A shock to my pocket book

[El Chapo]

4 hours ago, Doc Eagle said:

I tried running BFG KO3s in two of my older 2 door Jeep TJs.  They both gave me death wobble on the old Jeeps.  The explanation I got from two tire guys I trust was that running oversized (I was only running 33") BFK "truck tires" on the super light TJs was an issue because the BFG KOs were originally designed for much heavier vehicles and when you ran them at highway speeds for extended periods of time, which most of us running a Jeep as the DL do, they would go out of round and have sidewall internal issues.  

 

I had to remount and rebalance the same tires multiple times to fix this (tire life WAS exceptionally long with them) and finally got tired of it so I swore off BFGs for a while.  My understanding is that the problem has been addresses by both Jeep and BFG and now there's no problem.  Otherwise they were great tires!!!..... Unless you hit a deep puddle on the highway at high speed in the aforementioned light Jeeps 🤣

 

Death wobble is caused by alignment on a solid axle vehicle (assuming your balljoints and steering components are tight).

 

Toe your wheels in 1/8-1/4" and it'll be gone.  I align my vehicles with a tape measure and I don't think I could do better with a fancy machine.

 

Worst case scenario, even a cheap steering stabilizer will do the rest.

 

Tires have nothing to do with death wobble other than that they need to be pointed in the correct direction to get rid of it.

 

The only exception to this is kingpin axles--they can be a real pain to get them tight enough to eliminate it entirely (but there are solutions for that, too).

 

I personally avoid buying BFGs because I have had them before and I like the opportunity to try something new, but my wife's F150 has a set and I was surprised how good they were in mud the last time we took it out in the desert and there were surprise mudholes.  I would have seriously considered the KO3s if they were out in her size though, they look like some nice improvements to a proven and well-regarded tire.

 

I was actually going to get her the Falken RT tire or at least consider it until I read online that they're garbage in snow and ice, and while we don't get a lot of that, I was willing to compromise some off road performance to have a vehicle that we can drive in the mountains without worrying about that.  If we had mud here regularly, I may have gone the other way since they have so much more void ratio.

 

I went with C rated tires to avoid the heavier tires that come with putting E rated tires on a Jeep though, and that was a major consideration for me when shopping for her.  It's a shame that almost all of the tires out there are D and E load rating now, and you have to pick carefully to get Cs.  I'm hoping the softer/lighter tires will hook up better off road.  

[Eyesa Horg]

I gotta tell ya "Death wobble" was real on brandy new Jeeps when I worked in the service dept. Had to test drive with a lady and went over an RR crossing. We were going about 35 and holy crap did that thing get crazy for a bit! Techs messed with alignment tires and fancy off road stabilizers til she stopped coming back! There were least 1 a month that came in.

[Doc Eagle]

1 hour ago, El Chapo said:

 

Death wobble is caused by alignment on a solid axle vehicle (assuming your balljoints and steering components are tight).

 

Toe your wheels in 1/8-1/4" and it'll be gone.  I align my vehicles with a tape measure and I don't think I could do better with a fancy machine.

 

Worst case scenario, even a cheap steering stabilizer will do the rest.

 

Tires have nothing to do with death wobble other than that they need to be pointed in the correct direction to get rid of it.

 

The only exception to this is kingpin axles--they can be a real pain to get them tight enough to eliminate it entirely (but there are solutions for that, too).

 

I personally avoid buying BFGs because I have had them before and I like the opportunity to try something new, but my wife's F150 has a set and I was surprised how good they were in mud the last time we took it out in the desert and there were surprise mudholes.  I would have seriously considered the KO3s if they were out in her size though, they look like some nice improvements to a proven and well-regarded tire.

 

I was actually going to get her the Falken RT tire or at least consider it until I read online that they're garbage in snow and ice, and while we don't get a lot of that, I was willing to compromise some off road performance to have a vehicle that we can drive in the mountains without worrying about that.  If we had mud here regularly, I may have gone the other way since they have so much more void ratio.

 

I went with C rated tires to avoid the heavier tires that come with putting E rated tires on a Jeep though, and that was a major consideration for me when shopping for her.  It's a shame that almost all of the tires out there are D and E load rating now, and you have to pick carefully to get Cs.  I'm hoping the softer/lighter tires will hook up better off road.  

Again, I'm not a mechanic and I was just passing along what the tire guys said and all I know is that after remounting and re-balancing the issues went away.  But that is ANCIENT history and not very important anymore.  The information and story are now almost 20 years old and I'm REALLY happy with my current tires, they have performed admirably for lots of rugged off-road miles and a few thousand high speed highway miles.  Just drove from Las Vegas, though Utah, through Colorado into Wyoming and back through Wyoming and Utah.  With some NICE off-roading in Wyoming involving DEEP snow, deep mud holes and steep inclines.  The Falkens performed better than I ever expected.

[The Original Lumpy Gritz]

44 minutes ago, Eyesa Horg said:

I gotta tell ya "Death wobble" was real on brandy new Jeeps when I worked in the service dept. Had to test drive with a lady and went over an RR crossing. We were going about 35 and holy crap did that thing get crazy for a bit! Techs messed with alignment tires and fancy off road stabilizers til she stopped coming back! There were least 1 a month that came in.

Over inflation of the tires is a common cause when going to way oversized tires.

[Eyesa Horg]

These were stock vehicles sold by the dealer. But like Doc, it was 15 years ago that I worked there!

[The Original Lumpy Gritz]

2 hours ago, El Chapo said:

 

Death wobble is caused by alignment on a solid axle vehicle (assuming your balljoints and steering components are tight).

 

Toe your wheels in 1/8-1/4" and it'll be gone.  I align my vehicles with a tape measure and I don't think I could do better with a fancy machine.

 

Worst case scenario, even a cheap steering stabilizer will do the rest.

 

Tires have nothing to do with death wobble other than that they need to be pointed in the correct direction to get rid of it.

 

The only exception to this is kingpin axles--they can be a real pain to get them tight enough to eliminate it entirely (but there are solutions for that, too).

 

I personally avoid buying BFGs because I have had them before and I like the opportunity to try something new, but my wife's F150 has a set and I was surprised how good they were in mud the last time we took it out in the desert and there were surprise mudholes.  I would have seriously considered the KO3s if they were out in her size though, they look like some nice improvements to a proven and well-regarded tire.

 

I was actually going to get her the Falken RT tire or at least consider it until I read online that they're garbage in snow and ice, and while we don't get a lot of that, I was willing to compromise some off road performance to have a vehicle that we can drive in the mountains without worrying about that.  If we had mud here regularly, I may have gone the other way since they have so much more void ratio.

 

I went with C rated tires to avoid the heavier tires that come with putting E rated tires on a Jeep though, and that was a major consideration for me when shopping for her.  It's a shame that almost all of the tires out there are D and E load rating now, and you have to pick carefully to get Cs.  I'm hoping the softer/lighter tires will hook up better off road.  

Castor is a big issue too.

You want 6-7* positive castor and 1/8-3/32" total toe-in. 

Make sure the camber is the same on both sides.

[watab kid]

10 hours ago, Forty Rod SASS 3935 said:

That's what I thought about 45,000 miles ago.

im at 159+ on my 'new to me truck' thats a year plus old , im not one to buy new , i like one thats been cared for and given a reasonable breakin , ill get well over 200k on this one , it came with new tires ill see how long they last , 

the last three trucks i drove were brand new - the company bought them in my name , all three wen over 250k and the last one was 20 years old when i traded it on my current truck , the one before those three company trucks was used but very modestly - i put [combined with my wife and daughter] went over 350k , good maintenance is rewarded 

[Sedalia Dave]

Just an FYI if a tire is truly out of round no amount of remounting and rebalancing will fix it. It may mask the problem for a little while but that's all.

 

Out of round tires are almost always the result of a manufacturing defect. 

[Doc Eagle]

20 minutes ago, Sedalia Dave said:

Just an FYI if a tire is truly out of round no amount of remounting and rebalancing will fix it. It may mask the problem for a little while but that's all.

 

Out of round tires are almost always the result of a manufacturing defect. 

I have no clue so I'll take your word for it.  But that was basically what was happening to me.  Everything would be Ok for a while and the one day, wham and back to the tire guy.  What made his explanation credible was that it happened to me with two identical Jeep configurations 5 model years apart and the exact same tires bought new for both of them.  I figured one instance is bad luck but two instances is a trend that I didn't want to play with anymore.  BUT again, 20 year old information.

[El Chapo]

On 8/13/2025 at 5:59 PM, The Original Lumpy Gritz said:

Castor is a big issue too.

You want 6-7* positive castor and 1/8-3/32" total toe-in. 

Make sure the camber is the same on both sides.

 

Caster will cause handling issues but it won't cause death wobble.  You definitely want all the caster you can get no matter what the book says.  Even 10 degrees is not too much if you have big tires, although you'll probably put a hurtin' on the driveshaft to get that without cutting the axle.

[The Original Lumpy Gritz]

31 minutes ago, El Chapo said:

 

Caster will cause handling issues but it won't cause death wobble.  You definitely want all the caster you can get no matter what the book says.  Even 10 degrees is not too much if you have big tires, although you'll probably put a hurtin' on the driveshaft to get that without cutting the axle.

Not enough castor WILL cause a wobble.  

You don't want more than 7* positive. 

I say this with over 40+ years of do'n front-end work. 

[El Chapo]

On 8/15/2025 at 12:55 PM, The Original Lumpy Gritz said:

Not enough castor WILL cause a wobble.  

You don't want more than 7* positive. 

I say this with over 40+ years of do'n front-end work. 

 

With big tires, I'd love to have more than 7 degrees if the driveshaft wouldn't be at an extreme angle.  I'm setting up my wife's front suspension this afternoon after work and I'd love to have 10 degrees of caster if I could get away with it, but I'm probably going to have to settle for 6. I'm not sure where you got the idea that no more than 7 is permissible after 40 years of front end work--the spec for her jeep goes up to 8.5 degrees from the factory (but I probably can't run it that high with the lift she's running and keep a driveshaft in it).  I'm sure those military vehicles out there with really big tires run even more than that.  More caster increases steering effort but other than that, makes the entire front end more stable.

[The Original Lumpy Gritz]

6 hours ago, El Chapo said:

 

With big tires, I'd love to have more than 7 degrees if the driveshaft wouldn't be at an extreme angle.  I'm setting up my wife's front suspension this afternoon after work and I'd love to have 10 degrees of caster if I could get away with it, but I'm probably going to have to settle for 6. I'm not sure where you got the idea that no more than 7 is permissible after 40 years of front end work--the spec for her jeep goes up to 8.5 degrees from the factory (but I probably can't run it that high with the lift she's running and keep a driveshaft in it).  I'm sure those military vehicles out there with really big tires run even more than that.  More caster increases steering effort but other than that, makes the entire front end more stable.

What, model/year Jeep does she have?

You hit a rut or a rock while off road with anything much over 7* positive castor. 

You'll see and feel why it's not a good Idea, especially in a CJ with solid front axles.

BTDT 

[El Chapo]

18 hours ago, The Original Lumpy Gritz said:

What, model/year Jeep does she have?

You hit a rut or a rock while off road with anything much over 7* positive castor. 

You'll see and feel why it's not a good Idea, especially in a CJ with solid front axles.

BTDT 

 

Hers is a 2000 XJ.

 

She's definitely going to need a lot of caster with big tires on a toy front axle.

[The Original Lumpy Gritz]

2 hours ago, El Chapo said:

 

Hers is a 2000 XJ.

 

She's definitely going to need a lot of caster with big tires on a toy front axle.

How much castor does if have now?

What about camber? 

I run 33's with 7* positive castor and the steering is fine with no wobble at all even on the freeway at 70 mph.

[Finagler 6853 Life]

On 8/12/2025 at 5:24 PM, WD Farren said:

 

 

That worn tire you wanted to replace just blew out.  Your mother in law in the car says, “Some great mechanic you are…”

 

Granny would be riding on top of the car iffn she said that to me. Or maybe the trunk.  It's a long walk home grandma.

[Finagler 6853 Life]

In days of yore, I had an old road warrior salesman tell me, good tires are cheap insurance.

[El Chapo]

2 hours ago, The Original Lumpy Gritz said:

How much castor does if have now?

What about camber? 

I run 33's with 7* positive castor and the steering is fine with no wobble at all even on the freeway at 70 mph.

 

Camber on a straight axle is generally not adjustable.  For older vehicles with conventional wheel bearings there are shims for behind the spindles, which I have never used on anything, but for unit bearings, usually there isn't anything.

[The Original Lumpy Gritz]

1 hour ago, El Chapo said:

 

Camber on a straight axle is generally not adjustable.  For older vehicles with conventional wheel bearings there are shims for behind the spindles, which I have never used on anything, but for unit bearings, usually there isn't anything.

You can buy off-set top ball joints to correct camber.

What I used in my Dana 30 front axle on my CJ-7. 

[Doc Eagle]

4 hours ago, Finagler 6853 Life said:

In days of yore, I had an old road warrior salesman tell me, good tires are cheap insurance.

And he was correct.  I made the mistake of buying "cheap tires" for one of my cars ONCE.  First jug handle I took on the new tires I almost went off the road, the darn things had the sidewall flex of a marshmallow...