Sway and oscillation

[grizzjeeper]

2016 Power wagon, 77k miles. At about 60 thousand I noticed the side to side sway when trailering was getting worse, ironically the heavier the trailer the better the sway got but I digress.

At about 65k I started noticing the side to side sway unladen, felt like the shocks were not controlling the bounce. So I replaced them with Rancho 9000 rs. I figured having the adjustability would be nice. Well i now have them cranked up to full firm and I no difference... so.. Brought it to the dealer, i got the typical we could not replicate the problem must be your tires... and everything is tight underneath nothing wrong..

So, 1. either the new shocks are not up to the task (Seems unlikely considering the price point and adjustability) or 2 something else is the culprit. I have noticed my springs have sagged considerably since when it was new. You dont really notice until its sitting next to a new one.. could worn out springs cause this?

Thoughts? Thanks.

[machete-lc]

My 2015 sounds like it is replicating your trucks issues (still have the stock shocks). I just got off the phone with Chris at Thuren Fabrication and he recommended track bars front and rear as well as shocks and front springs (I do not want to lift my truck and need the stiffer rear springs as I tow once in a while and have a topper and a Decked system that add weight to the bed of my truck). I don't have the $$ for the King 2.5's he recommended at this time (around $2300.00) so he recommended just the track bars for now. I am still in sticker shock on the price of those shocks (pun kinda intended, LOL). I ordered the track bars and I am hoping they improve my ride at least until I can upgrade and get better shocks. Chris was super helpful, here is his contact info:
Chris Willett
thuren.sales@gmail.com
541-508-9190

[TankerZak]

Does it feel like the rear end is wagging? Because that is the rear trackbar. Or your tire sidewalls are too squishy. Usually the trackbar. Also... if you are towing airbags can help firm it up. Honestly the rear trackbar design is boarderline criminal and shoulda been replaced before it left the dealer lot...

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[KevinABQ]

I have King 2.5s and it is more unstable at low pressure and high speed than stock. Running at 25 psi in toyo 37 MTs at 50+ mph stability control kicked in multiple times in a few miles until I slowed down. It's fine at 45-50 psi. Not saying this is what' going on, but maybe?

[machete-lc]

Hey Keven in ABQ,

LOL, if you are in ABQ proper, I am 30 miles south of you and would love to chat about your suspension sometime. I actually added pressure to my tires based on your post and it really improved the ride. Still has a little float but I am installing the Thuren Trackbars likely this next coming week.

Grizzjeeper I am not sure what pressures you are running but with my added weight and moving from BFGs to Nittos I needed 15 PSI more pressure to keep the same ride. Hopefully this helps

MLC

[KevinABQ]

I'm in NW Albuquerque, near RR. Sure.

[gen1runner]

I had off the shelf fox 2.0s and i would get terrible sway not even towing or hauling just everyday driving. I got Kings all around and a thuren rear trackbar. Gone, feels like a totally different truck now

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[machete-lc]

Update: Installed the front and rear Thuren trackbars and I have to say my truck drives better than it ever has. Drove today in 40 mph crosswind gusts and it handled great considering. Well worth the cost!

[PJElko]

I have a 2018 in stock condition, at least as far as the suspension and tires are concerned. Running tire pressure at 65 psi. I have a camper shell and carry some tools all the time. I first noticed, what I call the "Death Sway" at 28,000 miles. I had suitcases, a cooler and some camping gear in the back, so not really much of a load. Going down the interstate at around 70 to 75 MPH, the sway became so severe that traction control kicked in to stop it. I now have about 32,500 miles on my PW. Although I cannot replicate it all of the time, when it does happen I am usually travelling at 70 MPH or faster with some load (but definitely not a big load). It does it whether I am pulling a trailer or not (Boy Scout trailer weighing about 3,500 lbs. total and evenly loaded. Traction control usually kicks in to stop it. Basically, once the sway starts, it does not want to stop. I'll look at some recommendations found here and see if I find any glaring issues to report back.

[PWJouster]

this is what we have going on as well pretty much.

glad to know it happens on stock worn trucks or full aftermarket worn trucks.
unless we address ball joints, trackbar bushings, radius arm bushings, shock bushings....all the bushings, we wont really know what is causing it..
its just the nature of heavy rigs on solid axles with springs and inward shock mounts.


i have the same issue loaded or unloaded at speed on the highway.
if the sway starts, more speed makes it worse, and it wont stop until i slow down enough to level out...
I think its a factor of Crosswinds as well.

[TankerZak]

Is it the back end wiggling? Do you have Thuren rear trackbar yet? That solved most wiggle for me...

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[PWJouster]

can confirm the thuren front and rear trackbar setups do not solve this issue.

i have both.

[machete-lc]

What is your tire pressure PMJouster? I didn't think it was a possibility but after KevinABQ mentioned tire pressure I went from 35 to 50 PSI and it made a big difference. Hopefully it is something as simple as this, otherwise that sounds dangerous! Stay safe!

[KevinABQ]

Yeah, I was amazed at how much it changed. With stock it was no problem at 30-35 and I think with the 37 toyos on otherwise stock it was fine at 30-35. But either the wheels or the the suspension made it highly inadvisable to run at 30-35 past about 45 mph on pavement.

My bet is the suspension, but it does soak up the bumps really effectively at correct pressure.

[PWJouster]

i would be really surprised... im typically 40 front 32 rear cold.

so 4 large passengers and i actually need to crank that over 50 psi lol

while i dont doubt it has an effect, i didnt think this was the real issue...

i really need to get on that chalk test.