1500 Rear Stepping right over speed bumps

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Black1500Ram

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Hi guys,

My truck used to step out to the right going over bumps at higher speeds (40/50mph), rebuilt the suspension at ~ 100k planning to keep the truck for another 100k+ and it went away… now it’s doing it again over speed bumps at 10-15mph. Front is fine, rear noticeably steps right.

Entire suspension has been replaced <30k on it: 5100’s, Freedom off-road rear control arms and panhard bar, hellwig rear sway on middle setting, moog everything else: Bushings, front control arms, ball joints, sway end links, wheel bearings

Could the shocks have gone bad this soon?
Could this be the difference in tire size and rating?

Tires are new (<5k mi) Falken AT3w P285/70/17 run at 40psi all around. About to do the chalk test to verify even wear / appropriate pressure.

Previously had 20” 275/60/20 LT rated tires

Any thoughts would be appreciated.

P.s: truck is ‘lifted’ 2.1” front, 1” spring spacer rear, has 3.92 LSD rear and alignment was done <5k miles ago.
 
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crash68

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yeah, what he said
Have a full four wheel alignment done, it's possible the rear axle thrust angle is off
 
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Black1500Ram

Black1500Ram

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Last sentence, alignment was done within the last 5k thrust angle was 0.13°, in spec.

I don’t have a drop bracket for the panhardbar, I lengthened it fractionally when the rear spacers were put in to keep the axle centered. It's ~1° increase in the angle of the bar, away from the already innapropriate stock geometry (bar not parrallel at ride height); didn't think it would be that big of a deal, but an angled panhard bar at ride height will cause bumpsteer...

I may order a drop bracket just for giggles.
 
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Mister Luck

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:mexsmoke:Hi guys,

My truck used to step out to the right going over bumps at higher speeds (40/50mph), rebuilt the suspension at ~ 100k planning to keep the truck for another 100k+ and it went away… now it’s doing it again over speed bumps at 10-15mph. Front is fine, rear noticeably steps right.

Entire suspension has been replaced <30k on it: 5100’s, Freedom off-road rear control arms and track bar, hellweig rear sway on middle setting, moog everything else: Bushings, front control arms, ball joints, sway end links, wheel bearings

Could the shocks have gone bad this soon?
Could this be the difference in tire size and rating?

Tires are new (<5k mi) Falken AT3w P285/70/17 run at 40psi all around. About to do the chalk test to verify even wear / appropriate pressure.

Previously had 20” 275/60/20 LT rated tires

Any thoughts would be appreciated.

P.s: truck is ‘lifted’ 2.1” front, 1” spring spacer rear, has 3.92 LSD rear and alignment was done <5k miles ago.
Do you travel with any load in the bed ?
 
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Black1500Ram

Black1500Ram

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I keep my jack and a pair of 6ton jack stands as well as some small power tools probably 150lbs…

It also did it when I was fully loaded the other day with fire wood.
 
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olyelr

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Last sentence, alignment was done within the last 5k thrust angle was 0.13°, in spec.

I don’t have a drop bracket for the panhardbar, I lengthened it fractionally when the rear spacers were put in to keep the axle centered. It's ~1° increase in the angle of the bar, away from the already innapropriate stock geometry (bar not parrallel at ride height); didn't think it would be that big of a deal, but an angled panhard bar at ride height will cause bumpsteer...

I may order a drop bracket just for giggles.
Haaaa. Uhhhh, no. You wont get any bump steer from the rear track bar. Thats a term for the front of a solid axle truck…when the track bar and drag link are not very close to the same alignment/length.

However, when your rear suspension cycles, the truck actually moves left/right over the rear axle…is that the feeling you are referring to maybe? A level track bar at ride height will help keep this to a minimum….but it will still always occur.
 

olyelr

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Ive never noticed the side to side feeling with my half ton. But with my power wagon, its definitely noticeable. Its even worse on the power wagon, because it has apposing track bars. As the front axle cycles down it moves to the drivers side of the truck (roughly several inches). As the rear axle cycles down it moves to the passenger side of the truck. So, say you are speeding down the road and come across a quick dip in the road and it makes the suspension compress/unload quickly, you can literally feel the truck basically twist over the axles.
 

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I keep my jack and a pair of 6ton jack stands as well as some small power tools probably 150lbs…

It also did it when I was fully loaded the other day with wire wood.
Was it loaded when you had the alignment preformed .?
 
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Black1500Ram

Black1500Ram

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Haaaa. Uhhhh, no. You wont get any bump steer from the rear track bar. Thats a term for the front of a solid axle truck…when the track bar and drag link are not very close to the same alignment/length.

However, when your rear suspension cycles, the truck actually moves left/right over the rear axle…is that the feeling you are referring to maybe? A level track bar at ride height will help keep this to a minimum….but it will still always occur.
Yeah that's what I mean, the lateral movement of the rear axle caused by the suspension geometry

What the heck is wire wood LOL

Edit: i bet you meant fire wood haaaa. I even googled it first lmao
Yes I meant fire wood lol... heavy eucalyptus.. floatyAF with these tires but wasn't going far.
IMG_0669.jpg

Was it loaded when you had the alignment preformed .?
It was loaded with jack and tools
 

olyelr

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Yeah that's what I mean, the lateral movement of the rear axle caused by the suspension geometry


Yes I meant fire wood lol... heavy eucalyptus.. floatyAF with these tires but wasn't going far.
View attachment 540962


It was loaded with jack and tools
I towed our travel trailer for 4 years on 35” at3w’s. Solid as could be for me. Load range e though and usually aired them back up to max.
 
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Black1500Ram

Black1500Ram

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I towed our travel trailer for 4 years on 35” at3w’s. Solid as could be for me. Load range e though and usually aired them back up to max.
I have the P rated ones. If they were LT's it wouldn't be a thought.
I got these wheels and tires looking for ultimate lightweight while still being AT - 70lbs mounted weight per corner; not going to get much lighter than that for 17's on 33 AT's

I very rarely tow or haul anymore so I deal with it for the ~ 3/4 times a year that I do.
 
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Kenduro

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Ive never noticed the side to side feeling with my half ton. But with my power wagon, its definitely noticeable. Its even worse on the power wagon, because it has apposing track bars. As the front axle cycles down it moves to the drivers side of the truck (roughly several inches). As the rear axle cycles down it moves to the passenger side of the truck. So, say you are speeding down the road and come across a quick dip in the road and it makes the suspension compress/unload quickly, you can literally feel the truck basically twist over the axles.
If you want/need to cross speed bumps at 50 mph, you need to replace panard with a Z-bar. At those speeds the inertia has too great of an effect. This will also increase the life of all your rubber.
 

olyelr

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If you want/need to cross speed bumps at 50 mph, you need to replace panard with a Z-bar. At those speeds the inertia has too great of an effect. This will also increase the life of all your rubber.
Im not saying i hit speed bumps at 50 lol…im talking normal “dips” in rural back roads that cause the suspension to cycle up and down while traveling at the 55mph speed limit.
 

ram1500rsm

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Check the bushings on the trackbar. Check the bushings in your rear control arms. Make sure everything is torqued down to specs.
 
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