Return to the Cars Forum | Post a Follow-Up

 o
Unstable trailer

Posted by worm (My Page) on
Thu, Apr 13, 06 at 8:42

Was pulling a 10 ft. landscape trailer (flat non enclosed trailer) with two motorcycles on it. When we got to about 55-60 mph the trailer started to go very unstable (side to side motion). It felt like it was going to pull the car right off the road. We've used this same trailer before with no problems. Only difference was we both got heavier motorcycles (went from total weight of about 1200 lb. to about 1500 lb.). We moved one of them back a foot to try to lessen the tongue weight from the heavier motorcycles a little bit. Somebody told me that instability was caused by too little tongue weight. Does anybody have experience with this? What causes the trailer to go unstable and how do we fix that. It's not fun driving 50 mph on a 1000 mile trip. Air pressure in the tires is fine.


Follow-Up Postings:

 o
RE: Unstable trailer

is there a difference in the aerodynamic shape of the bikes? Could this add to the oscillations?


 o
RE: Unstable trailer

Your total weight with the trailer must be about 1900 pounds. Therefore get your draw bar weight to about 160 pounds.

Make sure the center of gravity of your load is ahead of the trailer axle(s), Make sure the weight is centered sideways. Look at the suspension to see if a spring is broke or the spring shackles or tie rods (if any) are loose etc. Check the tire balance - just jack it up and do it by hand. Make sure tire perssures are even.


 o
RE: Unstable trailer

Increase the tongue weight to reduce the swaying. The more weight on the tongue, the more friction there is between the hitch ball and socket.


 o
RE: Unstable trailer

If all else fails, you can have an E-Z Lift sway control installed. Your trailer is lighter than these are typically used for, but it will stop the swaying for sure.


 o
RE: Unstable trailer

I pull an enclosed cargo trailer of the same size. When it starts swaying it's because you have too much weight on the back end of the trailer. So move the bikes either on or in front of the axle.


 o
RE: Unstable trailer

I pull a 20 ft. 2 axle trailer every day. If it is improperly loaded (too much weight behind the axles) the trailer will sway and control is bad. Agree, more tongue weight but do not exceed the hitch specs.


 o
RE: Unstable trailer

Between 60 and 75 persent of the weight should be on the tongue. You have figured out your problem by yourself by telling us what changed. you have over loaded your trailer.
an anti sway hitch will help but will eventually rip the
tires off your trailer. Your trailer and car become one
piece after the sway bars are installed. Get the proper trailer for your load or get a lot of extra insurance. you'll need it. Anti sway bars are a miss conception. they help to a point but were not designed for that. they are designed to level the tongue and the towing vehical. I can
get very nasty and rude when someone risks their life and
maybe someone else's when there is a real safety issue involved. You have one. I'm sure you will replace the trailer with the proper one or have it professionaly upgraded. This is NOT a D.I.Y. project unless you do this for a living. good luck. You can always get new bikes when the trailer and towing vehical part company and they will
if your problem is not corrected. Mind you i have seen both upside down in a ditch. No offence but i've seen
a few red flags in your post. John. The hitch and the hitch
ball have nothing to do with anything. People grease them to stop squeaks and if they use the hitch as a ground they
lose their lights. It's the geometery between the tongue
and the axle weight and length. The tongue length and axle
position of the trailer should be longer than the wheel base of the towing vehical some time shorter but not the
same. getting off topic but you know what i mean. I've built many a trailer and know what the poster means. Not fun. actually quite scary.


 o
RE: Unstable trailer

Just so there's no confusion, I was NOT refering to a load leveling hitch. Some of these type hitches by design, Equal-izer (brand) for one, have an anti sway feature built in. Most do not. I was refering to an add on device that can be used on most anything.

Don't know what someone was refering to when they said 60 or 75% of the weight should be on the tongue. The weight of what? If a travel trailer weights 8000lbs, there should be 6000 lbs of tongue weight? Don't think so.

I do agree that one should spring for a trailer designed to do the job you're wanting to do.

Here is a link that might be useful: sway control


 o
RE: Unstable trailer

mostlikely the poster was talking about 65-75% of the weight should be in front of the axels. tounge weight is a percentage of the balanced load. an 8000Lb trailer properly balanced will have about 450 - 800 lbs depending on the tounge design. actually, an 8000Lb trailer should be using a "fifth wheel" type tounge.
the problem whith the stated OP is as mentioned, too much load behind the axel. "heavier Bikes" probably closer to 1800Lbs and the foot back, puts the load too far back.
a 10 foot trailer really doesn't have enough room for two large bikes to be properly balanced on the axel. ya need another 2 feet to get the load right. I will bet the axel is also not heavy enough to support those bikes. get the load exact and determine the max load on that axel and I bet you get startled on both fronts.
tow safely,
John


 o
RE: Unstable trailer

You mention the weight of the bikes. I have no idea how much a motorcycle weighs. But if the trailer has only one axle it's maximum weight is usually about 2700-3000 pounds. Including the weight of the trailer itself. And an open utility trailer possibly weighs about 400-500 pounds.
So yes, an overloaded trailer can be troublesome.


 o
RE: Unstable trailer

ifn i go to boatus and search tongue weight
5 - 10 % of gross.
So for 1500 lbs gross that'd be between 75 - 150 lbs on the ball hitch.


 o
RE: Unstable trailer

We have pulled two motorcycles exactly like the ones we're pulling now before on this same trailer with no problems. Only thing that we did was move one motorcycle back about a foot because we thought the tongue weight was too much for the vehicle. I believe that was our mistake. This trailer is not overloaded. It has over 3000 lb. capacity. We're way below that. And there's no way we should have 60-75% of the weight on the tongue. In this case that would be 1500 lb. of tongue weight. The solution appears to be put the motorcycles back in their original position.


 o
RE: Unstable trailer

By the way...... the bikes are side by side on the trailer not end to end as I believe the one poster who said this trailer isn't long enough may have thought. The original position was side by side and as far forward as they can possibly go.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Cars Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here