Death Wobble - continued

[mrjeep4]

easiest way to cure wobbles ..         sell the jeep ..    get a civic

[Joel]

I'd rather find the *CAUSE* and fix that *and* the worn bushings etc. than replace bushings only to have them trashed again in short order because the *CAUSE* of the vibration that helped destroy them in the first place is not gone.

LOL.  So your going to run the jeep with worn out bushings/parts and hope to find the cause of your tire vibration?  Good luck with that.

[tubby]

easiest way to cure wobbles ..         sell the jeep ..    get a civic

AGREED

[The Machinist]

If there are two people I would ever ask for help on a my jeep it's Jay or Bill.  They both know more about suspensions and drivetrains than I will ever know and are both highly recommended.  Why would you come on here and try to dig up dirt on either of these guys???  I'm thinkin you better get used to that death wobble unless you can fix it yourself.  You may be burning your bridges with the two people that can help you with it.

[muffintop]

Tinkerer... consider changing your forum name to "Thinkerer" cause I think your overthinking this one.

1) In some way shape or form every vehicle has "the cause" especially if its been wheeled... focus your energy on "the fix"
2) If you have movement problems with CA's and/or track bar... fix it
3) If your tires feel square in the morning... up your air pressure

This is coming from a guy who should have death wobble but doesn't. Why? Got me a pretty good fix  

Good luck.

[Bnine]

I told you to get rid of those tires two years ago Pat. You ignored that recommendation citing you couldn't afford to change them.

I showed you how to reinforce your frontend to the point that it would handle you shtty tires and you ignored that, citing you can't afford the upgrade.

I hold Jay in the highest regards. That doesn't mean he has the experience with dw that I do.

For instance, most techs don't realize that the durometer of the stock bushings is barely hard enough to tolate the forces from stock tires.

Even a good condition stock bushing can allow for death wobble when subjected to the forces of a larger then stock tire. Specially a poor condition tire.
This is something most techs don't realize. Only after you've fixed this issue a few hundred times do you start to understand all the subtle intricicies involved in keeping a tj front end under control.

At least you accomplished one thing Pat.

My DW diagnostics are 50 bucks now.

That way the next time some leaves my shop and ignores everything I've told them, at least MY time isn't a total waste.

[Joel]

Jay also comes pretty highly recommended on the board for the past few years, but perhaps I'm wrong to believe him? Someone enlighten me on that one, please. PM me the dirt if you don't want to diss him in the open forum.

Pat, don't start crap.  I've got no issues with jay, I've only ever heard good things about his work and his fab skills.

What i do know is Billy's IS the expert in diagnosing DW issues.   I can't even remember how many people he's helped on this site when it comes to death wobble.

[JackstandJohnny]

Ok, here's the latest... Jay looked at the Jeep, drove it, went over it up and down, wiggled it (ok, I wiggled, he looked), put it in the air on the hoist, on jack stands (drive shaft binding at full droop), ran it on the stands, balanced the front tires (not knowing there was CounterAct balancing beads in the tires) and came to the "soft" conclusion that it's the tires.  (There was a lot less vibration etc. on the way home, but then it does come and go like Calgary weather.)

So I guess I'm not doing arms right away, he recommended that I should put a t-case drop in (Like it isn't low enough already, there goes any clearance gained from the tires and pucks) and get the new tires in my garage swapped on and see if that makes it go away. If so - great... and find another brand of tire to buy in the future, if not - we dig way deeper.

have you swapped a new set of tires on yet?  or a new trackbar?

you've answered the question, and had many others answer it; why debate which is right? 

  why not cancel out their deductions by testing?  i'm too busy to help this weekend, but why not swap in a set of known, good tires, and put a new trackbar? stop diggin and start wrenchin

[Elsifer]

Man, entertaining read, but I'll only wade in half way, out of politeness to all involved.

A front suspension has X number of parts, of which, roughly 4/5 of X are designed to move (a little or a lot, doesn't matter).

Death wobble is always a collection of things that are not supposed to happen. Sure, one "fix" may cure it, for a while, but it will always return, and then it will be more parts because the original fix masked the other issues.


As for Bill and Jay; between the two of them, there is more mechanical know-how than most car dealerships have. Jay works on my Dodge truck, because he was highly recommended by at least 5 people, both on this forum, and off. Done. He wrenches on my daily driver/work commuter/heep hauler/money-maker. Why? Because he knows wtf he is doing, so I trust him with it!
Bill is the DW expert, because he is good at it! He looks at it from the 4x4 enthusiasts viewpoint, whereas a mechanic may not have that particular viewpoint experience. Big tires + large offset + just-good-enough-engineering-of-stock-components.
In this case, both have that viewpoint, both have the equipment to diagnose it, and when things are spinning, and moving 70+km/hr down the road, a visual inspection may not catch the issue!! We are talking about some things that have deviances in the thousandths of an inch!

Geometry is that, geometric. You mentioned it was in an accident between Bills viewing and Jays viewing. You quite likely have 1/3 of X out of whack/tolerance/worn/bad/no-good/etc. DW is an evil bastard, I agree, and sometimes it takes a lot of parts to cure it.

Anyways, nuff said.
Pat, not sure why you've gone this far pointing fingers, and speaking ill; but these are two well respected and knowledgeable people here. Both of which I respect and trust.
Need I say more?

[BlackYJ]

Honestly Pat, you will probably never find the exact source of the vibration but you want your front end stiff enough so that the natural frequency of your front end and the 2nd and 3rd harmonics of that frequency are high enough so that inputs from driving do not excite your front end.  It takes very little energy to excite a system if that energy is at the right frequency, especially if that frequency is very low.  Stiffness is the best form to dampen vibration

[muffintop]

The following backs up what Bnine is saying about rubber durometer and what BlackYJ is saying about stiffness being a good "control" fro DW.

My TJ...

1) Currie lift, steering and unit bearings (3 wheelin trips old)
2) 35" X-terrains on 17" AEV beadlocks (never seen a balancing weight)
3) Just finished wheeling in sticky mud (big chunks of mud randomly stuck to my rims)
4) Steering stabilizer had actually come off while wheelin (not hooked up at all)
5) I drove home from MaClean Creek at about 110 KPH... not a hint of deathwobble or any substantial vibration. Hmmm? Lots of "cause" there... why no death wobble? It was controlled... all without the help of balanced tires & rims or a steering stabilizer.

BTW... did I mention that I have a man crush on Johnny Joints? Check this out... pretty impressive:

http://www.jpmagazine.com/projectbuild/154_0906_project_2001_jeep_wrangler_tj_revisited/index.html

Here is the Coles notes if anyone is too lazy to read for themselves 

"Way back in November of 2002, Cappa installed a 4-inch Currie Enterprises lift kit and 35-inch tires on Red. Well, that lift kit worked fine for five years and roughly 80,000 miles. The Johnny Joints were a-knocking, so we took it down to Currie Enterprises for a 100,000 mile checkup. Currie rebuilt what needed rebuilding and replaced worn out parts with the new-design parts, but basically the 4-inch lift kit we put on the Jeep back in '02 still clears our 35-inch tires, and still works well off-road for what we want it to do"

"With the clunking and noises we were hearing coming from under the Jeep, we expected our old Johnny Joint parts (right) to look way worse than what they did. Out of eight joints, only four had bushings that were beyond saving but we went with all new bushings to make sure. The metal beans were simply cleaned up and reused"

[Immortal]

On a lighter note...

excite your front end.  It takes very little energy to excite .....  Stiffness is the best

Scott's mind is in the gutter again...

[frenchy]