Help me understand sway - 6K trailer, 2001 Expedition

[hertfordnc]

Former trailer was a 65 Boles Aero 27-footer. This was a very well made trailer, on a par with Airstream (don't tell them that) It towed beautifully with just a simple WD hitch. No sway control.

We recently moved up to a 74 Boles Aero 32, (we like 'em old)

It's four feet and maybe 1400 lb bigger, at around 5800. Doesn't feel much heavier but at anything over 50 MPH it gets squirly, pushes the truck around and starts a slow sway oscillation that gains until i slow down.

The suspension is the same on the two rigs, double drop axle with a shared hinge in the middle. The 74 has shocks which i assume are completely worn out.

Tires are old but OK and filled hard.

So, where do i go first to look for trouble? I could add sway control but I'd rather address other issues first as I think this trailer should tow better than it does.

Thanks

[handye9]

There are several things that affect sway issues. Your problem could be one, or a combination of two or more. Right now, there are too many unkowns.

Most common cause is tongue weight. You don't know what yours is.

Other items:

Weight distribution. If you have too much weight taken off your drive axle, subtle hand movement on the steering wheel, can cause sway. You don't know what your weights are. Thus, you don't know if your distribution is enough.

Hitch height. Affects tongue weight and WDH.

Tires. Both TT and tow vehicle, need proper tires with proper air pressure, and, they should be balanced.

Missmatched tire tread can affect sway. You already know you have one odd tire on the trailer.

Bent trailer axle.

Weak suspension on tow vehicle. Maybe, you have some body roll.

A short wheel base (TV), towing a long trailer, will be more affected by wind. ie: it won't take as much wind to push you around, as it did with the shorter trailer.

Try the following measurements, maybe, it will point you in a specific direction. Take truck and trailer to level ground, then:

1. Unhitch and level the trailer, as if you're camping. Measure the height of the top side of coupler. Check all tire pressures.

2. On the truck, pick a spot (near center,but, out of your way for hitching up) on front and rear bumpers, and stick a piece of masking tape. Measure unhitched height of the tape and write it on the tape.

3. Measure hitch ball height. It should be within one inch of coupler height. Adjust as needed.

4. Hitch up, without weight distribution, and measure truck bumpers (same spot as before) and write that on the tape.

5. Hook up weight distribution and measure truck bumpers (same spot as before) and write that on the tape.

6. Push on side of trailer and watch how it affects the truck.

7. Push on the side of truck and see how much (if any) body roll or sway you cause.

Hitched up, with weight distribution, your front bumper measurement should not be more than 1/2 inch higher than the unhitched measurement. Your rear bumper measurement, should be slightly lower than unhitched measurement.

If rear bumper is higher than unhitched measurement, you have too much weight distribution. If front bumper measurement is too high, you don't have enough.

Now you have an idea of how the trailer is affecting the truck, and, you have an idea of what your suspension is doing. With and without weight distribution.

This would also be a good time to hit CAT scales and get real numbers on truck weight, truck and trailer without weight distrubution, and truck and trailer with weight distribution.

The masking tape and CAT scales will cost less than 20.00 and probably a day of your time. But, you will know wether or not, the truck is up to the task, and, wether or not, the weight distribution is doing what it is supposed to be doing.

Replacing a tow vehicle, tires, a bent axle, or, upgrading truck suspension, could get spendy.

[hertfordnc]

LT tires on the truck. New on the back decent on the front. Trailer tires are three ST 225/75 and one 7 X 15 - all have some cracking. All will be replaced in the coming year but are suitable for local trips.

The truck is 4X4, 5.4, factory tow, which includes big trans cooler, and i believe a larger radiator.

When towing the 4500 lb trailer the trans temp stayed around 160F I think. I don't recall the temp but it was no different when not towing so i figured i had a lot margin to go to the bigger trailer. Trans temp is currently inop but I'll fix it before serious travel happens.

[BenK]

hertfordnc wrote:
Thanks all.

I am not resistant to tongue weight as a possible solution but I'd have to just put lead on the tongue because the weight distribution is pretty well set by the layout.

Do you think the Expy is too small for the job? Towing capacity is around 8200 lb.

That is only true for a 'curb' Expedition and yours' is NOT if you
have any options other than the towing option. Any options you do
have (AC, upgrade interior/exterior, etc) takes away from the 8,200
MTWR pound for pound

Also, unless you weigh 150lbs, that takes pound for pound away from
that 8,200 MTWR.

Ditto anything else loaded into/onto the TV (people, pets, luggage,
etc)

Why best to to out and weigh it fully loaded, axle by axle

I am not resistant to any suggestion. I'm trying to get some theory to work from.

The trailer tires are decent but not great.

Big flag to me...Expedition, so a half ton SUV and OEM is 'P' class
tires (passenger class).

The tow is level by eye.

Measure it and/or post a pic

As for setting up the WD, it's a simple reese system, at least 15 years old, maybe 20. On the old trailer I put it on and it worked great so i never really educated myself in the finer points of adjustments.

Why asked if the head is tilted, etc...there are several adjustments
that worked for the old trailer, but is totally out of wack with the
new trailer

thanks

Oh, does your Expedition have the air suspension? Know some had it, but
don't remember which years available as an option

[hertfordnc]

Thanks all.

I am not resistant to tongue weight as a possible solution but I'd have to just put lead on the tongue because the weight distribution is pretty well set by the layout.

Do you think the Expy is too small for the job? Towing capacity is around 8200 lb.

I am not resistant to any suggestion. I'm trying to get some theory to work from.

The trailer tires are decent but not great.

The tow is level by eye.

As for setting up the WD, it's a simple reese system, at least 15 years old, maybe 20. On the old trailer I put it on and it worked great so i never really educated myself in the finer points of adjustments.

thanks

[K_Charles]

You said you put on the WD hitch but you never said you set it up for the new trailer. Proper tongue weight and setting up the hitch set up are the two things that will fix your problem. Like said above, either that or don't tow the trailer.

[mkirsch]

hertfordnc wrote:
Just for fun, let's take tongue weight off the list.

This trailer has the bath and waste tanks aft of the axles. The fresh tank over the axles.

Other than the kitchen cabinets there is no storage forward of the axles.

So if you load it up for a long trip it will be heavy in the back and there is nothing you can do about it.

Right now the tanks probably have about 25 gallons in them. Most of the storage is empty.

Then I guess you're screwed. Park the trailer and never tow it again, or sell it...

Seriously, you can NOT "take tongue weight off the table." It's the single most important factor in known sway situations. 99.9% of the time the sway due to inadequate tongue weight!

[BenK]

Not enough info

How many miles on your Expedition?

What condition is it in? Mainly the IRS pivot joints

Is the TV lifted?

Over sized tires? What is the PSI on the TV's four tires and what
is the sidewall max PSI?

Any other mod's to your TV?

The trailer weight you report is on the high side of any half ton, IMHO

Is the trailer tongue level at it's highest pointing? Better to be
slightly down.

What WD Hitch system are you using, what is the bar rating, head
tilt, etc

You also are guessing on way too many points that need actual numbers

Suggest you make a trip to local weigh station, garden supply, etc
that has a scale. Weigh the whole setup axle by axle and if they will
allow, with and without the WD Hitch tensioned and not.

Much more info needed before any of on the Internet can diag your issue(s)

[hertfordnc]

Just for fun, let's take tongue weight off the list.

This trailer has the bath and waste tanks aft of the axles. The fresh tank over the axles.

Other than the kitchen cabinets there is no storage forward of the axles.

So if you load it up for a long trip it will be heavy in the back and there is nothing you can do about it.

Right now the tanks probably have about 25 gallons in them. Most of the storage is empty.

[Airstreamer67]

I would suspect tongue weight. It should be between 10% and 15% of the trailer's total weight. You won't know this unless you weight it.

Also, check wheel bearings, tires, suspension, frame to make sure all the mechanicals are OK.

Find the source of the problem before thinking of a $2500 superhitch that will mask the sway but not cure the cause.

[Peg_Leg]

You can prove the tongue weight theory easily. Make a base line run and note the speed at which the sway begins. If you have a fresh water or holding tank in front of the axles, fill it up. If you can't do the water put something heavy inside and as far forward as you can. Case's of soda, can goods what ever but it needs to be a couple of hundred pounds.

You could also unload something from the back but this would take twice as much weight for the same result. Now go for a spin and if tongue weight is your problem the speed at which sway begins will be higher.

[rexlion]

Adequate tongue weight is the first factor to look at. But when you start towing such a long trailer (especially relative to the Expy's wheelbase), I'm not surprised to hear that the tail is trying to wag the dog. I would not personally tow that unless I had a top notch sway control hitch. Why gamble? The body shop can't fix the dents in a human being. Get a ProPride or a Hensley.

[hmknightnc]

hertfordnc wrote:
Yes, I towed it once without the WD and it was horrible then i put it on and it was only slightly better.

Did you adjust it for the heavier trailer? The bars will need be tighter due to the increased tongue wieght of the new trailer

[bigcitypopo]

I'd say you need a little more tongue weight...

I have had a few rigs, truck and trailer combos.I am most fond of my current truck/trailer, and my Hensley. I have had the equalizer, the eaz lift and they worked good with the right tongue weight.

Two crucial things. The right tongue weight, adjustment of the hitch height, and use of sway control. None of which you can't nail down till you get it weighed.

I did all of that, and then invested in a Hensley. But that being said. Get it weighed. Go on a day when its slow so you can "play" at the scales. Get it right, tow it around and adjust, re-weigh, the
N tow it around.. Adjust. It took my three trips, about 75 miles in all, 25 each trip to find it..

In those 25, I have a 5% grade... A stretch that causes a porpoising effect, and flat land with a mild turn about 6 miles long.

Have some fun with it. One you get it right, it's great, towing setup right should be an easy drive.

[hertfordnc]

Yes, I towed it once without the WD and it was horrible then i put it on and it was only slightly better.