Minor sway issue

RobWNY wrote:
I received an email response from Sean at ProPride. Here it is

"Removing too much weigh off the rear axle of the tow vehicle by raising the weight distribution jacks too much can certainly throw some movement into the hitch and then the trailer. The hitch will only move from the tow vehicle side so if the rear end is light it could have been drifting a little at higher speeds."

Rob, in a previous post, you stated:

"---When I crank up the weight distribution as far as I can, I can't get the truck back to where it was before hooking up. I can get the front within 1/2" of where it was originally and the rear of the truck to 3/4" of where it was originally but that's all.---"

On your recent trip, do you think you were able to crank up the weight distribution enough to restore the front axle load to its unhitched value?
Even if you were able to achieve 100% front axle load restoration, your 1100# tongue weight still would be causing a load of around 800# to be added to the rear axle of your 2500HD.

Have you ever noted any tendency for the rear of the truck to "drift" when not towing?
If it doesn't "drift" when not towing, I'm wondering what might be causing it to do so when you are towing with an additional load of 800# or more on the rear axle.

Removing too much weight off the rear axle would be accompanied by adding to much weight to the front axle -- both of which could cause an "oversteer" condition.
During those periods when the rear of the trailer was swaying back and forth about 3 inches, did you notice any increased sensitivity to steering inputs?

If you are able to reproduce the TV and TT loading with the WDH adjusted as it was when you were experiencing the swaying, it would be very informative to measure the hitched and unhitched axle loads under those conditions.

Ron

Hi Ron,

No, even cranking the weight distribution as much as I did does not make any difference in where the rear and front of the truck ends up. It's the same with any tension I use but I don't have the slight sway issue when the weight distribution isn't cranked up as much as I had it for my trip home. The truck doesn't drift at all when not towing either. Steering has never been an issue so I'm sure the weight on the front axle is sufficient sice that height changes so little regardless. On my next trip out, I'm going to just use the weight distribution at it's minimum. The Chevy specs say I don't need it at all when towing less than 13,000 lbs. but because it's part of the hitch system, I have to either remove it completely which I don't want to do or at least get them tight enough not to dangle in the wind. We'll see what happens and if there's improvement or it's worse, I'll report my findings here.

Rob,

Since changing the height of the WD jacks did not cause any changes in the deflections of the TV's front and rear (up 1/2" in the front and down 3/4" in the rear), it is reasonable to conclude that raising the weight distribution jacks did not cause too much weight to be removed from the rear axle.

This leaves two other possibilities to consider:
1) the sway you experienced was caused by raising the jacks -- but, via some other mechanism, or
2) the sway you experienced had nothing to do with the raising of the jacks.

In consideration of 1), it would be good to hitch the trailer and raise the jacks is several steps while checking the condition of the hitch and receiver at each jack height.
A close up photo of receiver, hitch, and bars at each step might be informative.

In consideration of 2), have you followed the recommendation of BarneyS to check the frame bracket assembly which controls lateral movement of the rear end of the yoke?
Also, have you checked the connections at the front of the yoke, and have you checked the ball and coupler for any looseness?

Good luck with your search for the cause of this sway.
Please keep us posted on what you find.

Ron

PP3 or HA is not a cure all for sway problems. It does a fantastic job of masking towing issues such as improper trailer weight distribution and poor hitch set up.

The OP needs to go through a complete hitch set up with the truck and trailer loaded for a trip.

Ken

Rob, I just purchased a ProPride for our 2016 Jayco 28BHBE, being towed by our 2006 GMC Sierra 1500HD. I towed our trailer home about 200 miles yesterday for the first time, and I experienced the same thing you mentioned; a little "sway" at times from the trailer within the 65-70mph range. I even felt it at times when a car would pass me. It never was close to what I had been experiencing with our prior, inexpensive, hitch setup, but definitely a surprise given the claims of the hitch and other users. It was never uncomfortable to me, but was surprising none the less. And while I definitely agree with a few of the posters here in this thread, that there is no substituted for correct loading and WD, it still surprised me because I have weighed everything and found things to be right where they needed to be.

Sean had told me before I left for our trip to bring the WD jacks up a bit further if we felt any porpoising, which we did for the first 10-15 miles. But now I'm wondering if I just cranked them up a bit too far. We started around 3 inches up, but then went to 4, so it wasn't a major increase. But even that one inch seemed to make a difference.

Anyway, just wanted to let you know I experienced the same thing you did. We aren't going camping again till the end of Sept, but I'll make a few adjustments and post back my experience. I'd be interested any adjustments you make and your experiences as well.

miyzfrider, Overall I'm sure you will be very happy with the ProPride. I know I am. I will be putting less tension on the jacks as Sean at ProPride has suggested on our next trip in two weeks. I will also report my findings. I'm betting this was the cause and all will be fine. Congrats on the new camper and ProPride!

You mention towing with a 2015 GM 2500. one thing I discovered with our new 2015 GMC 2500, is it came with 20" wheels. On our first trip out, I had the tires at 60psi front and rear towing the same trailer I pulled with our 2004 2500 exact same configuration, CC/SB/4x4. while we didn't have sway, I noticed the truck "wiggled" more than the 04 did when going around corners or changing lanes. like it had soft sidewall tires. DW commented. Next trip I put the back at 80psi, big improvement, but still not as stable as the 04. This last trip I went to 80psi all the way around, and it made a dramatic improvement. Now it behaves like the 04. However the 04 was not near as sensitive to tire pressure.

Both trucks were set up with the reese dual cam, I had readjusted it for the 2015 since the 2015 is 2" higher than the 04. had to drop the ball, and readjust the bars to get the front to settle correctly, did all that before the first trip.

Now I wonder if getting the 18" tires would have been a better choice, or if it is just the stock 20" LRE tires have a softer sidewall than the tires I ran on the 04 (Michelins). I was expecting the 20" 55 series tires to actually have less flex and a stiffer sidewall than the 16" on the 04.