Track bar bushing causing death wobble

KCsTJ

KCsTJ

TJ student
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Farmersville, TX, United States
Stock 05 Sport with a 2" lift. Track bar bushing is cracked and triggers death wobble on occasion.
A jeep buddy says to repair it by getting a new track bar.
Can I remove the track bar and press out the bad bushing?
Press in a new bushing?
 
A bad track bar bushing doesn't actually cause DW, it just lets it develop more easily. An imperfect front tire balance is usually the root cause of DW.
 
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KCsTJ said:
Stock 05 Sport with a 2" lift. Track bar bushing is cracked and triggers death wobble on occasion.
A jeep buddy says to repair it by getting a new track bar.
Can I remove the track bar and press out the bad bushing?
Press in a new bushing?
Click to expand...
It won't cause death wobble , but can allow death wobble , press in a Moog K-7252 from 3/4 ton Dodge with a 14mm bolt...I run them..they make a stock bushing look like a joke.

If you get wobble after a hard lick, that's usually the track bar,but can be another loose component of cumulative slightly loose ones.

I'm sure you maintain yours, so you will nail it. Hope the pool business is good.

" I think corralling people in a retail business down a path because of Covid 19 is like a no peeing section in a swimming pool."
 
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AndyG said:
It won't cause death wobble , but can allow death wobble , press in a Moog K-7252 from 3/4 ton Dodge with a 14mm bolt...I run them..they make a stock bushing look like a joke.

...
Click to expand...

How so? Is there more rubber?
 
N
jjvw said:
How so? Is there more rubber?
Click to expand...
No sir, less and denser , plus a larger bolt . If you look at one for an an F 250 , it's even less rubber than the Dodge and an even larger bolt .

Those bushings don't need much flex and need just enough rubber to keep our harshness. The Fords trucks seem to last longer, but go bad fast once they fail. The TJ's fail progressively , and do ok overall, but you don't need that much rubber to get the job done -and I think larger tires transmit more inertia on bumps to the system.

Holding the axle centered without excess side to side flex is key. If you put one in a TJ, you can immediately feel the improvement.
 
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AndyG said:
N
No sir, less and denser , plus a larger bolt . If you look at one for an an F 250 , it's even less rubber than the Dodge and an even larger bolt .

Those bushings don't need much flex and need just enough rubber to keep our harshness. The Fords trucks seem to last longer, but go bad fast once they fail.

Holding the axle centered without excess side to side flex is key. If you put one in a TJ, you can immediately feel the improvement.
Click to expand...

When I was deciding on Currie track bars, I specifically picked the one that uses the stock size bolt because it uses a rubber bushing and because it uses more rubber than the k7252.
 
jjvw said:
When I was deciding on Currie track bars, I specifically picked the one that uses the stock size bolt because it uses a rubber bushing and because it uses more rubber than the k7252.
Click to expand...
If it works it works, it's just not always more rubber that's the answer...less rubber and denser means less flex..that seems to feel great on the road. I'm sure there is a lot I don't know at play though.

I think the 10 mm bolt is marginal also, especially if ever overtorqued. It's all scaled for stock tires as far as factory.

I know John Currie does his homework. I love his stuff.
 
jjvw said:
There is a lot to unpack in there
Click to expand...
Absolutely, and there is a point where a system is too rigid..also bars that are heim joint at the frame transfer a lot more stress on the bushing end likely.

A Johnny joint is a good example...it's way more steel and less urethane . It gives control without flexing too much or being too stiff.

Also, it's give and take. If the stocker was harder rubber, it would last longer and drive better..but it tends to do fine with stock tires overall anyway. They all eventually lose strength.

I just love the combination of more bolt and harder rubber...it makes a TJ track so good and I think it's a good scale up for large wheels and tires.

If it's more rubber , it has to be strong rubber..and if it's less ....it has to be strong...maybe moreso.

I think the TJ bushing is designed more for axle roll/ flex overall than the big trucks.
 
All I'll say is that I wanted more rubber specifically because of my shock travel. Currie also happens to use a dual durometer rubber bushing on their smaller bolt track bar. I have a k7252 on the shelf just in case I wasn't able to successfully use the stock size bolt in the drilled axle side mount. So far, the smaller bolt in the drilled hole along with the thicker bushing has worked well over the last 8 months of daily driving and however hard my wheeling might be.

My point is that the movement at the axle is controlled either way. And I'm not entirely sure what problem the k7252 is solving beyond the hotdog in a hallway that a drilled mount might lead to.
 
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Jerry Bransford said:
A bad track bar bushing doesn't actually cause DW, it just lets it develop more easily. An imperfect front tire balance is usually the root cause of DW.
Click to expand...
Yes agree. I should have been.more specific. It doesn't happen on every bump I hit, it's opportunistic death wobble.
Me and a buddy checked things and the only thing we found was cracks in the track bar rubber so repairing that should solve this little death wobble.
 
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jjvw said:
All I'll say is that I wanted more rubber specifically because of my shock travel. Currie also happens to use a dual durometer rubber bushing on their smaller bolt track bar. I have a k7252 on the shelf just in case I wasn't able to successfully use the stock size bolt in the drilled axle side mount. So far, the smaller bolt in the drilled hole along with the thicker bushing has worked well over the last 8 months of daily driving and however hard my wheeling might be.

My point is that the movement at the axle is controlled either way. And I'm not entirely sure what problem the k7252 is solving beyond the hotdog in a hallway that a drilled mount might lead to.
Click to expand...
I don't think Moog competes with the good aftermarket products as much as it is an improvement over stock.
 
AndyG said:
It won't cause death wobble , but can allow death wobble , press in a Moog K-7252 from 3/4 ton Dodge with a 14mm bolt...I run them..they make a stock bushing look like a joke.

If you get wobble after a hard lick, that's usually the track bar,but can be another loose component of cumulative slightly loose ones.

I'm sure you maintain yours, so you will nail it. Hope the pool business is good.

" I think corralling people in a retail business down a path because of Covid 19 is like a no peeing section in a swimming pool."
Click to expand...
It was death wobble after a hard lick, u nailed it. Was on a road that turned bad quick.
 
jjvw said:
I'm still not sure why that would be.
Click to expand...
Well , anything's an improvement over a bad one. And I'm thinking stock track bar....with non stock larger tires. I think they transmit more energy ... If I roll a stock tire to you, vs. a 12x 15x 33, it's gonna be a lot harder to stop the 33, no matter how it's moving ..forward or side to side.

If you have more rubber and it's quality stuff and you get progressive control from it you're going to be happy... And if you have less rubber that is real dense and it holds the front end centered well, you are going to be really happy.

I tend to think the firmer set up works well with big tires, and love the way my TJs handle bumps with larger tires... At the same time I may tend to like a firmer steering feel.

Also, it is in the category of the kind of nuance many people wouldn't notice or care about .

Also... I tend to make uneducated conclusions... For instance thinking if a bushing of that design works so well on a big truck, it's got to be the bomb on a TJ. In no way do I have the knowledge to make that correlation.

The bottom line is a quality bushing, in any configuration, that's as dense as stock or denser, should perform well.
 
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AndyG said:
Well , anything's an improvement over a bad one. And I'm thinking stock track bar....with non stock larger tires. I think they transmit more energy ... If I roll a stock tire to you, vs. a 12x 15x 33, it's gonna be a lot harder to stop the 33, no matter how it's moving ..forward or side to side.

If you have more rubber and it's quality stuff and you get progressive control from it you're going to be happy... And if you have less rubber that is real dense and it holds the front end centered well, you are going to be really happy.

I tend to think the firmer set up works well with big tires, and love the way my TJs handle bumps with larger tires... At the same time I may tend to like a firmer steering feel.

Also, it is in the category of the kind of nuance many people wouldn't notice or care about .

Also... I tend to make uneducated conclusions... For instance thinking if a bushing of that design works so well on a big truck, it's got to be the bomb on a TJ. In no way do I have the knowledge to make that correlation.

The bottom line is a quality bushing, in any configuration, that's as dense as stock or denser, should perform well.
Click to expand...

This is very reminiscent of the debate over whether or not control arm ends effect the ride quality. The track bar is just a control arm.
 
jjvw said:
This is very reminiscent of the debate over whether or not control arm ends effect the ride quality. The track bar is just a control arm.
Click to expand...
Yes, and it's the connection that matters, not the arm. If it's good, it's good. The K-7252 is just a means to an end Dave Kispaugh devised.
 
AndyG said:
Yes, and it's the connection that matters, not the arm. If it's good, it's good. The K-7252 is just a means to an end Dave Kispaugh devised.
Click to expand...
If Dave is replacing the stock bushing of the stock track bar with the k7252, then I'm still confused about what problem is being solved. Even if the entire purpose is to use the larger bolt. But no harm is being done either.
 
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