Trailer bouncing from side to side

W

wandererr

Adventurer
Narrow in boarded tent trailer frame with a stand up 6 foot box on top. Had to slow down and pulled over as it scared the crap out of me. Wondering if I need shocks? Setup is fairly light. I'm halfway to sequoia from la......
https://imgur.com/R6oYGSi
 
1

16crewmax

New member
Try to move some heavy stuff from the back of the trailer to the front. That should help fight the sway and keep her tracking straight


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1

16crewmax

New member
Just went through your build that trailer is definitely tail heavy, up the tongue weight and it should pull better. Pack any heavy gear, tools spare tires in your sleeping area


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W

wandererr

Adventurer
Not sure if that's it. It's not swaying from side to side. The trailer stays inline behind the jeep. It seems to be bouncing from left tire to right tire back to left tire (kinda like person standing in one spot and jumping from one leg to the other)
 
J

JPShooter

Adventurer
First off, it's hard to tell what you have there from a picture that far away and with bushes obscuring the bottom of the trailer.

I suspect that your problem is simply CG related. Center of gravity is what is at the core of a trailers towing behavior. Moving weight from the front to the rear or vice versa is simply adjusting the CG on one of three axis, which is the fore/aft or longitudinal axis. There are also the lateral and vertical axis to consider.

It appears to me that you have a very tall and narrow rig. If the vertical aspect of the CG is high on the vertical axis while the lateral axis is narrow (a narrow wheel base, i.e. short axle) then any bump or force applied to one side of the lateral axis will push that high riding center of mass (CG) laterally, which then runs into the resistance of the tire and or shock/spring which will then bounce it back again in the opposite direction. If the CG is high enough and the lateral axis short enough then you can develop an oscillation that feeds upon itself.

That's just a guess looking at the rig from the one picture from afar that you presented. A closer look from a side view and rear view would help to clear things up a bit.

P.S. Remember that the CG is a single point in space if you will. It sits in a position measurable on all three axis and is totally dependent on your rigs design and its load. CG not only effects the stability in towing that is demonstrated by the video linked in the post above, but a high CG effects how easily your rig will roll over on a slope or in a turn with G forces applied. In a static situation (no inertia from movement) a trailer will roll over only when the CG goes beyond the point directly over the pivot point (down hill tire).
 
Last edited:
rnArmy

rnArmy

Adventurer
If the suspension is too stiff it might "bounce" vs. the suspension doing what it is supposed to do (absorb bumps).
 
W

wandererr

Adventurer
I made it back.... I have shuffled weight all around and ended up with the following (for now) - all heavy items in the center right above the axle and two full cans of fuel up front on the tongue..... couldn't use my headlights as they lit up the sky but it got me all the way out to Yosemite and back to SoCal safely.

Things to do to address this:
- weigh the damn trailer
- estimate the amount of weight when complete
- double check the springs specs vs the weight
- check tongue weight on empty (kinda impractical maybe as the galley is not done)
- look into a wider axle and put the tires outside (wondering if I can use the same location for spring perches or if I want to move them outside a bit more)

I think that's all for now ;)
 
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