Rear-end Sway/Right Pull after new Wheels and Tires

[aaronedmonton]

Disclaimer: Tried the search function, it sucks.

Now on to my current situation:
Truck:
2021 Ram 2500 Tradesman 4x4 6.4L Hemi - Otherwise stock besides below

I recently purchased 18x9 American Racing wheels with some LT35x12.50R18 Hercules AT-X Venture tires, as well as 2in front spacer lift.

I have been driving it recently and noticed the back end very slightly pulling to the right (with the pitch of the road.) The front seems to stay straight, with the back end coming out to the right a slight bit. It is pretty slight in most areas. I have an intense human gyrometer so I feel it when it feels like it's crabwalking.

Now this happens mostly with the pitch of the road and only the rear end "feels" like it's moving. I do have to hold the steering wheel slightly to the left to counteract the pull. Tire pressure is at 65 all around on these A/T tires. Might be slightly high. It doesn't seem to crabwalk with a trailer.

I took it back to the shop to ensure everything is setup correctly. They said it all looks good, and that RAMs have some issues with heavier tires. Rear tires were swapped from left to right to ensure good tires still. I know from experience with my dad's Ram 2500 that had Toyo M/Ts, it would pull right but the whole truck, not just the rear (again, subjective feeling.) With my dad's truck, we installed that upper steering stabilizer and it corrected the right pull.

When I very gently flick the steering either direction, the back end sways quite a bit. Didn't notice this with stock tires and wheels. Why does it sway so much?! Could be the coil springs? There is no extra movement vertically, only horizontally.

Some questions so far to start:

Do I need an Upper Steering Stabilizer? Doesn't seem to be an issue with the front and there shouldn't be much adjustment in the rear, if any.
Do I need an aftermarket track bar? (Left and right sides look identical, not really moved towards one side after level)
Do I need to lower tire pressure to 50 unloaded?
Do I need a stiffer/better rear sway bar to handle the extra weight in wheels and tires?

Just looking for a direction to head in if I want to correct this.

 

[Crusty old shellback]

I put BFG 35s on my Power Wagon and had the truck aligned to Thuren specs. No issues at all.
If it didnt do it before the tire/wheels/spacers, then one of them is out of whack.
Check your tires and see how much balance weight they put on. If it's a lot, or in several places, then the tire is bad and will never balance.

 

[jetrinka]

Lower those tire pressures - especially the rears. I've got my Hemi set to 50 front and 45 rear unloaded and the outer edges of the rear tire treads are still just barely not contacting the road. I may lower them more. E-rated 35's don't need as much air in them to accomplish the same load task as the smaller tires do.

 

[GPurcell01]

Had this issue with my old 1500 with the coil sprung rear. Welcome to the world of 5 links. The rear end of mine would always kick to the right over big bumps too.

https://www.thurenfabrication.com/c...ar-kit-for-2014-up-dodge-ram-2500-power-wagon

 

[Crusty old shellback]

Lower those tire pressures - especially the rears. I've got my Hemi set to 50 front and 45 rear unloaded and the outer edges of the rear tire treads are still just barely not contacting the road. I may lower them more. E-rated 35's don't need as much air in them to accomplish the same load task as the smaller tires do.

I'm running 45/37 and it seems to be about right.

 

[jetrinka]

I'm running 45/37 and it seems to be about right.

Did you notice fuel economy drop off in any significant amount at those pressures?

 

[jetrinka]

Had this issue with my old 1500 with the coil sprung rear. Welcome to the world of 5 links. The rear end of mine would always kick to the right over big bumps too.

https://www.thurenfabrication.com/c...ar-kit-for-2014-up-dodge-ram-2500-power-wagon

Yes due to the axle able to physically walk sideways under the truck as the frame moves up and down from its neutral position. Front axles do the same thing but the rear seems to manifest more due to the angle of the track bar in relation to the bottom of the frame. Too high of tire pressure just makes this worse as the tire is allowed to jump/skid (in small terms) across the pavement instead of gripping.

 

[Crusty old shellback]

Did you notice fuel economy drop off in any significant amount at those pressures?

My MPG hasn't really changed. I put the larger tires on at 200 mile sand used ALFAOBD to change the tire size/TPMS warning.

I've run a few different pressures.
50/50, 45/40, 45/37, 40/35.
45/37 seems to be about right for tire wear.

Also I'm a little heavy footed so my MPG is lower than everyone else it seems.

 

[jetrinka]

My MPG hasn't really changed. I put the larger tires on at 200 mile sand used ALFAOBD to change the tire size/TPMS warning.

I've run a few different pressures.
50/50, 45/40, 45/37, 40/35.
45/37 seems to be about right for tire wear.

Also I'm a little heavy footed so my MPG is lower than everyone else it seems.

haha I supposed "Hemi" and "fuel economy" never belong in the same sentence anyway... Sometimes I find it comical that they even have MDS or Eco mode seeing as it does absolutely nothing...

 

[Crusty old shellback]

I did hit 16 MPG once on the freeway. But it was mostly 55 mph driving.

 

[aaronedmonton]

I’ll try some lower pressure and see if that helps. I may want to add a steering stabilizer at some point to control the front end a bit better. Maybe that would help with the pull. I have researched some heavy duty rear sway bars as well that may be an option down the road.

 

[H3LZSN1P3R]

I’ll try some lower pressure and see if that helps. I may want to add a steering stabilizer at some point to control the front end a bit better. Maybe that would help with the pull. I have researched some heavy duty rear sway bars as well that may be an option down the road.

Steering stabilizers only prevent the steering wheel from ripping out of your hand when hitting bumps it does not fix any steering issues

 

[aaronedmonton]

Steering stabilizers only prevent the steering wheel from ripping out of your hand when hitting bumps it does not fix any steering issues

The Carli high mount stabilizer can be set to give push depending on which way it’s pulling. We did that on my dads Ram 2500 Cummins and it corrected the right pull

 

[H3LZSN1P3R]

The Carli high mount stabilizer can be set to give push depending on which way it’s pulling. We did that on my dads Ram 2500 Cummins and it corrected the right pull

It does not correct anything it hides it proper alignment will correct a pull unless there are brakes draging or a low tire

 

[jetrinka]

It does not correct anything it hides it proper alignment will correct a pull unless there are brakes draging or a low tire

Or road crown. And in that case a stabilizer will make the car pull twice as hard the other way when you encounter roads crowned to the left.

 

[H3LZSN1P3R]

Or road crown. And in that case a stabilizer will make the car pull twice as hard the other way when you encounter roads crowned to the left.

Does the states not have proper roads? Here in Canada any roads built/ rebuilt has a the same crown, but funny enough every alignment machine i have ever used lists american or canadian specs which basically had different caster settings to accommodate road crown

 

[jetrinka]

Weird never seen different caster specs.

And our roads are all mostly crowned for runoff correctly. Exceptions being the left lanes on the freeways being crowned/worn so it creates a left drift instead of right. Some other roads seem very flat with no crown so it would be irritating IMO to have to fight a stabilizer the other way.

Like you said it’s a really poor bandaid

 

[jetrinka]

If one really wants to use alignment to battle crown have the shop dial a little cross caster in with the drivers being about .5 degrees less than the passenger. Truck light lean (supposedly according to Thuren) a bit but it should compensate some for the crown.

 

[H3LZSN1P3R]

Weird never seen different caster specs.

And our roads are all mostly crowned for runoff correctly. Exceptions being the left lanes on the freeways being crowned/worn so it creates a left drift instead of right. Some other roads seem very flat with no crown so it would be irritating IMO to have to fight a stabilizer the other way.

Like you said it’s a really poor bandaid

We have a pretty standard 2° run off for all roads which is nice but you do get a good left pull when you go to pass someone on a 2 lane road lol

 

[aaronedmonton]

Update:

Lowered tire pressure to 55 in front and 50 in rear. Wow, what a better ride I’ve been missing. Not just the up and down movement of the suspension but the truck doesn’t jump around over rough roads anymore and feel like I’m going to wreck lol. It rides like it’s on rails for the most part. A little bit of the rear end feeling still swaying but I have a few more PSI to release.