Forum Discussion

Yosemite_Sam1's avatar
Oct 28, 2019

Buckling bronco!

Nothing really serious nor worrisome.

I upgraded to two axle RV from just one. The buckling is a little more noticeable this time.

Got a heavy duty WDH and sway bar and setting is bubble-in-the-middle level.

Is there still something wrong with my set up or is this the natural characteristics of double-axle TT? If it is, it must be a killer to the tires and the good 'ol mpg, lol.

27 Replies

  • WVcampground wrote:
    Snip...

    Scale numbers? I agree his setup is most likely the culprit but I have yet to see a manufacturer of a WDH tell you to go to scales to set one up. I also have yet to see an RV dealer take a rig to a CAT scale to set one up. It's done by measurements from a level surface, it's not a guess.


    There are several things wrong with this statement.
    First, the manufacturer has no idea what kind of trailer or truck his equipment is going to be used on and so gives generic information on how to set one up. This is designed to get you into the ball park and may often be ok for some users but not all.

    Second, The dealer is not going to spend the time necessary to properly set up the hitch because it takes too much time and time is money. Rarely do the generic setups get the WD exactly right for an optimal towing experience.

    Third, most dealers techs just go by the book and set the hitch up according to the directions or just "how they always do it". This, in most cases, is not the best set up for that particular combination of truck and trailer.

    Forth, The dealer cannot know exactly how the owner is going to load the trailer so cannot get the WD set properly. The only way to do that is scale the trailer.

    Which brings us to to the last part of your statement which is not accurate.
    Setting up the WD by using fender measurements is only a guess as to what is the best WD possible. Variations in spring movement and truck measurements make this method good for a "ball park" setting but to get it correct the only way is to measure the axle weights on a scale.

    This is very easy to do now that scales are all over the place in truck stops, waste disposal yards, landscaping yards, etc. I used to weigh every year on my way South for the winter to make sure I was within my trucks ratings and to check how well my WD was holding up. That can change with wearing of hitch parts in certain hitches

    Bottom line is that I would not trust the dealer to get the WD setup correct and would suggest to anyone that they should get scale weights if they are serious in setting up their trailer and truck to tow as well as it possibly can.
    Barney
  • BarneyS wrote:
    Sam,
    The level of the TT has very little to do with how much the trailer will porpoise or with how well the WD works. Although you want to tow with the trailer in a level attitude for clearance issues and sway issues, the bouncing you are describing is probably due to an improperly set up WD hitch.

    Take a long look at this thread for some direction in setting one up. Also the advice to get your rig weighed is right on. Without scale numbers everything is just a guess.
    Barney


    Wow, this is a rich material for information. I'm learning a lot already,

    Thanks!
  • BarneyS wrote:
    Sam,
    The level of the TT has very little to do with how much the trailer will porpoise or with how well the WD works. Although you want to tow with the trailer in a level attitude for clearance issues and sway issues, the bouncing you are describing is probably due to an improperly set up WD hitch.

    Take a long look at this thread for some direction in setting one up. Also the advice to get your rig weighed is right on. Without scale numbers everything is just a guess.
    Barney


    Scale numbers? I agree his setup is most likely the culprit but I have yet to see a manufacturer of a WDH tell you to go to scales to set one up. I also have yet to see an RV dealer take a rig to a CAT scale to set one up. It's done by measurements from a level surface, it's not a guess.
  • Sam,
    The level of the TT has very little to do with how much the trailer will porpoise or with how well the WD works. Although you want to tow with the trailer in a level attitude for clearance issues and sway issues, the bouncing you are describing is probably due to an improperly set up WD hitch.

    Take a long look at this thread for some direction in setting one up. Also the advice to get your rig weighed is right on. Without scale numbers everything is just a guess.
    Barney
  • JIMNLIN wrote:
    Tandem axle trailers the same size of a single axle trailer will be a much smoother ride when the numbers are dialed in. Made a living pulling both (enclosed trailers). Never again...



    Actually that's my expectations too, that's why I'm surprised and this post.

    In fact, tandem axle is easier to set up and it's almost naturally (or defaults) to being bubble-in-the-middle level on a relatively flat campsite and roads.
  • Tandem axle trailers the same size of a single axle trailer will be a much smoother ride when the numbers are dialed in. Made a living pulling both (enclosed trailers). Never again.

    Without knowing any of your tow vehicles GAWRs and GVWR/vehicle type and not showing any actual scaled axle loads from the tow vehicle and trailer axle loads.... all we can do is guess.
    Guessing leads to speculations and far out there opinions that won't help you with your issues.

    Get some scaled weight numbers/measurements before and after. Then work with those numbers.