Dual Cam setup

[NCMODELA]

So I set up the dual cam last year. the truck rode great. the only issue was some sway during wind gusts, large trucks or line of cars passing and some bouncing from the rear end. I just put new lt tires on the car. The first trip out this year it seems like the trailer is pushing the car to the left or right. it seems to get when when going through a curve. Driving 60-65 expressway is good except the occasional push. No more bouncing and little sway. Driving on the back roads at 40-45 is bad. I feel like im getting pushed all over the place. It was not like this the last year at all. it was a dream to drive on the back roads. I did notice that the dual cam lobes has shifted a little bit and was wondering if this could be the issue. I had read somewhere on here that if the lobes were not perfect it was a nightmare to drive. Below are some pictures of the setup when the truck was in a straight line. It s a 03 Yukon xl pulling a 2011 26' keystone summerland
https://lh3.googleusercontent.com/-Vle0F30ZE-g/U06ALhnwwvI/AAAAAAAAAHY/cX9sDRPC9aA/w1152-h648-no/20140415_164551.jpg

[NCMODELA]

So I adjusted the dual cam and took it out and it ran much better. Upped the air pressure in the front and it took some more of the wiggle room out. I still have to play with it but at least I am not driving with two hands going back and forth.

Upon reading some other posts too, I am towing with brand new slightly agressive tires with less than 200 miles on them. My wife just took the yukon to chicago and should put on at least 2000 miles on them so lets see if that takes some of the squirm out too.

[JBarca]

NCMODELA wrote:
Does this also apply to running them on a unloaded vehicle too? I was running them at 35 unloaded and that is what I was running the other rated ones at.

I do not know for your tire what the minimum inflation pressure is. You should consider calling the manufacture and asking for customer service. You have a LR E tire made for 80psi, running it at 35psi is more than 50% of the max pressure. That may or may not create issues. There is for sure a load part of this, but the tire may have other issues being that far down the pressure range.

I tried to find a tire pressure chart on your tire and I cannot find one.

Goodyear has one for Goodyear tires. http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf If you scroll down to the LT's, you will see a load verse pressure for the size. They do stop at 35psi for their tires. This seems to point to a minimum for a tire rated that heavy.

You for sure have to have enough pressure for the load, just there may be other concerns on that type of tire going down in pressure regardless of load.

I would check this out before you run that low very long. 35 psi on a 80 psi tire is not much. I have never run one that low. It may be OK or not.

Hope this helps

John

[NCMODELA]

Does this also apply to running them on a unloaded vehicle too? I was running them at 35 unloaded and that is what I was running the other rated ones at.

[JBarca]

NCMODELA wrote:
They were falken sport from discount tire.

http://www.discounttire.com/dtcs/findTireDetail.do?ra=filterTireProducts.do&fl=&tc=FALVL3&c=9&pc=18280&ar=75&rf=true&rd=16&rc=NCRINT&cs=265

LT265/75/15 E. They are a slightly agressive highway tread. The trailer tires are maxed at 50 psi cold. We used to run general grabber 265/75 15 at 45 psi (i think or whatever the max was) in the front and rear.

40 or 45 psi is too low for towing stability on a LT E load range tire. They have to have more air in order to create the more stable side walls. This is part of your problem or will be when bad conditions come at you. The tire pressure experiment will help. You have to find the sweet spot of not so hard the truck bounces to having stable side walls. This has happened to many others going from P to LT not realizing they need to add the extra air to get the benefit of LT's. And in some cases, one brand LT E to another brand LT E. I had that problem on my K2500 Suburban. All LT tires are not created equal.

Good luck and report back how you make out.

John

[NCMODELA]

They were falken sport from discount tire.

http://www.discounttire.com/dtcs/findTireDetail.do?ra=filterTireProducts.do&fl=&tc=FALVL3&c=9&pc=18280&ar=75&rf=true&rd=16&rc=NCRINT&cs=265

LT265/75/15 E. They are a slightly agressive highway tread. The trailer tires are maxed at 50 psi cold. We used to run general grabber 265/75 15 at 45 psi (i think or whatever the max was) in the front and rear.

[JBarca]

NCMODELA wrote:
The biggest notice was in the turns but it seemed like the whole system was slightly destabilized. I went from p to LT E tires and this was the first tow. 40 front 60 rear. I dont ever remember last year those cams being way off like that. that is why I was asking abou them.

Could the tires do it?

40psi in LT E tires can create unstable towing. In the truck it feels like the back of the truck just shifted but the problem can be the front end.

LT tires, jsut like P tires need air pressure to create a stiffer tire. LT's that low in pressure pending brand can be sog city. You can only gain the benifit of the stiffer LT tire by up'ing the air pressure.

By experiment.... keep up'ing the front. I woujd say start at 55psi and keep going up in 5 psi moves until it is so hard the front of the truck bounces, then back down 5 psi.Each truck brand and suspseiong react diffetent as well as the brand of LT tire.

You amy find that you need ~70psi rear and 60 to 65 psi front to create a stable truck.

The DC needs to get adjusted and the tire pressure needs to be optimized as a place to start. After that, we can still drill deeper in WD setup.

The DC cannot hold the truck stable if the tires on the truck are soggy.

Also, are the trailer tires aired up to max side wall cold pressure?

What brand LT tires and size did you get?

Hope this helps

John

[NCMODELA]

So could the new tires of knocked the lobes off of center? So it may not be the tires but the ripple effect of the new tires.

[APT]

NCMODELA wrote:
Ok. Thank u for the comments. Would thus be causing the issue I am having?

It certainly could be. I bought my TT and had the dealer install/adjust my Reese dual cam. First trip was into a thunderstorm where we could only drive 40mph due to visibility at times. It handled very well. A couple months later I replaced the tires, slightly smaller back to stock size. Next trip was a nightmare at 60mph when it was stable at 75mph before. A WDH adjustment to get those cam lobes centered restored the stability.

[NCMODELA]

The biggest notice was in the turns but it seemed like the whole system was slightly destabilized. I went from p to LT E tires and this was the first tow. 40 front 60 rear. I dont ever remember last year those cams being way off like that. that is why I was asking abou them.

Could the tires do it?

[mrekim]

NCMODELA wrote:
So I set up the dual cam last year. the truck rode great. the only issue was some sway during wind gusts, large trucks or line of cars passing and some bouncing from the rear end. I just put new lt tires on the car.

Are these tires a different brand or load rating. What PSI are you running when towing and what is max PSI of tires?

NCMODELA wrote:
The first trip out this year it seems like the trailer is pushing the car to the left or right. it seems to get when when going through a curve. Driving 60-65 expressway is good except the occasional push. No more bouncing and little sway. Driving on the back roads at 40-45 is bad. I feel like im getting pushed all over the place.

So is it really that turns are the main problem?

NCMODELA wrote:

It was not like this the last year at all. it was a dream to drive on the back roads. I did notice that the dual cam lobes has shifted a little bit and was wondering if this could be the issue. I had read somewhere on here that if the lobes were not perfect it was a nightmare to drive.

We recently had to reset the DC in the field. I drove for about 100 miles, mostly on an interstate, with one of the cam arms mis-adjusted by 1 and 1/3 turns of the adjusting nut. This was enough to obviously see when walking by. Towing seemed fine.

[BarneyS]

jimski3456 wrote:
Also it appears your chains are not vertical. This may have been caused by some slippage of your large u-bolt brackets thereby causing the cams to not be centered properly & thereby causing your sway issues. I have same system with the older style large u-bolts & I have to occasionally adjust do to slight slippage. After getting your cams centered, try to get chains as close to vertical as possible by adjusting lift-up brackets. Your propane tanks may be in way & some off-centeredness is OK. Others may know how much deflection is OK.

As long as the off vertical chains do not pull the cams back there should be no problem as all the chains do is hold up the cams. This is not the case in a normal non Dual Cam hitch where they should be vertical because of chain swing back and forth when turning.

I agree that his problem is probably caused by the cams not being centered on the V of the bars and that this situation was most likely the result of the cam mounting brackets slipping on the A frame. This is a common problem with the older style Dual Cam system. Those large U bolts must be checked frequently as they seem to stretch and loosen up a bit allowing the bracket to move.
Barney

[jimski3456]

Also it appears your chains are not vertical. This may have been caused by some slippage of your large u-bolt brackets thereby causing the cams to not be centered properly & thereby causing your sway issues. I have same system with the older style large u-bolts & I have to occasionally adjust do to slight slippage. After getting your cams centered, try to get chains as close to vertical as possible by adjusting lift-up brackets. Your propane tanks may be in way & some off-centeredness is OK. Others may know how much deflection is OK.

[DustyR]

NCMODELA wrote:
Ok. Thank u for the comments. Would thus be causing the issue I am having?

Yes, as both bar/sockets are attempting to be centered up, which is the path of least resistance.

As indicated earlier something has changed on your setup.

[JayGee]

That would at least be some of the problem. The resistance caused by the bar riding over the hump is what combats trailer sway. Your bar recess or arch is already off the hump and is unable to perform as it should. In fact, the when you turn and one bar falls on the hump properly it wants to stay there and will resist getting truck and trailer back into a straight line.