Trailer "fishtailing" ?

[Dawg]

I tow a standard trailer(see sig) with an EZ Lift type hitch. I have towed for many miles with no problems. I recently made a couple changes to set-up and now the trailer fishtails at freeway speeds. It is not constant, but is most apparent when the roadway is bumpy or in otherwise poor condition.

#1 Change, went from a Les Schwab TXR 265 load range 'D' to the 265 Revo load range 'E'

#2 Change, welded a 2" receiver to the frame of the trailer so that I can carry 4 bicycles on a rack. The rack protrudes out just past the spare tire so the first bike clears it nicely. The spare is mounted to the trailer rear bumper.

Would any of these changes make a difference in handling? Again, I have had no problems prior to the changes. I could tow up to 75mph with NO fishtailing. (I don't make it a practice of towing at that speed)

The only thing I can think of is the 4 bikes hanging off the rear of the trailer takes too much weight off the tongue. I don't know how much the bikes and rack weigh, but there is a lot of leverage from the last bike to the rear axle of the trailer.

I was going to weigh trailer tongue with the bikes on the rack and again with the bikes off the rack and see what the weight difference is. If it is a fair amount of weight, I will also have to consider the weight is doing a lot of bouncing up and down, which might be enough to lighten the trailer tongue and cause the fishtailing.

Sorry this is so long. Any input would be appreciated.

[DMAX LEGEND]

Dawg, Double check your trailer tire pressure. This happened to me once, and turned out one tire on rear axle was low on air.

[kerry witherspoon]

air presure could do it but low tounge weight will also do it tow it without the bikes and see if it makes a diference.

[tanker]

Dawg, I agree with Kerry, about the tongue weight. Weigh it with and with out the bikes. Adding additional weight to a trailer is ok if balanced. The longer the trailer length, the longer the fulcrum arm. (remember phyics in high school :rolleyes: ) or the see-saw in the playground. Four bikes + heavy rack + receiver etc. out past the rear bumper could do it. You may have been right on the money prior to this installation, then this started lifting the tongue.
One other item often overlooked is how level the trailer and tow vehicle are when hitched. Park on level ground and measure from bottom of trailer frame to ground at both the front and rear, it should be the same. The tow vehicle should also sit level. If not one axle in the tandem, or tridem will be carrying more weight which will cause sway, and cause bearings to heat up, plus tire wear.
Check axle alignment from time to time, if they shift you will have trouble. Just a quick check of the axle center to center measurement at the end of each axle with a tape measure. Should be the same on right and left. smile.gif

[Turbine Doc]

It's also possible the new tires are somewhat taller changing height of hitch, combined with the bike weight on rear will effect towability of the trailer, I had same problem on my trailer; the trailer pulled great behind my 1/2T gasser, behind the 1/2T Diesel it fishtailed.

The Diesel is just a little taller than the gasser, I put a 2" drop hitch instead of the straight hitch resulting in more tongue load and corrected the fishtail.

[Kennedy]

Move some of yourcargo forward. Preferrably something permanent. Tongue weight needs to be MINIMUM 10% of total. More is better

[rjschoolcraft]

As many others have said, the extra weight out back is probably the culprit. I added a receiver hitch and home-built bike rack to haul six bikes on the back of my trailer. I always make sure to haul some of our "permanent" cargo in the front of the trailer when doing this to keep the tongue weight balanced and keep the fish-tailing from happening.

[99gmccrew]

I'm no expert on this subject, but are your new tires designated trailer rated tires. I've seen people that have had passenger car tires on their trailer which caused fishtailing.

[moondoggie]

Good Day!

Trailer Life has long recommended 10 - 12% of total trailer weight on the tongue for tag-along trailers. I'd guess you could go over that by some & suffer no adverse reactions, other than too much weight on the back of the tow rig. Too little is guaranteed to cause sway

[Dawg]

Thanks everyone. I thought I was on the right track. The new tires are the same size and are truck tires. The truck drove great, I was able to see the fishtailing in the side mirror. It is not terrible but I had zero fishtailing prior to the rack.

I will weigh the tounge as previously stated and will do some test towing. I checked all the tire pressures and they were all good. I will measure the center of the axles just for piece of mind. If the tongue is light I will look at carrying some water in the fresh water holding tank. IIRC it is mounted largely forward of the front axle. I will advise of my findings. Thanks again!

[moondoggie]

Good Day!

TIA for keeping us updated.

If you've ever talked to someone who had a fishtail go beyond what you've seen, I think you'll find that this is something they have zero tolerance for. :eek: Personally, if I get ANY wiggle, I fix it, because of what I've heard from other folks who've had it escalate.

Blessings!

Brian Johnson, #5044

[99gmccrew]

Someone please correct me if I'm wrong, but there is a difference between truck tires and trailer tires. I was told buy the tire shop that I bought my trailer tires from, that I had to buy special trailer tires because they track better than normal tires.
For this reason I had to wait an extra day because he had to order the tires. My trailer pulls straight as an arrow.

[Kennedy]

Most 16" E rated are truck tires anyhow.

My opinion (just opinion) is that the ST series of tires could well be CHEAPER as thaty are not rated for automotive use therefore aren't under as much liability, and testing restriction...

[rjschoolcraft]

I've read that the main difference is in the formulation of the rubber compound. ST tires are formulated to resist UV breakdown better than truck tires. I've also read that the sidewalls are different to help resist sideward roll when in tight turns.

Heavy trailers requireing "E" tires are equipped with LT tires from the manufacturer.

[CareyWeber]

Originally posted by 99gmccrew:
Someone please correct me if I'm wrong, but there is a difference between truck tires and trailer tires. I was told buy the tire shop that I bought my trailer tires from, that I had to buy special trailer tires because they track better than normal tires.
For this reason I had to wait an extra day because he had to order the tires. My trailer pulls straight as an arrow. Dawg did not say it, but I think the tires the he mentioned are on the truck not on the travel trailer.

265's won't fit on a travel trailer.

I have a set of 265 LR E Revo's on my K3500 and I like them.

Carey

[Dawg]

Yes, the new tires are on the truck. Same size just a load range heavier. The trailer tires are the original set and have worked great.

[99gmccrew]

Sorry I misunderstood, my bad.

[Dawg]

I will say I think the Revo's are great. They are very quiet and ride very smooth and have excellent traction. I highly recommend them.

[Dawg]

I towed the trailer to a nearby scale house. The scale had the dial indicator type readings. It was a little hard for me to see the face of the scale through the door. The scale was in 50lb graduations. It was hard to read but I know I'm
within +/- 50lbs. It looks like the tongue is a little light with the bikes on the rack. Probably compounded when bouncing. The trailer was pretty much in the same condition as being on a trip, except for food and beverage in the fridge(front) and clothing items in the bedroom(rear).
What do you all think? Looks like more weight in needed on the tongue.

Steer 3800 Rear 3750 Trailer axles w/bikes 5600

Steer 3800 Rear 3800 Trailer axles w/o bikes 5450

Truck disconnected from trailer;

Trailer tongue 600 Trailer axles w/o bikes 5400

Trailer tongue 550 Trailer axles w bikes 5600

Thanks in advance.

[HowieE]

From these numbers I see you do not have a weight distributing hitch. You are acutally removing weight from the rear axel when the bikes are on the trailer and getting very close to the 10% rule for tongue weight.
First thing I would do is put 300 lbs in the back of the truck and try it with that load while the trailer and bikes are on. If this corrects the fishtailing you need to get the tongue weith higher and consider a weight distributing hitch. This type of hitch will transfer some of the tongue weight to the front axel of the truck and hold the towing vehical to the road.
A general rule when loading a truck with a trailer is to have the front axel drop about 40% of the drop in the rear axel as measured across the center line of the wheels to the fender edge. If the front remains the same or goes up you will see fishtailing.

[DMAX LEGEND]

I agree with HowieE, You're below the magical 10% with the bikes, 5600+550. Total tlr weight is 6150. Tounge weight is 8.9%, too low. You need to get it up to about 12% or somewhere around 750 lbs. A little extra won't hurt anything. You could simply move things from the rear of the trailer to the front or add weight to the front by filling holding tank or similar fashion. I also would get a weight distributing hitch, they're the way to go when towing over 5000# with a ball hitch.
My $0.02
Paul

[moondoggie]

Good Day!

HowieE said:

[Dawg]

I use an EZ Lift set up with the two torsion bars and an anti-sway bar. Is this the weight distribution hitch you guys are speaking of, or am I missing something else? I'm not an expert, that's why I am asking you folks who have much more experience than myself. Your help is much appreciated.

I will add water to my fresh water tank on our next trip. The tank is in front of the axles. I bet this will correct the problem. We normally run with the tank empty. It will be a while, but I will also make a run without the bikes and rack and confirm the bikes and rack are the cause. As stated prior, no problems until I added the bike set up. I would also like to weigh the tongue with the water in the tank. Thanks again and I will report back after the next trip.

[HowieE]

The reason I commented that it looked like you did not have a weight distributing hitch is because the weight you posted do not reflect any weight distrubution. If your trailer has a 600# tongue weight I would expect most of that to show up in the rear axel weight. You posted rear weights of 3750 w/o trailer and 3800 w trailer, only a 50# increase. I would have wxpected the rear weight to go up by at least several hundred lbs. You also posted no increase to the front axel when the trailer was on. The hitch should have thrown some weight forward.
Here are some of my old weigths, from my 87 Sub with a 26ft. trailer, that reflect what I am saying. I do not have a tongue weight for that trailer but it makes no differance to the theory
Truck
Front 2460
Rear 2580

Truck with trailer
Front 2520
Rear 3060

With my current trailer I try for 150 to 175# addition to the front axel when setting up the hitch.

If your hitch was providing the intended effect it may have been more effective to have weighted the trailer for the experiment but yor idea of water in the front of the trailer will deminstrate the same thing.

On larger trailers that have tongue weight over 500# a weight distributing hitch actually is used to reduce the total rear axel weight, dry weight + tongue weight, and increase the weight on the trailer axel and front axel of the truck. With this distrubution of weigth you then change your tire pressures to reflect the weights. You can find tire pressures per axel weight on most tire company web sites. These increased tire pressure and increased weights per axel should correct for most sway. However in very long trailers or trailers with a high flat wall should also have a sway control device.

[Dawg]

I went back to the scale house today and took the weights of the truck. About 1/2 tank of fuel and 200lbs of "stuff" in the bed of the truck which I normally carry.

Steer 3900 Rear 2950

[Dawg]

Update 7/12.... I filled the fresh water holding tank for this trip. No more fishtailing. Problem solved! Thanks everyone! The one thing I will replace in the near future is the OE shocks. I have 37,000 miles on the them and they are junk!

[sonofagun]

Dawg,

One final note. You need about 188# more weight on the hitch to get to the 12%. I would go for the number rather than the feeling that all is ok. If you get into a bad situation that would cause serious fish tailing and you were on the line (therefore ok normally) it could prove difficult. Also check to be sure that your torsion bars are properly adjusted. HowieE is right, you should be seeing more than a 50# increase when hitched up.

Good towing,
Bob

[Dawg]

How can I determine if the hitch is adjusted properly?? I'm new to this type of set up.

I have the torsion bars hooked on 4th link(3 dangling)

When hooked up, everything looks level. Torsion bars look to be parallel to the ground. If I go one more link on the torsion bars, would that shift more weight to the front?

Thanks for all the help!

[DickWells]

Dawg: I wish I had your problem of too little tongue weight. I have a trailer that sounds about the same as yours, stock. But, last year, I extended the tongue to make room for a Quad Loader(300 lbs), plus ATV (800 lbs), plus the extra steel (300 lbs). I ended up with a trailer that weighs about 7000 lbs and has a tongue weight of 1420 lbs. The good thing is, that I still have a trailer that handles well.
I have 1200 lb dual cam bars in place of the 600 lb bars that I used to have.
I trailered over 5000 miles on load range C tires on the Sub. before I changed to LR E's. (always Michelins - 265 75's)
I trailered over 3000 miles before I put air bags under the Suburban.
Anyway, to sort of answer your question about the attitude of your torsion bars: I wouldn't be too concerned about the bars being parallel to the road. Not knowing the size of your bars, I can't be totally sure, but if you make your adjustable ball mount so that the height of your ball socket makes the tongue (trailer) level on level ground when the weight is on your tongue jack, then adjust your tension on your chains to make the trailer level when you transfer the weight off the jack to the back of your horse, then theoretically, you should be right for the road. With your light load, you might want to raise your ball mount a notch to take some more tongue weight innitially, before the bars are hooked on. This might help your fish-tailing without hauling all that water around. Your adjustable ball mount is probably ajustable for the pitch of the front torsion bar pins, too. By taking out the big cross bolts, you can change the washer stack under the bar pivot boss and thus change the pitch of your bars to keep them more level with the road. Just study that ball mount for a couple of minutes, and you'll see what I mean.
I'll bet you can compensate for any added weight back on that bumper, by carying some of your every day stuff up front in the trailer, and less fresh water, just by fooling with your hitch. Otherwise, the 12 to 14% tongue weight is the correct thing to shoot for.
Good luck.
Dick Wells
P.S. Don't let any dealer tell you that the dual cam bars are overkill for a light trailer. I'll never be sorry I have mine. I've towed in 50 mph + gusts without problems. Hard to immagine what it would have been like if I had settled for the epuipement that some trailer dealers tried to stick me with back when I was shopping for trailers and hitches, etc.

[Dawg]

Dick,

I think you might be onto something. The torsion bars are marked 750lbs. By looking at my tongue weights posted above, there is not near that amount on my hitch. In fact, when I hook up the chains and and cam them up, it just doesn't take much effort. I can adjust the height of the ball and I can see where I can adjust the pitch of the ball. Are you saying that I should raise the ball height 1 hole? In the past I have tried to go one mare chain link. (5th link, 4 dangling) The 5th link of the chain could not reach the hook. Guess I got more work to do! Thanks again.

[ropinfool]

In regards to tires, at the dealership I worked at, we recommended going with the LT series vs. ST. Price and availability were the major factors. Our larger trailers came with LT's from the factory anyway so why not put them on the smaller trailers? We called the manufacturers to verify it would not "void" anything with them and was told go ahead. When I bought my trailer it had P rated tires on it, I went with LT's. Of course we always had a couple of people who would not buy anything but the ST's, no matter how much money we could have saved them. Just my 2 pennies. John

[DickWells]

Hi Fellas: I read a lot of good info here in the DP. I agree, John, if I could find a higher load rating for my trailer, when I needed new tires, I'd buy them. My feeling is, that you could run the minimum air pressure in them, to keep from shaking your trailer too much, and reap the benefit of having stronger casings and tread.
Dawg, since you don't have the dual cams, I don't think you'd have to be concerned, but with me, if I don't transfer enough weight to the front of my Suburban, I can get aquaplaning in really heavy rain. Conversly, if I was pulling on snow or ice, I used to have to slack right off on my torsion bar load in order to get pulling traction. With 1400+ on the tongue, now I don't have to worry about that.
Yes, I'd guess that you could pick up some tongue weight by raising your adjustable ball mount one notch. You'll have to play with the tilt in your vertical bar pins to get the right amount of load transfer. With your light tongue, it should be easy to transfer too much weight through your Suburban frame to the front wheels. You'll need to experiment to find out what's ideal. You should be sitting level between the horse and the trailer, while sitting on level pavement. I still find it hard to believe that you can't get 12-14% of your trailer weight onto your tongue with a stock trailer with just a couple or three bicycles on the back. Still, I just read last month in one publication, about a toy hauler that was set up such that if you put the toys in the back that it was rated for, you could just about lift ALL the weight off the tongue! Now that would make one mean handling trailer! You wouldn't think that any manufacturer would market a product that would do that. Sort of reminds me of my Quad Loader that I use for a platform on the extended tongue of my trailer. The unit itself is rated to tow 1100 lbs, yet the single tire that comes with it is rated for 780 lbs, max.
I always meant to call them about that. Yep. That and some other things, like the wheel bearings being adjusted so tight at the factory, that I had to stop in the first seven miles, unload my ATV, flip the Quad Loader up, and adjust those bearings. They were about 4 castleations beyond tight! And I was about as hot under the collar as those bearings.
Keep fooling with your set-up, and let us know how you come out.
Good luck.
Dick

[HowieE]

Dawg
Would you go on my web site the bottom of the first page and e mail me I think I can help.

[dieselrealtor]

I don't know what kind of traveling you do, but for me I am planning on adding a 2nd battery next spring for longer 12v capacity. :D

[raypete]

diesel realtor
Don't just add a battery, put in 2 matching units. Go to 2 6v golf cart batteries for much more battery life. For more details contact me @ raypete@ejourney.com.

Ray H. Peterson