Bad handling TT

[grassy]

Folks,

I have a 25 foot ultralight Shamrock Hybrid.  It has a great layout. We love it.  It is @ 4200 pounds.

I have a RAM hemi 5.7 with air bladder shocks.

We have a load stabilizer and anti sway bar.  We put new tires on the trailer.

At 105 KMS (@ 64 MPH) with no noticeable wind, it  starts to noticeably stay...much higher it becomes a handful.  In the wind...I get arm pump...The proceeding additions were done at my dealer's suggestions...

I am beginning to believe I was sold a trailer with a problem...

Any suggestions or comments ???

Thanks
Ian

PS - gearing up for a long trip next month..

 

[Shayne]

Some states have a 55mph max for pulling trailers in the 1st place  so the lower speed would assist you.  It's safer too.

 

[Ron]

There are a few things that can be responsible for the conditions you have described.  Are you within your vehicle weight limits on both truck and trailer?  Are all tires properly inflated per tire manufactuers inflation charts for the load?  Is the trailer properly loaded?  If the answer to any of these questions is no then that could be the problem.  Have you had the trailer tire alignment checked?

 

[grassy]

Hi,

The speed limit  for us on the highway is 110 kms and most people usually do about 10% over so 100-105 works well..we are not holding up too many big lines of folks who are in a rush  ..as well, because we are on a schedule, we have learned that a 15 KM per hour difference really adds up to a lot of time.

Yes...the correct air pressure in both the truck and trailer.  We carry very little in the trailer except for food (over the axle) and my son's mx gear.

I had wondered about alignment...I have never seen anyplace that that could be done...is there a test to check ?

Thanks
Ian.

 

[Carl L]

Okay, your truck should be adequate to pull that trailer.   I suspect that your problems are going to center around the tongue weight of the trailer and the adequacy of your weight distribution.   You can start with either first but I will deal with weight and then weight distribution.

Weigh your trailer at a public scale -- see our library for the procedure.  Click HERE.   Pay particular attention to the tongue weight.    It should be at least 10% of the total weight.   It can be as much as 15-17% but the 10% is critical.  If it is too light, consider moving cargo from the rear to the front.   If your fresh water tank is ahead of the trailer axles, fill it.

By "load stablizer" I assume you mean a weight distributing hitch system.  What brand and model did the dealer sell you?   When you initially hitch up the trailer, the rear end of your truck should sag under the weight of the trailer tongue (you are in trouble if it does not).   For proper control of the tow vehicle during motion, the tow weight of the traler must be redistributed equally between the front and rear axles.  We have a procedure in the library for adjusting the hitch so that it does.  Click HERE.

There is a company called Sherline that puts out a hydraulic scale that measures tongue weight directly.  I recommend it.  The also have an excellent freebie online guide to trailer stability.  Click HERE.

 

[grassy]

Carl,

the truck is not a problem..load more power than my last RAM.

Will have to find a scale around here...shouldn't be a problem.

I was told when I bought the rig that the tongue weight was 375...less than 10% of the trailer...I am now wondering if they actually knew the weight or just guessed..

>you mean a weight distributing hitch system

Yes, it is a Husky good for 600 to 800 lbs...the dealer mentioned that it was better to go bigger "just in case" we outgrew this trailer and we could just use less chain...he was more concerned about the ride...we have 3 free links..

Our water tank is a back corner..not good for weight dist.we normally run with it empty..

It sounds I should go back and have a heart to heat with my dealer ?

Am following up on the other...

Thanks
Ian.

 

[Gary RV_Wizard]

The tongue weight they quoted was probably the dry weight, i.e. for an unloaded trailer with no propane and water.  You want it to be 10-15% (I like 15%) of the actual loaded trailer weight for good road stability.

I suspect you are doing yourself a disservice if you only load things over the axle - put some of that food and gear up front and let it weigh the tongue down a bit.

 

[grassy]

So the stability of the trailer...ie - the trailer will follow in a straight line vs we-wawhing all over - is based on how much weight is on the tongue ?

Thanks
Ian.

 

[Carl L]

So the stability of the trailer...ie - the trailer will follow in a straight line vs we-wawhing all over - is based on how much weight is on the tongue ?

Thanks
Ian.

It is one of the things and a big item at that.  It is a measure of the position of the center of gravity of the trailer.  If the CG is well forward, the leverage of the trailer over the truck is reduced.  Think of holding a weight on a pole.  If the weight is way out on the end of the pole it requires a lot of strength to hold it and if it starts to wobble it is hard to control.  However, if you shorten the pole, the weight becomes easier to hold and control.  Same thing with the trailer.  Low tongue weight, CG way back and the trailer is hard to control.  High tongue weight, CG well forward and trailer control is easier.

My 23 footTT weighs 4600 lbs and has a tongue weight of 750 lbs as scaled.  That is 16%.  I have a stable trailer.  A 4200 lbs trailer should have a TW of between 420 and 630 lbs.    375 don't make it.

 

[Gary RV_Wizard]

So the stability of the trailer...ie - the trailer will follow in a straight line vs we-wawhing all over - is based on how much weight is on the tongue ?

It's the largest single factor and far and away the most likely source of your problem. Axles can be out of line or the frame crooked, but it is not common.

 

[Carl L]

Yes, it is a Husky good for 600 to 800 lbs...the dealer mentioned that it was better to go bigger "just in case" we outgrew this trailer and we could just use less chain...he was more concerned about the ride...we have 3 free links..

Husky?  I was not familiar with the brand so a Googled it.  Husky is a brand of 5th wheel hitches, not travel trailer hitches.  Could you check the brand again?

Also three links means little here.  Does the current setting restore the unloaded attitude of the truck?  Since you have a real problem of stability, it would behoove you to check that attitude with the tape procedure described in the library article on adjusting a WD hitch.  Your spring bar setting should restore the relative height of the front and rear fenders to within 3/4" resolving ties in favor of weight on the front axle.

 

[Johncmr]

Good thread. 

I had a thought.  Some trucks are sold with light weight tires, or when replaced, folks don't realize that the side walls on the tow vehicle need to be rated at "B" or "C"  which I believe is the strength and rigidity of the side walls. 

Tire structure on the tow vehicle has caused me problems in the past.

Johncmr

 

[grassy]

Not to be argumentative, but it says Huskly load bearing hitch on it and the two bars...I live in Canada so you may be looking at an American web site ?  I really wanted the load bearing hitch that had the sway bars as part of the unit (cannot think of the name) but it was nutzy expensive.

I am running 4 ply tires at the moment but I have had the same trailer towing problem with my last truck that had 8 ply...but I am in the load ratings.

>Does the current setting restore the unloaded attitude of the truck?

Good question.  Yes.

Visited my RV dealer today and had a chat.  The don't have a gizmo that does tongue weight so they have ordered one.  Also, they  suggested a scale that could do my length..I will have to go out and talk with them.  The dealers  line of thinking at the moment is that the load leveler is too strong..they want me to take the trailer out on the highway w/o the LL and see what happens..from what you guys are suggesting, this may be the ticket.

Since I have air bag shocks, should I level the rig or let the "attitude" of the trailer point down...always thought that that put extra pressure on the leading tires..btw, none of the tire treads look off.

I really appreciate the help on this...we have a really long pull soon and I am starting to dread it.

Thanks
Ian.

 

[Carl L]

Not to be argumentative, but it says Huskly load bearing hitch on it and the two bars...I live in Canada so you may be looking at an American web site ?  I really wanted the load bearing hitch that had the sway bars as part of the unit (cannot think of the name) but it was nutzy expensive.

There are three:  the Reese Dual Cam, the Equalizer, and the Hensly Arrow.  The last is about $3K US.  The others are about $800 US for the ball mount, bars, and tongue hardware.  All are excellent.

I am running 4 ply tires at the moment but I have had the same trailer towing problem with my last truck that had 8 ply...but I am in the load ratings.

It is the sidewall plies that count in this, not the tread plies.  But tires do not seem to be the issue here anyway.

Does the current setting restore the unloaded attitude of the truck?

Good question.  Yes.

Did you eyeball it or did you measure?  The criteria is within an inch.

Visited my RV dealer today and had a chat.  The don't have a gizmo that does tongue weight so they have ordered one.  Also, they  suggested a scale that could do my length..I will have to go out and talk with them.  The dealers  line of thinking at the moment is that the load leveler is too strong..they want me to take the trailer out on the highway w/o the LL and see what happens..from what you guys are suggesting, this may be the ticket.

Overly strong.  Well that is not good for the health of trailer frame, but stability?  I would have to think about that.  Eliminating all WD is not going to help trailer yaw.  May I suggest you ask the dealer to take a short test drive of the trailer with you. 

Since I have air bag shocks, should I level the rig or let the "attitude" of the trailer point down...always thought that that put extra pressure on the leading tires..btw, none of the tire treads look off.

The object of WD hitches is to move some tongue weight on to the front axle to restore the normal understeer configuration of the tow vehicle.  You want a vehicle to plow slightly going into a turn -- not pivot about its rear wheels in an oversteer condition.  That magnifies yaw in the trailer and you do not want to magnfiy yaw -- trust me on this one.  8)    Let your spring bar adjustment corrent attitude, not air shocks.

I really appreciate the help on this...we have a really long pull soon and I am starting to dread it.

Better to sweat this out now than on a trip.

 

[King]

I bought a 25 ft sailboat, it came with the original factory supplied trailer. No sway system, no load levelers.  Boat and trailer about 5000 lbs.  The first trip, she started to sway at about 55 mph.  Any faster, and it got worse...  much worse.  I talked to a lot of people, and found about tongue weight.  IT didn't have any.  I could lift the tongue with one hand.  I couldn't redistribute any weight in the boat.  I had the spring mounts and fender mounts welded to an angle iron bolted to the frame so I could move it at will.  I moved the axle back one foot.  After that I could travel at any speed I was comfortable with and the trailer stayed straight on behind.
Art

 

[Shayne]

Proper Balance is an amazing thing when it's right. Pain when it;s off.

 

[grassy]

>It is the sidewall plies that count in this, not the tread plies

Since the 8 ply are usually heavy duty tires and can carry heavier loads, sidewalls are usually heavier than in the 4 ply but I agree with you.  This isn't a tire issue.

So i did the easy to understand to do instructions for adjusting my weight distributing hitch. BTW,  was looking at the equalizer and 800.00 is very expensive....hence the husky which does the same thing except for the sway...

My truck (with 10 pounds in the bags) sits at 39 10/16 (rear) and 37 9/16 (front) w/o trailer.  With the LL on the 4th link my measurements were 38 1/2 and 37 9/16....with the lightest (2nd link) I am at 38 1/4 and 37 9/16. I cannot physically move to the 5th link.

If I understand this excercise correctly, my LL is not strong enough because I cannot get within 3/4 inch.

I also ran it w/o the bars (and with the sway bar)..at 110 KMS she started to sway bad enought that I slowed down..

I dropped by my rv store and they suggested that my hitch isn't set up correctly ????

What should have been easy doesn't seem to be..

Thanks
Ian.

 

[campers4u]

was looking at the equalizer and 800.00 is very expensive..  wow,,,, knock off 300.00  and thats where it should be

 

[Carl L]

was looking at the equalizer and 800.00 is very expensive..   wow,,,, knock off 300.00  and thats where it should be

He is Canadian, those could be $CDN.

 

[Carl L]

My truck (with 10 pounds in the bags) sits at 39 10/16 (rear) and 37 9/16 (front) w/o trailer.  With the LL on the 4th link my measurements were 38 1/2 and 37 9/16....with the lightest (2nd link) I am at 38 1/4 and 37 9/16. I cannot physically move to the 5th link.

If I understand this excercise correctly, my LL is not strong enough because I cannot get within 3/4 inch.

My arithmetic says that your original attitude,  front minus rear measurement, was +2-1/16 inches.  At link #4 the attitude was +1-15/16.    The difference from the original attidue was 2/16 inches.  That is with in the 12/16 (3/4) inch tolerance.   Based on bar adjustment, you should be ok.

I also ran it w/o the bars (and with the sway bar)..at 110 KMS she started to sway bad enought that I slowed down..

Yup, one might expect that to happen.   That is why WD, antisway hitches were developed.

I dropped by my rv store and they suggested that my hitch isn't set up correctly ????

That could be quite true.   The ball mount has to be tilted at the proper angle to position your spring bars when loaded.  The procedure for your unit should be in the instructions.  Read them.   Discuss with the installing dealer.   We are talking bolts that require 200-300 pound feet of torque.  That is a lot of torquing for amateur tools.

We are also skirting around what might be the heart of your problem, your tongue weight may well be too light for any hitch system to handle.   Get weights.

What should have been easy doesn't seem to be..

Boy howdy.  Unfortunately I live in Los Angeles and I cannot do what I want to do --- run over to your place and check out your tongue weight with my handy dandy Sherline scale.