected to provide optimum cushioning.
And running the tires with 55psi doesn't give them much room to offer a cushioning effect either.
By adjusting the springs to suit your load (the manufacturers pick a middle ground that will work for the highest number of consumers, then add a fair amount for liability) you can have a trailer that rides and handles very well.
Adjusting the tire pressure after that is icing on the cake.

Once you get the trailer level with your tow vehicle, you should notice a difference, as well as when you rearrange weight, or add weight to get the tongue weight closer to 150# or so.
If you still have problems after all these adjustments, the axle location may be a bigger issue than you thought.
If so, try adding another 100-150 pounds of tongue weight (for a total of 200-250#) if it settles out then, depending on how it handles, moving the axle may need to be considered.
You can use math to determine the difference between the tires rating, and the actual load.
1000# capacity @ 80PSI calls for .08psi per pound.
At 550# per tire, you should have around 44PSI.
To fine tune it/them further you can use a piece of chalk to mark a line across each tire tread, and driving a mile or so, you can quickly tell if there is too much, or too little air in the tires.

Rob

[les45]

Thanks, Rob, I hadn't thought of the tire pressure being proportional to the load like that. I'll try the chalk method to check it out. I was concerned that reducing the tire pressure too much would cause sidewall flexing and possible failure. I would be interested in what others are running for tire pressures in those 12" DIY trailer tires.

[CliffinGA]

Les may drop in and say howdy this weekend, we 're camping south of you over in Oconee Sate park and we're going to Devils Fork the next weekend!

Cliff

[les45]

Les may drop in and say howdy this weekend, we 're camping south of you over in Oconee Sate park and we're going to Devils Fork the next weekend!

Cliff

Please do! I would love to show you my new ride. We'll be getting there sometime Friday afternoon and will be there through Sunday about mid-morning. Obviously, you won't have any trouble finding us. We will be with a small group and may be in and out with some hiking and stuff. I'll PM you with my cell #.

[CliffinGA]

Got it bud and we'll definately meet up then!

Cliff