Odd Death Wobble Issue

C

CJ007

New member
I have an 07 JKUR with 37" KO2's on stock JL Rubicon wheels on it...I can run 80mph down the interstate no problem. When I put on my 39" Krawlers on KMC bead lock wheels, I can't get much past 35mph and it goes bezerk.

I've been pondering something loose, caster, toe-in/out, something this, something that, etc. These wheels are new-to-me and look fantastic. They were still mounted on the Gladiator the guy I bought them off of had, and have only minor rash on the rings.

I did not balance these, I put 14oz of beads in each and assumed it would get me awful close and I'd adjust from there. Did I underthink that part of it?

I'm struggling to think it's suspension related given the ZERO issues with 37's?

Thoughts?
 
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Are you talking Reds? Why would you ever need to go over 35mph on the street on a set of Krawlers? And why would you drive these on the street other than very short distances in the first place?
 
OK, I appreciate the advice, I will get the beads out of there and take him to a shop and we’ll see how close we can get with them. And by the way, these are blue DOT 39s.

I certainly don’t need to go 80 miles an hour in them, but it would be nice to be able to roll down the highway 55 to 65
 
CJ007 said:
OK, I appreciate the advice, I will get the beads out of there and take him to a shop and we’ll see how close we can get with them. And by the way, these are blue DOT 39s.

I certainly don’t need to go 80 miles an hour in them, but it would be nice to be able to roll down the highway 55 to 65
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These tires are a badass design, but I wonder if such large spaced out lugs may contribute to them being difficult to balance. I know of a guy here that runs a set of blues and they are balanced - I've driven it too fast so it can definitely be done
 
GP NOIR said:
Just know that tire balance will not fix or cause DWs. You’ll still need to go through the steering to find what’s worn.
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Well that leads me back to the beginning…. Why are my 37s okay at virtually any speed and my 39s only good to 35mph?

Something is different. Something matters. Is it as simple as me being on the fringe with my 37s and then all of a sudden out of balance 39s exacerbate every weakness and death wobble? Seems like a stretch given the disparity of speeds.

I’m going to get it aligned professionally before getting these tires balanced and put back on. I’m missing something.
 
CJ007 said:
Well that leads me back to the beginning…. Why are my 37s okay at virtually any speed and my 39s only good to 35mph?

Something is different. Something matters. Is it as simple as me being on the fringe with my 37s and then all of a sudden out of balance 39s exacerbate every weakness and death wobble? Seems like a stretch given the disparity of speeds.

I’m going to get it aligned professionally before getting these tires balanced and put back on. I’m missing something.
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You can do the alignment yourself - I'd get the wheels balanced first & go from there.

www.wayalife.com

Basic Do-it-Yourself Jeep JK Wrangler Front End Alignment

If you've just installed a brand new lift on your Jeep JK Wrangler and are wanting to get it aligned, there are a few things you should know before you take it to a shop and pay to have it done. First off, you should know that thanks to the new steering design on the Jeep JK Wrangler, very...
www.wayalife.com www.wayalife.com
 
Ddays said:
You can do the alignment yourself - I'd get the wheels balanced first & go from there.

www.wayalife.com

Basic Do-it-Yourself Jeep JK Wrangler Front End Alignment

If you've just installed a brand new lift on your Jeep JK Wrangler and are wanting to get it aligned, there are a few things you should know before you take it to a shop and pay to have it done. First off, you should know that thanks to the new steering design on the Jeep JK Wrangler, very...
www.wayalife.com www.wayalife.com
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Thank you for the write up link. I did buy a toe in/out measurement kit with matching tapes. I’m reasonably confident I have a bit of toe out as well as not enough caster. Seems like this might be a deal where a small piece of everything could add up to the answer.

In any case, I will look this link over in detail to make sure I’m not missing anything in my plans.

Thank you!
 
CJ007 said:
Well that leads me back to the beginning…. Why are my 37s okay at virtually any speed and my 39s only good to 35mph?
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39s are larger and heavier

CJ007 said:
Something is different. Something matters. Is it as simple as me being on the fringe with my 37s and then all of a sudden out of balance 39s exacerbate every weakness and death wobble?
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Yes. With the 37s, the steering is able to damp the resonance created by whatever part is worn, loose or flexing. Adding larger, heavier tires places enough extra demand that the resonance causing the DWs is now over whelming whatever has been damping it.

To fix the DWs, you need to find what is worn, loose or flexing. You need to find what has play that shouldn’t.

Primary cause of DWs is loose/worn ball joints; loose/worn/bent/flexing track bar; loose/worn/bent/ flexing drag link.

Other sources are worn unit bearings; loose/worn/bent control arms; loose/worn/bent pitman arm; loose steering box mount bolts, frame cracked at steering box mount;
CJ007 said:
…I’m missing something.
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Don’t fall into the trap thinking that because the DWs showed up after changing to the larger tires that the larger tires are the cause. That’s like saying inflating the tire is causing it to leak. No. The tire leaks because there’s a hole. Inflating the tire just made it obvious.

Don’t waste time or money on an alignment before finding and fixing the bad parts, or you’ll be doing an alignment twice.
 
GP NOIR said:
39s are larger and heavier


Yes. With the 37s, the steering is able to damp the resonance created by whatever part is worn, loose or flexing. Adding larger, heavier tires places enough extra demand that the resonance causing the DWs is now over whelming whatever has been damping it.

To fix the DWs, you need to find what is worn, loose or flexing. You need to find what has play that shouldn’t.

Primary cause of DWs is loose/worn ball joints; loose/worn/bent/flexing track bar; loose/worn/bent/ flexing drag link.

Other sources are worn unit bearings; loose/worn/bent control arms; loose/worn/bent pitman arm; loose steering box mount bolts, frame cracked at steering box mount;

Don’t fall into the trap thinking that because the DWs showed up after changing to the larger tires that the larger tires are the cause. That’s like saying inflating the tire is causing it to leak. No. The tire leaks because there’s a hole. Inflating the tire just made it obvious.

Don’t waste time or money on an alignment before finding and fixing the bad parts, or you’ll be doing an alignment twice.
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I'll add when checking the track bar, remove it and check the bracket holes on both ends to make sure they are not oval shaped; just went thru this, luckily it was tight enough to get me home from Moab but the play was still slight enough that by the time I got home the oval had gotten worse - one bump at 35mph and rodeo time.

I already had a Synergy sector shaft brace and a Clayton SS relocation bracket which took care of the oval shaped mounting hole issue - replaced both ends of the Synergy TB just for my own peace of mind.
 
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