Trailer swaying...

Discussion in 'Trucks and Trailers' started by inHaliburton, Jul 10, 2007.

  1. inHaliburton

    inHaliburton LawnSite Member
    from Picton
    Messages: 197

    I pumped up the trailer tires from 35 lbs. to 55 lbs. Now the trailer sways back and forth at speeds over about 40 mph.

    Tomorrow I'll be letting air out until issue is corrected.

    Any ideas why swaying occurs at higher tire pressures?
  2. LindblomRJ

    LindblomRJ LawnSite Silver Member
    Messages: 2,570

    How is the trailer loaded? Where is most of the weight and how is it distributed? What size is the trailer?
  3. inHaliburton

    inHaliburton LawnSite Member
    from Picton
    Messages: 197

    The trailer is 5 x 10 with the front wheels of the JD 737 about 2 feet back from the front of the trailer. Got to be at least 100 lbs. on the tongue.
  4. procut

    procut LawnSite Bronze Member
    Messages: 1,852

    Yes, check to make sure you don't have negative tounge weight.
  5. KTO Enterprises

    KTO Enterprises LawnSite Bronze Member
    Messages: 1,286

    Put the mower on the trailer backwards.
  6. The Captain

    The Captain LawnSite Senior Member
    Messages: 607

    Why are you running this much air pressure? The sidewall gives the maximum safe air pressure (usually around 35 psi). My first guess would be the tires can't flex up & down or sideways. Kind of like having wooden wheels on the trailer. You'll probably blow one of them when you hit a nice sharp edged pothole.

    KTO, what are your thoughts?
  7. SiteSolutions

    SiteSolutions LawnSite Bronze Member
    Messages: 1,114

    My trailer tires say 65 psi. My truck tires say 80 psi. 35 psi is for passenger car tires or small utility trailers, where you are putting about 1500 - 2500 pounds per axle, not per tire.

    That said, Captain is absolutely right that each tire should be inflated based first on what the sidewall says. If you've got tires designed for 35 psi on a smaller trailer, that's what you should run. If they say 50 psi, that's what you should run. If you're over or under, you can get all sorts of problems with handling, improper wear, blowouts, brakes not braking very effectively, and so on.
  8. inHaliburton

    inHaliburton LawnSite Member
    from Picton
    Messages: 197

    Appreciate all the feedback.

    The sideswall says to inflate to a maximum of 50 lbs., so I'm over a bit. They are Carlisle (sp.) trailer tires. The reason I increased pressure was to make it easier to pull with my Ford Focus. Ofg course, it pulls just fine empty at 55 lbs. but with the mower it's terrible. Swings me all over the road. I'll try loading it backwards, too. That'll put more weight on the tongue. I'll try your various suggestions tomorrow until I get things right.

    I may be pulling more weight than I should be. The mower weights about 1100 lbs. and the trailer weighs about 725, plus another 120 lbs. of other stuff.

    This is the trailer I'm running:

    Thanks for your thoughts.
  9. SiteSolutions

    SiteSolutions LawnSite Bronze Member
    Messages: 1,114

    I think we may have located the source of your troubles.

    A Focus has, as my neighbor puts it, "a bad case of noassitol" (no-a$$-at-all)

    That trailer weighs almost as much as your tow vehicle so it is going to manhandle it a bit... getting the balance right will be important.

    I think underinflation helps mask the problem by making the trailer drag a little bit, which would tend to keep the trailer lined up straight behind you. With full inflation, the trailer rolls better and so it can swing around easier. Putting the mower on backward might do the trick. I'd like to hear back what happens.

    Even my truck gets light in the rear if I load my CTL too far back on the trailer... very scary at highway speed!
  10. inHaliburton

    inHaliburton LawnSite Member
    from Picton
    Messages: 197

    I think you are right on the money, SiteSolutions. I'll be rearranging the load today until I get it right. Will let you know.

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