Sway Question

[BaysideBruce]

I am not sure what happened but suddenly I have a sway problem.  Last year I drove over 2600 miles with my trailer and did not have any sway problems.  This year I traded my Silverado Pickup in for a Tahoe SUV.  I had to lower the hitch by 3 inches so the trailer would ride level.  I also installed a Prodigy brake controller.  (It showed a "C" when connected to the trailer and up to about 33 when stopping quickly.  I am assuming that is what it should be reading.)  Those are the only differences from last year.  If I had to, last year I could drive 70 MPH and not have a sway problem.  This weekend we went on our first camping trip of the season.  At 60 MPH I was white knuckling it on the interstate.  I drove 55 MPH and was on edge all day long.  I now know how the dog feels when "the tail wags the dog."  I pulled over twice thinking that maybe I had a low tire.  I checked the pressure in both tires and they were the same, 60 psi.  I checked my sway bar and tighten it some but nothing helped.  I packed the trailer the same way that I had last year so I don't think the weight distrubtion in the trailer changed any.  What else can I check?  I am at a lost on what to do.  The sway bar did not seem to be helping much or if it was, the sway problem is even larger.   The bearings have a little over 2500 miles on them since they were repacked last year.  The wheelbase of the Silverado and Tahoe are not that much different.  Any suggestions??!!
Thanks

[brainpause]

This will be interesting to watch. I hope you find the problem.

I don't have a Coleman trailer, but something in the back of my head tells me the tires need to be 80 psi??? Check the sidewall or your owners manual. I know you'd love for it to be that simple!

I hope you find the problem. If it isn't weight distribution, $100 bucks will get you some cheap insurance in the form of a sway control.

Larry

[mike4947]

If the trailer tires were at the max pressure listed on the sidewalls, and you had the sway controller on and functioning. Then it's either the receiver or the TV suspension.

First thing I'd look at would be increasing the rear TV tire pressure.
Seems there's several GM OEM "P" grade tires that don't exactly had the stiffest sidewalls. Jack the pressure near the maximum will help hold them in line. If worse comes to worse replace them with the equivalent "LT" grade tire.
 
As for the receiver check to make sure the bolts are all tight. They can loosen or simply sheaar off, and it only takes one to set up some weird oscillations.

[kathybrj]

Just a question that came to mind but how much of a wheel base measurement difference from the old vehicle to the new one? It may not seem like much but it could make a difference?

When we went from a longer wheelbase tv to a shorter one, and not by much but we had to adjust our reese hitch to keep the sway down.

[tlhdoc]

I lost about 10 inches going from my Windstar to the Explorer.  I never had sway on the Windstar, with the Explorer I had to purchase a sway bar.  I think your tires on the trailer have 65 psi max.  Pump them up to the max.  When you get sway do you brake the TV?  If you do, don't.  Just brake the trailer with the Prodigy and accelerate the TV if you can.  The other thing I would look at is your tongue weight.  Make sure it is 10 to 15% of the trailer weight.  Good luck and let us know how you make out.

[BaysideBruce]

The differences between the Silverado and Tahoe are not that much.  The wheelbase of the Silverado was 119 inches, the Tahoe 116 inches.  The width is identical, 79 inches.  

Yes the max air pressure of the trailer tires is 65 psi. Like is said I had 60 -61 psi pressure in them.  Will try it at 65 next time out.

Because I could not use my orginal ball hitch, I got a new one that lowered the hiegth so that the trailer was sitting level when it is connected to the Tahoe.  This hitch did not have a metal bar welded on to it for the sway bar, so I bought the "add-on" sway bar arm that is bolted onto the hitch by being placed under the ball and tightened.  I am not sure if this add-on arm is the same length as the welded on arm that was on the old hitch.  If it's not it is only an inch or two smaller.  But that does mean that the sway bar is connected to the hitch closer to the ball.  Also the ball is about 2 inches closer to the TV than it was with the other setup.  Still plenty of room though to hook-up and for turning.

I bought new Kelly tires for the Tahoe.  They are P265/70R16.  I have no idea how the stiffness of the sidewalls compare to other tires.

Kathybrj - how did you adjust the reese hitch?

[wynot]

I tow a Utah with a Tahoe.  Run 65 in the camper tires (cold pressure).  Run at least 40 psi in the Tahoe rear tires.  I assume you have at least 10% tongue weight, and either an empty or full freshwater tank.  Make sure your friction sway slider bar is clean and free of all brake dust.  This needs to be done at least annually.  Make sure that the adjustment lever is oiled.  Tighten it to 2 finger tight.  If you haven't cleaned your sway bar, you're really going to be suprised - the brake dust glazes your friction bar.

[AustinBoston]

1) Does the Tahoe ride more like a car than the Silverado did?  Soft suspensions are a major contributor to the likelihood of sway.

2) Is there water in your fresh water tank?  The only way to tow a Bayside is with an empty tank.

Either way, a sway bar will settle things down instantly and magically.

3) Does the Tahoe sag when you hook up?  If yes (by more than 1 inch), then  it's time for a weight distributing hitch.

Austin

[whitestar505]

BaysideBruce,
 
I had the same problem last wekend with no change of any sort on TV. What I did was tighten the sway as tight as I could, Within reason, and backed it off a half a turn. My tires state that the MAX PSI is only 65. They were at Max.
 
Good Luck
 
PS: Your new tv may be wind dragging differently then you old tv.

[kathybrj]

Kathybrj - how did you adjust the reese hitch?

On the Reese mini 350 (WDH), there is a plate that has a hole in it, but the hole is not directly centered. I believe this is the plate that does the adjustment for the hitch.

I don't know about other Reese hitches.

[wynot]

3) Does the Tahoe sag when you hook up? If yes (by more than 1 inch), then it's time for a weight distributing hitch.
 
Austin

Big problem with this is that most Tahoes have load leveling suspensions.  Within 1/2 a mile, I couldn't tell you if it had sagged initially or not.

[wynot]

BaysideBruce,
 
I had the same problem last wekend with no change of any sort on TV. What I did was tighten the sway as tight as I could, Within reason, and backed it off a half a turn. My tires state that the MAX PSI is only 65. They were at Max.
 

If you're using the same tightness you always have, you need to clean your sway bar, you've glazed over.

[BaysideBruce]

Thanks to everyone for all the recommendations.  I have NOT cleaned my sway bar very well lately, so that will be one of the things I will do first.  Any recommendations on what to use or not to use on it.  I have a can of spray brake cleaner, I am assuming that would be okay to use.  

I have given some thought to the fact the the aerodynamics is different for the Tahoe then the Silverado.  I'm just wondering if that is making the difference.  Anyone else with a Tahoe who found the effect of swaying increased?

I do not carry any water in the fresh water tank.  (One of the things I checked on the emergency road side stop just to make sure.)  On the way back I did leave my hot water heater full since that was up in the front truck and I wanted to get as much weight up there as possible.  Not sure if that made any difference.

Thanks again to everyone who's make suggestions.  I appreciate them all.

[wynot]

Thanks to everyone for all the recommendations. I have NOT cleaned my sway bar very well lately, so that will be one of the things I will do first. Any recommendations on what to use or not to use on it. I have a can of spray brake cleaner, I am assuming that would be okay to use.
 
I have given some thought to the fact the the aerodynamics is different for the Tahoe then the Silverado. I'm just wondering if that is making the difference. Anyone else with a Tahoe who found the effect of swaying increased?
 

Pull the bar out of the friction pads, then do it.  Wire brush or benchgrinder wire wheel.  This breaks through the glaze.  
 
And as odd as it sounds, make sure that your adjustment screw threads are oiled and clean.  They can be rust colored, but not rusty.  What happens is that you progressively get less and less tension on the sway bar with more 'stuff' in the threads.  Correct setting for these has the bolt all the way through the captive threads on the sway bar.  If you actually need  more tension than this gives you (again no more than you can tighten with two fingers on the lever), you need to tighten the adjustment bolt at the bottom a quarter of a turn at a time.  You may need to do this after you have a few seasons on your sway bar.  According to my instructions, it is preset for 1300 psi of tension when tightened up top.
 
(Why I am so specific about the tension)  I've actually tightened my sway bar so tight, I couldn't get it loose.  I got it off, put it in a heavy duty vise with a sledge hammer, and couldn't get it loosened.  Finally, took it to an RV shop, who did everything I did with the inclusion of a torch and finally got it loose.
 
Regarding the aerodynamics.  I didn't tow this with a pickup prior to the Tahoe, but I would rule out the aerodynamics.  The bed of a pickup truck is treated as solid surface by the air.  That's why having the tailgate closed is more fuel efficient than leaving it open and forcing air through the bed.  Air passing around the vehicle gets pulled into the gap between the trailer and the TV, that's why your rear windows get so much filthier with the trailer than they do normally.

[BaysideBruce]

Thanks for the suggestions.  I took the sway bar apart last night and put the wire wheel from the benchgrinder on it.  All this time I had been tighten the sway bar the way the dealer showed me... which was wrong.  I thought the "lever" is what you used to adjust the sway bar.  Actually the lever is just the on/off mechanism and the bolt below it is what makes the adjustments.  I tighten the bolt a 1/2 turn and plan on taking the trailer out for a test run this weekend.  Thanks for pointing out the right way to make the adjustments to the sway bar.  That might have been the problem!