gladiator jump and pull with bumps at low speeds

[jmdusza01]

Greetings group. Have a 2021 Gladiator overland with the mopar 2.5 inch lift kit installed by dealer in October with 285 70 r17 tires on Quadratec aftermarket rims. Recently added Fox upgraded steering stabilizer and steersmarts Yeti adjustable front trac bar. Still have wander. Had a comprehensive alignment performed, adjusted torque on all suspension parts and front ball joints, and lowered tire pressure to 32. Vehicle recently is wobbling over road with bumps a pulls at low speeds. WTF. Am trying to schedule followup service with dealership that has done all work. Any input on possible issue (s)?

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[NewGladdyOWNR]

What is your caster specs after alignment? To my knowledge the mopar lift kit isn’t a complete lift kit as you really need adjustable front UCA’s at the minimum to get proper pinion angle and caster.

 

[darkhorse13]

Definitely check caster and make sure you're at least at +5.5. I've been running +6.5 with 37's for the last 1.5 years with zero issues. I personally like Synergy control arms with the double adjuster sleeve so that you don't have to drop a side of the arm to correct caster.

Also, recheck the track bar bolts. This is always a source of steering issues if loose. Finally, if you still have the alloy steering box maybe see about the updated version or get a Synergy Sector Shaft brace... this one upgrade improved my front setup beyond expectations.

I know it sounds like bad advice spending money on parts that aren't broke, but if you want to future proof your steering and rule out any weakness due to OEM parts, I'd highly recommend upgrading your tie rod and drag link as well. (at a minimum the tie rod) You've already done the right thing with replacing the track bar The OEM tie rod can only be described as "flimsy" when you take it off to replace it with a Synergy or Yeti (both are great, I just started with Synergy and all my components followed suit)

 

[ShadowsPapa]

What's the backset on those wheels compared to stock? Changing wheels often results in a change to the scrub radius which results in squirm and instability if it reaches 0. Too positive is also an issue.

If you move the centerline of the tires/wheels outward you increase (make more positive) the scrub radius. Tires sticking out like with wheels or spacers may look tough, mean, manly, but it's a negative impact on stability. Any bump has more leverage over things, you get tramlining, etc.

As scrub radius increased, there is less feedback at the wheel due to the fact the tire is scrubbing and doesn't have as much grip. The greater the positive scrub radius, the less effort to turn the wheel and the less feed back to the steering wheel.

I'm not saying that's the definitive cause here but any time I see wheels have been changed, or spacers used, or anything else that changes the scrub radius or moves the centerline of the tire compared to SAI, and then people talk about steering issues - well........

 

[jmdusza01]

What's the backset on those wheels compared to stock? Changing wheels often results in a change to the scrub radius which results in squirm and instability if it reaches 0. Too positive is also an issue.

If you move the centerline of the tires/wheels outward you increase (make more positive) the scrub radius. Tires sticking out like with wheels or spacers may look tough, mean, manly, but it's a negative impact on stability. Any bump has more leverage over things, you get tramlining, etc.

As scrub radius increased, there is less feedback at the wheel due to the fact the tire is scrubbing and doesn't have as much grip. The greater the positive scrub radius, the less effort to turn the wheel and the less feed back to the steering wheel.

I'm not saying that's the definitive cause here but any time I see wheels have been changed, or spacers used, or anything else that changes the scrub radius or moves the centerline of the tire compared to SAI, and then people talk about steering issues - well........

Not much. Just

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