Another Death wobble experience...question...

[1NKOGNETO]

Hi guys..... First of all i want to ask...

My 2011 JK is setup with synergy shocks, PPm 4.5" springs, PPM drag link flip kit, Lower control arms, relocation bracket etc etc... All done to eliminate the dreaded death wobble from happening at all. Running 305/65/17 mud tyres on 17" 4.5" back spaced rims. Few guys have seen my rigs... Never had any issues with wobble.... ever so slight wobble sometimes when on a bend & hit a bumpy spot. Caster currently sitting at around 5degrees.

TODAY.... was ruined!! Decided to go for a drive to Kalgoorlie (6hr drive of pain ) to check on my house which i've done before BUT thought i might throw the original wheels on with factory tyres.... Quick test drive on the FWY JK drove like a dream, much less stress on the box taking off & fuel economy dramatically got better straight away... Might add i also check track bar etc & regressed while the front wheels were off. All good & tight still. So all geared up to leave, got about an hour & half out of town just past Perth hills & f#@K me dead, i got the fright of my life. coming around a bend hit a small bumpy patch & JK started violently wobbling at about 90Km/h didn't stop until i got to about 60km/h... Now from a good year of monitoring & reading i thought my steering what quite light & responsive so pulled over & checked tyre pressure... Damn ARB gauge had my tyres at about 42psi (which was blown up to 33psi cold before i left) glovebox tyre gauge was clearly more accurate. Dropped them to about 34psi (hot) Drove for another 20min & JK felt great!! much smoother on the road, steering medium heavy again & thought all was good. NO.... straight road, bumpy section doing 100km/h, damn thing tried to kill me again!!! not as violent as the first time but enough to make me pucker up & pull over & head back home. So all in all wasted a good 3.5hrs & should have been half way.

QUESTION????
What changes when running stock tyres after my setup? I know the lift is obviously an issue on stock tyres & looks a little silly. DOES the castor angle drop & could this be my issue?? I'm that pissed at the minute if anyone offered my the right amount of money id sell the damn thing without a second thought.
Has been a dream to drive apart from obvious needing regearing issues.

Not happy, now have to take the miss's car on the trek, not wanting to risk changing back to big muddies & possibly still playing up.....

THoughts???? Comments ?????

[mudyJK]

From what I understand the wobbles start at with the rear track bar, double check that?

[twin spin67]

I had a similar situation happen to me when i was on stock good year silent armour tyres on 2" mopar lift on my jku,went to 35's and no more death wobble,call me paranoid but i think it was my silent armours that caused it...Now on similar lift set up as yours Tonka Tuff with castor set at 6.5 deg and all good...

[ausjeeper]

Do you have the complete lift kit and upgraded front track bar?

[wranglertj]

i dont beleive the rear track bar will create or cause DW.

I would have a guess that it is your front panhard. Did you check it on the ground with someone turning the wheel and someone underneath checking both sides of this link?

I would also highly recommend (regardless if you have adj LCA) some LCA drop brackets as this will make a difference and certainly go a long way to prevent the onset of DW. I have had plenty of experiences with DW directly and with someone else and both time our DW was avoided with the LCA drop brackets even with the front panhard loose to prove a point.

If you have done the draglink flip i would assume you have a new draglink therefore new ball joints here and a new tie rod as well?

Are you running an aftermarket panhard and if so what type of bushes are they running? if nolethane they are rubbish regardless of brand and how strong, i do not know of any on the market that survive any great distance and had tried 2 nolathane bushes with my previous solid panhard and both flogged out and put the factory one back on with a relocation bracket which was much better.

It sucks big time but is solvable so i hear and feel your pain. I am now over a year DW free with no shimmy at all let alone DW

[1NKOGNETO]

no ausjeeper, no trackbar, just the track bar relocation bracket to bring her back to
factory angle.

Twin spin, yes we are now running a very similar setup, interesting your theory on the silent armours. Even handling wise i found them horrible, being thin & skinnier track width makes a big difference i think.

i also disagree with the rear track bar creating the problem, i could feel it as soon as the front end dropped into the bumps.

WranglerTJ - new drag link & tie rod that comes with link bar. no new balljoints, JK has only done 9000km & has really only been off road properly 2-3 times. Has not done any handwork although i'm not ruling the balljoints out. I know they can go early.

I may try the LCA drop brackets, but like i said the problem to date has NEVER happened running my 305's... Have done the Kal trip only 2 months ago with no hiccups BUT was on my 305's... Fuel usage was my only issue. Panhard was checked this morning & was still tight on 125lb torque. No movement what so ever.

Back to my main question. Would dropping tyre size take my castor angle down?

[Macca2801]

Wayne, to answer the question no! Changing wheel size (od/ width and offset have all changed) will not effect castor but width offset and OD will effect scrub radius and/or toe! Both of these are culprits in setting off a death wobble but to keep it there you still need something worn or loose.
Matt